he JOWETT Slogan — ‘The little engine with the big pull’ — is so apt and characteristic of the car that it has become known and quoted throughout the British Empire.
We also append a number of other slogans and complimentary descriptions which have been applied to our cars from time to time.
The car which was built to last a lifetime — and does.
Jowetts never wear out — They’re left to next of kin.
If you want to go where a JOWETT won’t, you’ll need a crane.
You cannot motor for less than on a JOWETT, unless you are always a guest.
A JOWETT has:
the pull of an elephant;
the appetite of a canary;
the docility of a lamb.
Where there is a way, the JOWETT will go — easily!
The JOWETT made luxury motoring economical.
The seven that passes a seventeen like a seventy.
Makes milestones s’milestones.
Try not the pass, the old man said, until he saw the car was a JOWETT; then he asked for a lift — and got it!
Carries the whole family at rail fare for one.
THE FOLLOWING DATA, IF ENTERED ON PURCHASING CAR, WILL PROVE OF GREAT SERVICE TO YOU AT MOST UNEXPECTED TIMES.
Type: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Car No. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supplied By: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Main . . . . . . . Compensating . . . . . . . Choke . . . . . . .
Valve Rocker Levers: 1 . . . . . 2 . . . . . 3 . . . . . 4 . . . . . .
Tyres No . . . . . . Replaced at . . . . . . . . . . . . . . . Miles
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Insurance Policy Number: . . . . . . . . . . . . . . . . . . . . . .
Company: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Premium: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Expires: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Renewed: . . . . . . . . . . . . . Renewed: . . . . . . . . . . . .
Registration Licence Expires: . . . . . . . . . . . . . . . . . . . . Renewed: . . . . . . . . . . . . Renewed: . . . . . . . . . . . . .
Driving Licence Number: . . . . . . . . . . . . . . . . . . . . . . .
Expires Each Year: . . . . . . . . . . . . . . . . . . . . . . . . . .
Notes: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Further copies of this Instruction Book can be had on application.
Price 1/6 each
JOWETT SLOGANS 1
CAR DATA 1
CHAPTER 1. Method of Ordering Spares and Replacements 2
CHAPTER 2. Driving Hints 2
CHAPTER 3. Road and Car Camaraderie 5
CHAPTER 4. Oiling and Adjustments 5
CHAPTER 5. Overhauling 8
CHAPTER 6. General Care of Coachwork, Etc. 10
CHAPTER 7. Care of Tyres and Tubes 10
CHAPTER 8. Electrical System 12
he basic idea of the designers and producers of the JOWETT Light Car, from its inception in 1906 to the present time, has been to offer the simplest and most reliable vehicle possible to manufacture, commensurate with the work it had to perform. Simplicity and lightness have unquestionably been obtained, but without sacrificing sturdiness and unfailing reliability.
The JOWETT Light Car has earned a reputation for reliability which cannot be refuted, and the elimination of all unnecessary gadgets and so-called refinements has resulted in a car capable of withstanding hard service year in and year out without constant tuning and expensive annual overhaul.
Its light weight and high power-to-weight ratio makes it possible to maintain an average road speed over a day’s run, quite 30 per cent, in excess of that anticipated from an engine of 907 c.c. capacity, and with its very moderate bottom gear ratio of 15.1 to 1, it is capable of climbing the severest gradients easily. This assures to the owner a clean and easy ascent, with full load, of any main road hill, although he may come upon it unawares, with his engine possibly not in the best of tune.
Such a car then deserves the small amount of regular attention necessary, and it is in the owner’s interest to thoroughly master the instructions contained in this booklet.
We are at all times happy to assist Jowett owners with our advice on any matter concerning the car, and shall be pleased to reply to queries by return post whenever possible. Write on one side of paper only; be as brief as possible, and always quote the car number. Don’t mix queries and requests for spares as they are dealt with by different departments. Address all communications to the Company and not to individuals.
It has been our intention in compiling this booklet to deal with the various points conversationally, and we hope, since technicalities have been almost entirely omitted, you will read it through and thus become intimately conversant with the details of the car.
THE METHOD OF ORDERING SPARES AND REPLACEMENTS
(Read this carefully)
e hold in stock, ready for immediate delivery, a complete range of parts of our vehicles that are liable to wear or damage by accident, and always despatch replacements same day as requested, if properly ordered and the necessary information given.
In ordering replacements, delay in receipt of same and trouble at these works will be avoided if care is taken in following the appended instructions:
1. ALWAYS QUOTE THE CAR NUMBER which is stamped on the metal plate on the instrument board.
2. ALWAYS QUOTE THE PART OR ASSEMBLY NUMBER.
3. ALWAYS CONFIRM telegram or telephone Orders by letter immediately.
4. IF YOU CANNOT LOCATE PART NUMBER, adequately describe it in your Order, and where possible send damaged part if not too bulky.
5. IN ALL CASES cash must be sent with Order, unless you have a credit on our books.
6. POSTAGE IS EXTRA, and sufficient Cash to cover must be enclosed with Order.
7. PACKING CASES ARE CHARGED, but credited on return. This applies to bulky items only.
We frequently receive car parts unlabelled, and much delay is occasioned in consequence. When returning parts for repair, examination, or any other reason, be sure to pack them or label them in such a way that the ownership is easily discernable. We need your name, address and car number always. Help us to help you by observing this rule; also, every letter you write, on whatever subject should be headed – re car number so-and-so.
For the convenience of clients, we are prepared to accept deposits of up to £5, which will be entered to customer’s credit.
This enables us to despatch parts often in a few minutes after receipt of instructions or damaged part, thus avoiding delay. Carriage or post will be charged at cost.
Otherwise pro-forma invoice will be sent, unless cash is received with order. This should particularly be noticed by overseas users of our cars.
We have received many compliments on the facility obtained by clients who use this system.
REPLACEMENT UNDER OUR GUARANTEE
(Read terms of guarantee on back page of this book)
All replacements claimed under our guarantee will be charged for in the usual way, but credit will be immediately allowed if, on investigation, the part is agreed to be faulty.
The part must be returned to these works, fully paid, accompanied by an intimation that you desire it to be repaired or replaced under the terms of our guarantee.
Failing compliance with this, parts will lie here at owner’s risk and our guarantee or any implied guarantee shall not be enforceable.
If you compare the cost of spares and replacements for a JOWETT car with those of any other make you will at once appreciate that there is only a small margin of profit. Again, you would hardly expect a trader who had never seen you to send you goods without an opportunity of ascertaining the position of your credit.
MORAL: Send us a credit (we will not accept more than £5), and you can rely on the despatch of spares by return.
NOTE – whether you write us, ’phone us or telegraph us, always give us your Car Number. Thank you.
he driving and general control of a motor car can almost be said to consist of a series of standardised functions, each applicable to a large majority of the different makes. But every car has its own little peculiarities, which, if mastered, tend to the more efficient and economical running of the individual car or type.
The following hints are, for the most part, only what the experienced motorist would instinctively look for and carry out, but several of them apply more particularly to the JOWETT LIGHT CAR, and for this reason it is hoped that every owner will peruse them.
To the beginner the descriptions will, in some cases, make the operation appear complicated, but quite the reverse is the case in actual practice, and he is advised to sit in the car (with the engine stationary) and carry out the movements a number of times, thus becoming familiar with them before trying his prentice hand with the car under way.
The writer of these notes has dispelled all fear from the minds of beginners somewhat as follows:
Motor-car driving cannot require anything but the exercise of ordinary common sense, because it would be unreasonable to suppose that the many thousands of people who have bought and driven cars during the past ten years possessed, on the average, anything more than their share of that very necessary and useful commodity – “common sense”.
There are, of course, degrees of skill in driving, as in any other function actuated by a mass of people, but the writer submits that the two essentials are common sense and caution.
1. STARTING THE ENGINE
See that you are right for petrol in the tank, oil in the engine and water in the radiator.
Pull the side brake (hand lever) right on.
Place the gear lever in central (neutral) position.
Fully retard the ignition, whether hand or electric starting.
Flood the carburettor slightly.
Turn the engine two or three times, with air strangler closed, to suck mixture into cylinders. Switch on the ignition and pull engine sharply over compression, or, if fitted with a starter, depress the starter switch.
2. Engine Running
Having started the engine, sit in the driving seat and press the accelerator pedal, situated between the clutch and foot brake pedals. This will cause the engine to increase its speed. Do not allow engine to “race” in free position.
3. OPERATING THE GEARS
A – Reverse Catch, B – First and Reverse Selector
C – Second and Top Selector, D – Spring Plunger
E – Oil Hole
To operate the gears:
Switch off engine
Sit in driving seat
Keep side brake “on”
Press left hand pedal (clutch) thus taking clutch out of engagement with engine
Grasp the gear lever in right hand and pull backward and slightly inward, into first gear position, keeping clutch pedal down with left foot. You have now connected first gear with back axle, but not with engine. Imagine engine turning over under power. If you now let the clutch “in” by gradually raising left foot, with the side brake “off”, the car would glide gently forward if the accelerator pedal were further depressed to give more engine power.
Practice this without the engine until quite familiar with the operation, before attempting on the road. Do not go out without an experienced driver until you are confident.
Examine the drawings in the next column and you will realise that, when under way, there are a number of gear wheels all turning at different speeds.
The necessity of “declutching” when changing gear is in order to remove the drive from the gears by disconnecting them from the engine until it is accelerated to correspond with the new ratio if changing into a lower gear, or decelerated if changing into a higher gear. If you attempt to change gear without declutching you will almost inevitably damage the gearbox.
Having practised the engagement of first gear, now let us try second speed, as follows:
Declutch, push gear lever forward and to right across the gate into second speed position.
Let in the clutch again.
With the engine stationary it may not always be possible to go from one gear to another, due to the pinions in the gearbox not revolving as they will be when the car is under way on the road. If this happens, push the car forwards a few inches, when the lever will slide into the required position.
To obtain third or top gear, declutch, pull the gear lever right back (not crossing the gate) and let in clutch.
The remaining gear i.e., reverse, will be found forward of the first speed position. A safety catch which drops into reverse position, is provided to prevent the driver inadvertently touching the reverse when going across the gate from first to second speeds.
The reverse gear is obtained in exactly the same manner as the others, that is, declutch, push lever to left and forward, then engage clutch. N.B. – Never engage reverse without first bringing the car to an absolute standstill.
These Drawings show what happens when the change speed lever is shifted into the respective gear position.
4. Having familiarised ourselves with the gearchange mechanism, let us now consider the braking problem. It is more important that you shall be able to pull up the car quickly tanto make it travel quickly.
SAFETY FIRST EVERY TIME
Sitting in the driving seat, you find on your right hand a lever (plated), which operates the back wheel brakes, one on each wheel.
The brake is “on” when the lever is pulled back or towards you. A ratchet and pawl is provided to hold brake “on” at any desired tension and is released by thumb pressure on the button passing down the handle. Always grip the lever with the thumb on the button, keeping same depressed unless brake is required to stay at the “on” position.
It will be evident that if brake lever is pulled backwards as above, the car will be brought to a standstill and if left “on” will hold the car on a hill. The second brake is operated by the foot by pressure on the right-hand foot pedal. This brake is not provided with a ratchet and must be held on where necessary,
Imagine car travelling on top gear at 20 m.p.h. Required to bring car to a stop.
First take foot off accelerator pedal, declutch, and if no traffic in the way, allow the car to run gently to a standstill, then hold gently with the side brake.
This method of speed variation or stopping is much the most economical and tends to long life of brakes, car parts and tyres, and should be utilised wherever possible.
If traffic conditions necessitate a quick pull up, take right foot off accelerator pedal and press right-foot pedal with a gentle, steadily increasing pressure. Declutch a fraction of a second after brake is applied. Hold car on side brake as required.
Either foot or hand brake can, of course, be used, as desired, or, in case of emergency, both can be applied simultaneously. As soon as possible push gear lever into neutral position and let clutch in again.
5. Let us now consider that we are going for a run, and record all operations as previously described, but abbreviating where possible. It is presumed throughout that steering will not present any difficulty, since turning wheel to left or right steers car accordingly.
Pull “on” side brake, put gear lever neutral, turn on petrol, flood carburettor, retard ignition, turn engine to suck in petrol mixture, switch ignition “on,” turn engine sharply or press starter button. If everything is in reasonable order engine should start at once.
With engine ticking over free, declutch, engage first gear, release brake, accelerate engine, let clutch in gently, and away we go.
We shall keep in low gear some little time until we get accustomed to the “feel” of the car, steering, etc. Now we pull up, to test our skill in use of brakes.
Decelerate (which means take foot off accelerator pedal), then apply brake gently, immediately afterwards pushing clutch pedal down or declutching. Put gear lever in neutral position as soon as car comes to rest.
Now, we’ll try again.
Declutch, engage first gear, accelerate, release side brake, engage clutch gently. We cannot go far on low gear, as our engine is racing away, so let’s go into second; declutch, decelerate, go steadily across the gate into second speed position, engage clutch, accelerate, and away we go!
There, that’s better! But we must now watch our steering, as we are travelling nearly 20 m.p.h. and our engine feels to want to go even faster.
Since we are travelling at a fair pace, we’ll test our brakes again; decelerate, apply brake and declutch. That’s good!
Now first gear again, declutch, select gear, accelerate brake off, clutch in. Now, second gear, decelerate, clutch out, select gear across gate and forward, clutch in and accelerate to make car pick up. Off We go, let her get to about 18 m.p.h. and we’ll try top gear. Ready? Declutch, decelerate, pull lever smartly back into top gear, clutch in and accelerate. A little wait after leaving second and engaging third speed would have been better, but we shall get that later when we have practised.
Doesn’t she run much sweeter on top? But be careful of that accelerator, or we shall be going too fast. A very little movement makes a big difference now.
Good gracious, look! Here’s a hill, quite steep, too; we shall have to change down into second gear since we are beginners.
Do as I tell you smartly and we shall sail out at the summit.
Here we are! Ready?
Keep foot hard on accelerate pedal, declutch, push gear lever smartly forward into second, engage clutch. Good, over the top we go, and now we’ll pull up for a smoke.
What about this double clutching? you say. Well, I didn’t want to confuse at first, but double clutching is really the best and most infallible way of changing down from top to second or second to first, but it requires a “knack” or facility obtained by experience. I shall have to tell you how it’s done, because if you watch me ‘do it my movements will be too quick for you to follow.
We’re in top gear and come to a stiff rise which calls for second gear.
Remember this: always keep your accelerator hard down when changing down, and hard up when changing up.
That’s easy to remember, isn’t it?
This is how it’s done. Accelerator hard down, clutch out, gear in neutral, clutch in, and out again quickly, gear in second, clutch in finally.
Sounds very complicated, doesn’t it? Well! you try it in a week or two and you’ll do it all right, but meanwhile you can go from top to second and from second to first exactly as I told you before, without double clutching. That will come later.
One word now. If you “miss” getting a gear, don’t grind away trying to get in. Pull the car up and start again. It saves “burring” over the entering wedges of the gears and makes you “watch your change” in more ways than one.
We must be getting back now, and I want you to reverse the car, as we cannot get round otherwise in this narrow road.
Start the engine. I leave it to you. Good! Now follow me carefully for the reverse action.
Lift that safety catch up so that you can get the gear lever into reverse position; declutch, push lever to the left and forward, brake off. Now we want to go backward to the right, so turn steering as though you were going forward and to right, accelerate a little, clutch in gently and round we go until the back wheels drop gently against the bank of the road or kerb. Brake on, clutch out, gear neutral. You must never attempt to go from reverse to first or first to reverse unless the car is absolutely stationary. Now get away on first with full left-hand lock and away we go on our homeward journey.
Up into second gear, then top, and down the hill.
Take your foot off accelerator pedal and leave clutch in.
We are now using the engine as a brake, and will only apply brakes as necessary to keep the car at a safe speed. The slowest speed is safest on a hill, particularly if there are bends in the road.
Pull side brake on a little, then if the hill were very long we should change over on to the foot brake for a time and thus avoid overheating either brake, because friction, you know, means heat.
If it were a very steep hill it might be advisable to stop the car or go very gently and drop into second or even first gear and so make the engine a much more powerful brake.
I want you to remember that the few seconds we lose by “taking care” do not add up to more than a few moments in a day’s run and are well worth while.
Now we are in sight of the garage, almost in no time, and .1 want you to come to a dead stop just outside and go in steadily on bottom gear. Garages are usually congested.
That was quite creditable! Switch engine off, turn petrol off, and when you come in at night make sure you leave everything in the off position, except the hand brake, which should be left in the “on” position.
ROAD AND CAR CAMARADERIE
You are now an initiate to the freedom of the open road. I do not presume to lecture you, but as you have entered into a glorious heritage, perhaps you will allow an “old hand” to offer a few suggestions as to how best to use that freedom for your own greater pleasure and safety, as well as that of other users of the King’s Highway, who may not be so conscientious as you are.
That, however, should not affect you, because you will use the road as you know is right, and ignore anyone who does not understand the ethics of these things.
Years ago, there was a wonderful camaraderie of the road, and almost every motorist exercised those little functions of politeness, willing assistance, and (sometimes) self-denial in order to assist in the general well-being of all parties. For instance, even to-day an old motorist descending a hill will give as wide a berth as possible to a motorist climbing. It’s no end of a help to him, because his car may be just at the “last gasp,” and, if baulked, it might mean a restart under awkward conditions.
Again, a knight of the road will never toot-toot violently for permission to roar past another on a hill, unless he is quite sure that his less fortunate fellow will not be inconvenienced and perhaps flustered at a time when he is coaxing his rather indifferent engine up the big hill.
I might add to these examples many others and propose to give one or two more, but I would like to say at this stage, that, having bought a JOWETT car, you will particularly apply the examples just quoted, because you own a car which can climb severe hills with such consummate ease that you will be more than pleased to give the other man all the room he desires — and more.
This camaraderie of the road is practised by the large majority of JOWETT owners. For instance, you will note that another JOWETT owner will almost always salute you as he passes.
He will never pass you standing on the roadside without assuring himself you are not in need of help. As a matter of fact, a very old friend of the writer was recently in trouble with his big limousine. He assures me that not a single JOWETT car passed him without the owner offering assistance, and one even offered to tow him to the nearest town—with his little JOWETT! Only Jowett owners applied the principles of road camaraderie. Will you carry on this good work? Your Jowett will engender the enthusiasm, the desire, because it will make itself a real “pal” to you, and, doing so, will make you one of this great band of “knights of the road.”
This is not sloppy sentimentality — it’s cold fact!
This enthusiasm has been the means of forming no less than three JOWETT Car Social Clubs, and a host of unofficial little clubs, or bands of JOWETT Car owners in various parts of the country.
And now for one or two more examples of applied camaraderie.
Never pass the man in front just because you know you can. One of the most exasperating things is to be passed by a man, and to find that as soon as he is ahead, he perceptibly slows down. Many times on a long run, when averaging a certain previously decided speed, a man has passed me and slowed down just as I have said. Desiring to maintain my average, I have had to re-pass him, whereupon down goes his throttle, and he is by me at a speed I do not desire to maintain, but slows up again and holds me, thus interfering with me in a most undesirable way. Of course, he doesn’t realise what he is doing, but you, as a JOWETT owner, will not pass the man in front unless you desire to keep ahead and out of his way, will you?
Nor will you travel mile after mile just a few yards behind another car, unless you signal him definitely that you do not desire to pass. Otherwise, he will be continually “on edge”, wondering if you are wanting to pass, or if he is holding you back.
Another little point which may not suggest itself to you at first. If you are driving behind another car at night, put your lights on “dim”. This avoids shining your headlights into the screen of the man in front — a very disconcerting thing as you will find out when the other fellow does it to you. In any case, you do not need bright lights when travelling behind another car.
I shall not attempt to instruct you in the ordinary rules of the road, as if you do not already understand them, you can obtain the information elsewhere.
Such suggestions as I have given are all concerned with the regaining — rebuilding if you will — of that fine road sense so general in the early days of motoring, and to my certain knowledge and belief, exercised more generally by JOWETT owners to-day than the owners of any other make of car. You will do good to the movement as a whole if you ask your friends to practise these things also.
Finally, if you have not hitherto been a “roadman”, you have quite a lot to learn. The rules of the road should be studied by every new motorist before he drives extensively, as it is usually during his novitiate that he is most apt to contravene these.
At the risk of being dubbed a “preacher”, I would enjoin you to pay some attention to these matters, and you will thereby derive infinitely more pleasure from the use of your car.
OILING AND ADJUSTMENTS
IT is to be noted that the engine, gearbox, and back axle are exactly the same in all models, and the following remarks will therefore apply equally to all models.
(Study large Oiling diagram carefully – Page 6)
The remarks contained in this chapter are intended as a general guide to the maintenance in proper running condition of the JOWETT LIGHT CAR. They are not intended to cover the operations necessary for a general overhaul, as this should be carried out by a garage or the car returned to our Service Department at Idle, where repairs of every description can be carried out under the best conditions by men who thoroughly understand our cars.
We strongly recommend the purchase of oil in drums, as by this means the cost is almost halved. There are a number of brands of oil suitable for our cars, but we use only Wakefield’s XL, and you will be well advised to order a drum for use after you have finished the can supplied gratis with the car.
On receipt of your instructions we shall be pleased to have a five-gallon drum delivered direct to your address. Then always carry a reserve supply with you, and thus avoid odd purchases. A quart container is supplied for this purpose.
LUBRICATION AND MINOR ADJUSTMENTS
The efficient lubrication of the car’s components is probably the most important item in its maintenance. One can safely say that if a film of oil is preserved on a working part wear will be almost infinitesimal over very long periods.
The oiling diagram supplied with the car should be studied carefully, and then pinned on the garage wall It indicates the various points on the chassis requiring lubrication The careful motorist will realise the difficulty of accurately placing either a mileage or time limit on the lubrication periods, as so much depends on the driver weather type of roads, etc It is obviously very much better to be guided by one s own judgment and to err on the safe side, if any.
With the exception of the main engine sump, gearbox, and back axle, the whole of the car can be lubricated in a few minutes, surely not too much to ask after many a strenuous mile.
The chassis is fitted throughout with Stauffer bolts of our own manufacture, for use in conjunction with a patent grease gun supplied with the car.
With this system the chassis can be thoroughly lubricated in a very few minutes. Greasing is no longer a messy operation, and should be done regularly.
When greasing front axle it is advisable to place jack under centre of axle. (side brake “on“) to take the load off the stub axles. Work the wheels about to spread the grease on the faces See Garage Oiling diagram for location of greaser bolts, etc.
The ball and socket joints, on the ends of the steering coupling rod are packed with grease at the works and should not need any further attention for about three months, when they should be repacked.
Do not overlook Stauffer at bottom of steering column for ring gear also oil the bushes at top of steady tube and steering column guide on dash board.
If you liberally grease all spring hangers and shackle bolts you will reduce wear and rattle to an absolute minimum. The gate change mechanism requires lubricating about every thousand miles, or as found necessary.
We recommend equal quantities of grease and oil melted together and allowed to cool, for use in the grease gun.
Use Castrol XL, which has been tested and found most suitable for our cars.
The following description of the pressure feed oiling system on the JOWETT should be read in conjunction with the drawing, which is not to scale, but diagrammatic:—
Diagram illustrating the pressure feed oiling system.
Oil is drawn from the oil sump, through the gauze oil filter (F) by the mechanical pump (P), and delivered into the pressure line. At the end of this line is a relief valve (V) acting as follows : – The oil pumped along the line is allowed to escape through a small bore hole, beyond which is a small piston or plunger in a barrel. The oil pushes the plunger along the barrel and thus operates the button (B) on the dashboard, thus indicating to the driver that the oil circulation is working. At the same time, the plunger, as it moves along the barrel, uncovers a hole leading by a pipe to the timing case, thus thoroughly lubricating the timing gears, whence it is returned to the sump.
What actually happens, then, is as follows: The amount of oil pumped along the pressure line at low speeds is just a little more than can easily be passed by the hole in the body of the relief valve, therefore, a small pressure is built tip in the pressure line, which forces oil through the oil ways (FB) and (RB), feeding oil to the front and rear main bearings, and via the drilled crankshaft to the big end bearings. From these big end bearings the oil is splashed to the cylinder walls and pistons.
It will be understood from the foregoing that as the engine speed rises the pump will supply more and more oil to the pressure line, and this tries to escape through the small hole in the relief valve body, and being unable to do so builds up a greater pressure, and thus forces increased quantities of oil to the main bearings, big end bearings, and so to the cylinders, pistons, etc.
It seems right to mention here that if plenty of oil is kept in the sump, it will take longer for that oil to be circulated through the engine. A small amount of oil is frequently passed round the bearings and quickly loses part of its lubricating properties. Moral — it is more economical and tends to better lubrication if the oil sump is kept well filled. Never allow the gauge to drop lower than ½ in. above the top of the brass tube. The sump is full when needle ceases to rise when more oil is inserted.
Every pump is tested at the works and is required to lift oil from a tank 15 in. below the pump, after the pump has been wiped thoroughly dry.
In case of trouble with the oil pump, we prefer you to return it direct to us, together with the timing case cover. Any defect can be rectified, and the whole assembly returned same day as received, if it arrives by parcel post.
If for any reason the pump is dismantled, the utmost care must be taken in re-assembling to see that a perfect face joint is made between the timing case cover and pump face. On no account put a joint washer or paint between the metal faces. After assembling it is also advisable to prime the pump with oil, leaving the left-hand (from front) union disconnected. Vigorously turn the engine until oil flows freely from pump. Connect up union and run engine gently for two or three minutes before opening throttle wide. Test pump also after cleaning out oil sump (see page 10).
Should your oil pump fail on the road, fill the sump until gauge rises to top, then insert another pint of oil. This will enable the big ends to actually dip into the oil and will allow you to continue your journey in safely if you drive steadily. Insert more oil at intervals of not more than ten miles, until journey’s end, or suitable garage available. We cannot accept responsibility for any damage accruing from the above suggestion, but put it forward as being quite safe if you make sure the big ends are dipping into the oil.
Particular attention is drawn to the necessity for copious lubrication of the dynamo shank gear bush, ‘the oiler for which is found just in front of the dynamo drive coupling. This gear runs in a very long bush and normally receives its lubricant from the timing gear case, but in a new engine with tight bearings it is somewhat difficult for the oil to reach this part unfailingly. It is therefore advisable to freely oil this bush via the oiler every time you start out, for the first few hundred miles, and daily afterwards until you are satisfied that the oil is reaching the bush from the engine.
A few drops of magneto or sewing machine oil should be inserted in oiler on front end of dynamo every 2,500 miles. Constant lubrication in quantities will cause trouble due to oil percolating from bearing on to the armature.
Give greaser one turn occasionally as required. Do not over-lubricate or grease will be forced into distributor case and cause misfiring. As the fibre on the contact arm wears, it will reduce the effective gap or opening of the platinum points. Keep adjusted to correct gap as per gauge on special spanner provided in tool kit. Diagnose misfiring when picking up to too small a gap and rectify accordingly.
The layshaft is placed immediately below the mainshaft, thus reducing. the amount of lubricating oil to be carried.
The correct level for oil is to half cover the lower or layshaft.
The measurement on a dip stick is 2 in.
Use Castrol D, or half D and half XL, melted up together. Don’t use grease. The tube let into the lid is an air release, to allow the air to expand and escape as the oil becomes warm in use. Don’t plug up. Examine oil level every 500 miles, and replenish to height indicated above.
The filler cap will be found on the lower right-hand side on aluminium differential case. The plug has been placed in this position to prevent over-lubrication. Remove plug and insert engine oil by means of an oil gun until oil overflows from plug hole. Replace plug. Examine every 1,000 miles. Don’t use grease. Test for oil level after car has been standing all night.
The rear wheel bearings are lubricated from the axle, but it is advisable to examine them periodically as per oiling diagram and pack with grease if necessary. We can supply hub drawer for this purpose at 7/6d. If too much oil is inserted in axle case it will be thrown out at wheel bearings. Avoid this by adhering to above instructions. (See Oiling diagram).
The front wheel bearings are packed with grease at the works, but they should be examined frequently and the quantity maintained (See Oiling diagram, also note in Chapter Six re hosing a car).
Valves — Spanners are provided in the tool kit to fit the two hexagons on end of valve stem. The clearance allowed is three-thousandths of an inch, or the thickness of a piece of tissue paper. To adjust valves, proceed as follows: Hold small or bottom nut, slack off large nut by screwing up ordinary right-hand thread. Turn small nut until required clearance is obtained, hold small nut and lock by large nut firmly in position.
The close adjustment of the valve clearance plays an important part in the power output of the engine and considerably affects the slow running. It also affects the quietness of the power plant. Adjustment should be made with engine hot.
The steering column will be found to enter the steady tube through two eccentric bushes (B). If, with front wheels held, play in excess of ¾ in. can be felt on steering wheel, adjust as follows: Slack off bolt on bottom of steering column where steady tube enters steering box. Grip the steady tube firmly with both hands and turn left or right as required to bring the pinion (A) on end of column, into closer engagement with internally toothed ring in steering box. Tighten up bolt.
Left: Steering Box Assembly
Foot —The operation shaft for foot
brake lies on the right side of gearbox and attached thereto. On this shaft is a short lever with return spring anchored to it. Slack off lock nut slightly and tap lever downwards until brake band is just clear of drum (see also illustration, page 8). Tighten up nut. If foot brake is inclined to be, fierce, remove band . and shape it in the form of a spiral, thus ensuring gradual action.
CLUTCH PEDAL AND FOOT BRAKE ADJUSTMENT
(Refer to diagram on Page 8.)
Turn nuts ‘D’ up or down to adjust tension of clutch (arrowed).
By slacking off nut ‘C’ clutch pedal can be adjusted to the most convenient position for individual taste.
Foot brake has Ferodo lining (arrowed ‘F’).
Insert screwdriver behind toggle ‘E’ and lever outwards until Ferodo grips the brake drum, then tap lever arm ‘A’ down until desired position of foot pedal is obtained and lock in position by nut and bolt ‘B’.
To adjust rear or hand brake for general. wear of brake linings, remove the board situated immediately under seat-back (squab) on two-seater and light four-seater, the middle board in front of rear seat in four-seater and saloon, and middle board in driving seat of long two-seater, when one large and two small brake operation levers will be found on a cross member tube. Slack off nut on large lever, place hand brake lever in the forward position on the ratchet quadrant, pull forward one or other of the small levers on the tube, until brake bands just commence to touch the brake drums, now lock up large lever and the brake will be found to be full “on” in the third notch on quadrant. (See illustration below.)
Above: Adjusting clutch and foot brake. Above: Adjusting handbrake.
If one side brake is inclined to act before the other and thus lock the wheel, slack the nut on small lever corresponding to the offending side and tap it round a little towards the rear of the car and adjustment will be balanced Then lock up nut as before.
SPEEDOMETER — See booklet supplied with car.
ELECTRICAL EQUIPMENT — See Lucas booklet, issued with car, also special chapter in this Instruction Book, explaining in everyday language the general principles of the various electrical units fitted. to our cars.
CARBURETTOR TUNING — See special booklet, gratis, issued with the car.
ADJUSTING MESH OF GEARS
If top gear is inclined to jump out of mesh, remove baseboards and gearbox lid. Slack off nut A (illustration below), push top gear dogs into complete engagement (as in upper sketch) by means of lever L, then, while holding gears in proper mesh, push gear lever G into top gear position until spring plunger is located in groove on underside of quadrant. Lock nut A and adjustment will be correct.
Act similarly to adjust first, and reverse gear mesh, but in this case slack off nut B and, of course, put gear lever G in first, or reverse position as required.
If one side acts before the other adjust the small lever ‘S’ of the offending side. Slack off nut ‘T’ to adjust brakes.
Clearance of the brake band is adjusted by the clip, ‘U’.
he JOWETT LIGHT CAR does not need an annual overhaul at great expense—quite the reverse. In fact, given reasonable usage, it should give several years’ service without a complete overhaul. The following information is given as a guide for the usual annual overhaul carried out by the owner in the winter months, or as occasion demands:
This operation is not usually necessary until at least 10,000 miles, if good oil has been used. Many cars exceed this mileage by 50 per cent. We particularly recommend you not to decarbonise after a short mileage just because it was necessary on your previous cars. Wait until the obvious signs of carbonisation make themselves evident.
The wide intervals between decarbonisations more than compensate for the somewhat longer time taken to decarbonise a JOWETT, as compared with certain other cars. For example, the majority of small four-cylinder engines need cleaning out every three to four thousand miles. If it takes a little longer on the JOWETT, at least it is only necessary at much wider intervals.
To remove the cylinders, proceed as follows:
1. Remove bonnet by unscrewing front attachment from underneath and sliding bonnet out from rear fitting.
2. Remove four water joints on cylinders.
3. Remove radiator, also starting handle if a two-seater or light four-seater.
4. Remove inlet pipe and carburettor, and all wiring on engine.
5. Slack off bolt on fitting at base of gearbox rear end.
6. Slack off nut on top of steering box and draw the whole column out by pulling the steering wheel upwards.
7. Slack off silencer clip at back of car and withdraw silencer pipes from engine flanges.
8. Remove torque bolts on each cylinder head (from front) attaching cylinders to chassis members. Disconnect foot brake-pull-rod and push foot pedal out of the way. Release gear selector rods and prop up starting handle tube about 3 in. until cylinders are clear of chassis side members. The engine can now be turned over to allow of the removal of one cylinder, which should be thoroughly scraped free from carbon deposit, using a blunt instrument, such as a screwdriver.
Now carefully cover piston sides and piston rings with a duster, leaving the piston head exposed. Carefully scrape carbon from piston head, taking care that no carbon is allowed to touch piston rings.
Thoroughly oil cylinder and piston, seeing that the gaps in the rings are not opposite one another, but equally spaced round the piston.
Replace cylinder, gently compressing piston rings as they enter the cylinder. Replace cylinder base nuts and proceed in exactly the same manner with the opposite cylinder.
If piston rings are bright all round and not stuck in their grooves, do not remove them, as the slight amount of carbon under each has gradually formed and taken up the wear. If it is cleared out the compression will be reduced, and the oil consumption probably increased appreciably.
It is usually advisable when decarbonising to examine the valves, and if necessary, to grind in the seatings with fine crocus powder, if not badly pitted, or carborundum powder, grade No. 220, mixed with a little paraffin, if deeply pitted, finishing with crocus powder. Thoroughly wash all traces of grinding compound away with clean paraffin before replacing valves, and take care to prevent compound from reaching cylinder walls.
Note re Decarbonising —The operation is simplified for the novice, if the whole engine unit is removed from the chassis. This, requires the help of a second person when lifting clear and replacing. With the engine removed, the beginner has a good opportunity of realising the construction of the unit, and with the experience thus gained, is able to decarbonise on other occasions without removing the unit, in accordance with the instructions given in the earlier part of this chapter.
Most JOWETT agents have a standard charge for decarbonising and grinding valves, cleaning out sump, etc. The. usual charge is 30/-, not a big sum to spend for attention after 10,000 miles.
It is unnecessary to remove cylinder to grind in the valves. Remove large screw on front mudguard and swing the guard upward out of the way. The valve caps can now be removed, giving access to valves.
It is probable that the valves will last as long as the car, breakages in these days of special alloy steels being almost unknown.
In the unlikely event of a broken valve spring, remove valve cap in cylinder head, using special spanner provided. Hold bottom nut on valve stem and slack off lock nut about two turns. (See illustration, page 7.)
Now insert screwdriver in slot on valve head and prevent valve from turning while nut and lock nut are removed from valve stem. The valve can now be withdrawn.
To insert valve— Hold valve-spring over spigot on water jacket base and
insert valve through cylinder head, passing stem through spring. Hold valve head with screwdriver, screw lock nut on valve stem and replace nuts as before. Adjust tappet clearance to three-thousandths, as previously indicated.
Every engine is marked for valve timing at the works in such a way as to obviate error in future. “0’s” will be found on the main timing or engine shaft pinion, also on intermediate or camshaft pinion. Place the “0” punched tooth on main timing pinion between the two dot punched teeth on intermediate pinion, and valve timing will be correct.
It is essential that the valve timing as sent out from the works shall not be altered in any way.
Top dead centre is found by a line scribed on flywheel. This line must be set opposite the centre line also scribed on flywheel housing. The flywheel mark will naturally come to the top for each cylinder in turn. Watch for the inlet valve of one cylinder just closing, then turn flywheel in direction of rotation until timing mark is at top. Now set distributor cam to be just breaking contact for that cylinder with ignition lever retarded.
Quick adjustment can be obtained by slacking front half of dynamo coupling, and with a gear engaged to hold engine steady turn the coupling on the shaft as required and thoroughly tighten up again. Do not attempt above unless you know what you are doing.
The dynamo runs in a clockwise direction seen from the front. If, therefore, the front coupling is slacked off, as explained above, the ignition will be advanced by turning the fabric coupling anti-clockwise, and retarded by the reverse movement. It should be noted, however, that the range of advance and retard provided by coil ignition is so great that it more than covers ordinary requirements, and alteration should only be necessary in the event of the front coupling having inadvertently slipped. This would, of course, have the effect of retarding the ignition point.
Do not attempt to alter ignition timing by moving the mesh of the distributor drive one or more teeth. Nor should you adjust by moving the cam on the make-and-break of the distributor. The only attention in respect of the cam should be to see it is securely locked by the nut on top of it. If this became slacked off by any means, you would find a mysterious absence of the spark at the plugs, due to the fact that the loose cam would not be turning, hence the make-and-break would not be operating — hence no spark. Check this over if ever you fail to get a spark at the plug.
The JOWETT clutch has long been famed for its remarkable durability and sweetness in action, if properly attended to when necessary. It consists of brass-bonded asbestos cord wound over grooves in the coned face of the clutch, drawn tight by three plates. It is almost impervious to wear and heat due to friction.
If it slips after changing up into second or top gear, try closing the throttle for a second, and then picking up in the ordinary way. If clutch now holds, the tendency to slip will be cured by oiling the clutch splines. Use a long spout oilcan and drop oil freely on centre of the tube A (see sketch page 10) passing across the hole in the flywheel housing. It will drop on to the clutch withdrawal race, and so to the clutch splines.
If no improvement, check oil level in gearbox. The splines are lubricated by the oil escaping from gearbox through the drilled first motion shaft, which is splined for the clutch. A low level tends to keep the splines dry. If still no improvement, increase the tension of the three clutch springs a little, by giving one complete turn to each. They will be more easily adjusted if sparking plugs are removed to release compression, thus making it easy to turn flywheel.
Adjustment for a fierce clutch is obtained in the first place by slacking off the clutch springs. If this does not effect a cure, insert powdered graphite by. means of an’ ordinary domestic knife, passed between the spokes of the clutch; and so as to deposit the graphite in the flywheel behind the clutch at ‘G’ in the sketch. About a dessert spoonful should be so inserted. Now start up the engine and gradually accelerate with the clutch engaged and gear in neutral. This will lodge the graphite on the inside of the flywheel and behind the clutch. Now, very gently, and very gradually, depress the clutch pedal with the engine running fast. The graphite will thus be allowed to gradually escape over the clutch lining and be deposited thereon.
General arrangement of gearbox and clutch.
An alternative method of graphiting the clutch face is to insert it by means of a thin, well worn domestic knife, at about six or eight places around the clutch, which is to be withdrawn by depressing the pedal for this purpose.
Do not run with a fierce clutch, which imposes a severe strain on the transmission, reducing the life of the cardan shaft joints, and eventually the pinion and back axle gears generally. Any tendency to slip after graphiting will disappear in a few miles. Repeat the operation whenever clutch becomes fierce, but three or four applications usually make a permanent cure.
The position of the clutch lever can be altered to suit the individual requirements by slacking off nut on base of lever and tightening up again after desired position has been obtained.
REPLACING FLEXIBLE DISCS
Universal joints have been replaced on the JOWETT LIGHT CAR by Flexible Discs, which are absolutely noiseless in action and require no lubrication. The normal life of the discs is about 10,000 miles front and 8,500 rear. To replace front disc, remove footboards, slack off nuts and gently tap out bolts from cardan shaft, allowing shaft to hang down. Now draw old disc off bolts on rear of foot brake drum, easing off each bolt a little at a time.
Gently work disc on to bolts in rear of drum until it is within three-sixteenths-inch of correct position. Now lift cardan shaft and. insert bolts through spider fitting on end, gently tapping them home through disc. As soon as bolts appear through disc draw completely home by turning all six nuts quarter of a turn, one after the other. Make absolutely sure all nuts are dead tight, and that each is fitted. with a spring washer. To replace rear disc, remove cardan shaft end first and allow to drop or tie up out of the way. Ease off disc and insert new one as before. Replace cardan shaft similarly and thoroughly tighten all nuts.
Examine bolts for tightness periodically, as a slack bolt destroys the disc in a very short time.
REPLACING BRAKE BANDS
HAND — Jack up car and remove wheel. Extract split pins from toggle and slide brake-band off. It is a moment’s job to fit the new brake-band and insert split pins. Adjust the lock nut on centre of band to just keep it clear of the. drum. Replace wheel.
This operation for both wheels can be done by a novice inside twenty minutes.
The average life of a brake lining is at least 15,000 miles.
FOOT — Remove footboards. By extracting split pins it will be found that the old band can be removed at once and new one fitted in five minutes.
We advise the purchase from us of a complete brake-band with lining, as the prices charged are no more than those of the lining for other cars. This saves you time, and the purchase of special tackle for the job. If you have the tackle, of course you may prefer to do it yourself. We make the suggestion with a view to avoiding delay, or possibility of garage charges for a very simple operation, usually avoided by most owners. You can buy linings locally, but we supply complete bands only.
If for any reason it is necessary to remove the gearbox, this should be done as follows :— Pull hand brake hard “on,” place the jack under rear of oil sump and screw up until the top of the jack just commences to exert pressure on the sump casting. Remove foot brake pull rod, to enable foot pedal to be put where required, also gear selector rods. Then disconnect front universal joint and drop cardan shaft out of the way. Now remove bolts holding gearbox to engine, also slack nut on one at rear of box on cross ‘tube, and the gearbox will come away easily.
Replace in reverse order.
CLEANING OUT OIL SUMP
Remove suction pipe from near side of engine, also two nuts from suction casting at lower end of said pipe, and gently lever the casting away from the sump. A conical gauze will be found soldered to it on the inner side, which must be thoroughly cleaned out in paraffin at the end of 1,000 miles and every 5,000 afterwards. Also drain out all old oil by removing plug under oil sump, wash crankcase out with dean paraffin, replace plug and suction casting, taking care to fit the latter right side up as marked, otherwise oil will not circulate.
The oil pump must always be tested before running the engine after the oil sump has been emptied, in case it fails to lift the new oil in the sump. Proceed as follows: Remove left-hand union nut on oil pump and vigorously turn engine with ignition switched off.
If oil is pumped out everything is in order, replace union nut and pipe and proceed. If the oil fails to appear, remove right-hand union nut on suction side of pump and fill the pipe with ‘oil, also inject a little into the pump itself, reconnect the pipe to the pump by means of the union nut and again test for oil delivery by turning engine as before.
This is purely a precautionary measure, but must be carried out after draining the sump for any reason whatever.
ADJUSTING STARTING HANDLE
The most convenient position for any individual driver (according to height) can be obtained in two minutes.
Slack off nut on starting handle just sufficient to allow handle to turn on its shaft without turning the engine.
Pull handle gradually round against the “feel” of the compression until best position is obtained, and thoroughly tighten up the nut. We find about 7 to 8 o’clock suits the majority of owners, but small drivers prefer the full compression to be felt at a position corresponding to about 9 o’clock.
GENERAL CARE OF COACH WORK AND FITTINGS
othing detracts from the second-hand value of a car so much as neglected coachwork and upholstery. Remember that a car which has been well looked after, sells for much more than one that has obviously been neglected.
In dropping the hood, run the fingers round the folds and see they are not “puckered.” Strap the hood down when not in use and thus avoid chafing of the fabric. Always leave the hood up to dry after rain or wipe it down before folding. It dries easily in one night.
Always keep side curtains in holders provided when not in use. Take care not to nip the hood material in lid of dickey seat when closing same, or between fittings of light four and four-seater. Do not pack angular or bulky parcels between folds of hood.
Do not allow mud and dirt to thoroughly dry on body. Use a hose before it becomes set. Finish off with a soft sponge, followed by a clean wash-leather.
WARNING RE USE OF HOSE
Although provision is made to exclude water from the front and rear hubs, it is impossible to guarantee them as watertight against a stream under pressure. When using a hose, therefore, avoid playing the jet of water direct on to the inside faces of the hubs.
Nothing ruins a ball race so quickly as rust, and this is inevitable if water is forced in under as much as 20 lbs. pressure by means of a hose.
We can recommend the use of a good coach paint preserver, many of which are now marketed.
Left foot on running board, right foot on dickey step provided, is the correct way into the dickey seat, and it avoids kicking off expensive coach enamel.
We feel it necessary to qualify the above remarks by stating that the JOWETT is made of the very best materials obtainable; and holds an enviable reputation for high second-hand value. We have kept a record of JOWETT cars advertised for sale, and the depreciation after one year averages 12 to 20 per cent., whereas most cars depreciate anything up to 25 — 45 per cent. in the first year.
Until many thousands of JOWETT cars were on the road, we kept careful records of all spares and replacements sent out for each car. We cannot keep these records up-to-date now because so many of our clients fail to quote the car number when ordering spares. We have, however, amassed a fund of information concerning our cars during the sixteen years they have been before the public in their present form, and this has enabled us to eliminate those minor defects so prevalent in cars of recent origin.
We desire you to appreciate that we do not lose interest in our cars, however old,. and you will assist us to keep our records and to help you more unfailingly by always quoting your car number in every communication addressed to us. The J0WETT is a car with a brilliant past, and we hope for, and are endeavouring to make sure of, a still more brilliant future.
CARE OF TYRES AND TUBES
e offer to Messrs. Dunlop this compliment, that at no time in the history of the JOWETT car has any other tyre equipment been standard.
We can thus state our entire confidence in these characteristically British products, and when we indicate that a certain mileage per tyre can be expected, we speak from twenty-one years’ experience of that firm’s tyres.
But to obtain that mileage, certain obvious attentions must be afforded them, which are simple and occupy no more than a few minutes at comparatively wide intervals.
You can rely on at least 10,000 miles per set of high-pressure tyres on any model JOWETT if you do not overload your car, and drive reasonably when cornering. The two-seater and light four-seater models will easily exceed this figure, often approaching 15,000 and sometimes exceeding that when carefully used. These figures refer to total mileage per set, individual tyres in some cases greatly exceeding the average figure.
The balloon, or low-pressure tyres, which are fitted as standard, are giving average mileages greatly in excess of this. We anticipate, in view of our experience to date, that not less than. 16,000 miles will be obtained. My own four-seater, with a special saloon top, completed 18,000 miles on Dunlop balloons, and they were not by any means kindly treated, being used over all sorts of tracks, in out-of-the-way places.
The following hints regarding tyre maintenance are in addition to any issued by the manufacturer.
High-Pressure Tyres.—It is impossible to give correct inflation pressures because of the varying load carried• by different owners. On the other hand, it is well to remember that inflation pressures quoted are often too high for the JOWETT because of its appreciably lighter weight. We find 25-28 lbs. front and 30-33 lbs. rear quite suitable for a two-seater with two normal passengers, and a reasonable amount of luggage. A check we often employ is as follows: Pressure is about right if the width of the tyre where it meets the road is 1 in. greater than the width at other places. This applies to all weights.
The above will give a general guide as to pressures, but it is insisted that responsibility rests with the owner at all times, as he only, knows the loads carried and general conditions.
Care should be exercised to see that equal pressures exist in the front tyres as a pair, otherwise steering drag will take place in the direction of the softer tyre. Similar remarks apply to the rear pair for equally obvious reasons.
Periodical examination for small flints embedded in the tread of the tyres will well repay the time occupied, and any sand blisters—which often develop when the tyre is nearing its “end”—should be cleaned out, and the tread either hot or cold vulcanised on to the wall to prevent the ingress of further sand or equally destructive water.
For this purpose the handy vulcanisers, now so popular (and cheap), are a great boon, and can be used without any previous experience. Once a year tyres and tubes should be removed from the wheels and one coat of anti-rust paint applied to the rims. Then sprinkle French chalk on the inside and bead of tyre before replacing. If you have a puncture, always see that a patch is placed inside the tyre (outer cover) if the place can be found where the foreign matter entered. This precaution will keep out water, grit, etc., and prevent the fabric walls of the cover from further deterioration. In case of a bad cut, return the cover to Fort Dunlop, or a good local repairer for careful attention in this matter.
Attentions similar to the above may occupy two or three hours in the course of a season, but will repay the time and effort fivefold.
Balloon or Low-Pressure Tyres — All the above remarks apply to the low-pressure tyres, with the exception of the suggested pressures—these, of course, may be considerably less. As little as 13 lbs. front and 15 lbs. rear has been found quite suitable for normally loaded JOWETT cars, because of their extreme lightness; but, again, these pressures must not be accepted as correct for your purpose without careful checking.
Low-pressure Dunlop tyres have one inestimable value, not characteristic of most other low-pressure tyres, in that they are practically straight sided — a type of construction which makes it impossible for the tyre to leave the rim in case of a burst. This feature adds greatly to the safety of fast motoring, and, in addition, allows more use to be made of the possible low-pressures without danger of the tyres creeping on the rims.
We have also been informed (although we cannot speak from personal experience) that low-pressure tyres run at 30 lbs. pressure (i.e., about that used for high-pressure tyres on a JOWETT) give quite phenomenal mileages. This may be worth trying by owners whose running is confined to roads with very good surfaces, and where the comfort characteristics of the tyres are not required.
Like all other good things, there is one little snag which it is impossible to overcome at present. That is a tendency for mild wheel wobble under certain conditions where regular inequalities of road surface occur, such as large sets or regular corrugations caused by heavy traffic.
This wobble is easily overcome by either of two methods. If the steering is turned either right or left, as may be possible at the moment, it disappears. Alternatively, if the speed of the car is altered, either faster or slower than the speed at which it occurs, it will also disappear.
One final suggestion re low-pressure tyres:
The low inflation pressure allows the tyre to roll over somewhat when cornering. This inclines to wear the outward half of the tread more quickly than the inner half. It appears worthy of consideration, therefore, to periodically change the tyres from left side of car to right, and vice versa. A little point, if you will, but still tending to further economy.
NOTE:— Messrs. Dunlop advise higher pressures for all their tyres, than those quoted above. They maintain that our pressures are too low, but we give them in the light of wide experience, and a knowledge of the full facts of the case. We have never received any complaint from JOWETT owners on this point, but feel compelled to indicate the position in justice to Messrs. Dunlop.
CHAPTER EIGHT, being an effort to instruct the absolute novice in the principles of the
ELECTRICAL SYSTEM (see diagram, page 13).
The following notes on the care and maintenance of the electrical system are given as a general guide. They should be read in conjunction with the booklet supplied with each car.
No section of the car’s anatomy gives a greater return for regular attention than the electrical equipment.
Briefly analysed, the system consists of a dynamo which produces electrical energy and stores it in a battery for future use.
The wiring may be considered as the pipe lines by means of which that energy is carried from the storage tank or battery to the various places where it is to be used for lighting, engine starting, or ignition. It will, therefore, be obvious that the connections or terminals of all wires (or pipes, as we considered them) must be tight, and they should be examined periodically to see that this is the case.
We shall now endeavour to find out the functions of the various components and trace out the course of the electrical energy or current from the battery in each case.
SWITCHES AND CONTROLS
All operations in the control of the electrical system are carried out by pressing one or more of the buttons or switches fitted to the instrument board of the car. This we shall call the control station, and to these switches come supply pipes (or wires) from the storage battery. The switches then become taps by means of which the current can be directed to any part of the system at will.
THE ENGINE STARTER
The starter is an electric motor fitted alongside the gearbox in such a manner that as soon as the motor is made to turn (by supplying electric current from the storage battery) the pinion on the motor shaft moves forward into engagement with teeth cut on the flywheel rim. The circuit for the starter motor then consists of. a pipe (wire) from the battery to the motor, one from the battery to the switchboard, and one from the switch to the motor.
Turn on the tap (switch) and the circuit is complete, i.e., the motor revolves.
That’s simple, isn’t it?
Now let us trace the next electrical circuit, which ignites the petrol mixture in the cylinders and is referred to as the
We have here, firstly, the storage battery, or cistern if you will, connected by pipe lines (wires) to the ignition switch, through the coil and distributor and so to the sparking plugs. Let us try and follow it out. The type of current required to jump the points of the sparking plugs is of a different type to that used for the starter motor. We refer to it as high tension current, and to transform it from the type stored in the battery, which is low tension, it is sent through the COIL, which acts something like a service tank of water placed at a considerable height.
You know that for every 2 feet that water is placed above the point at which it is required to be tapped off it exerts a pressure of 1 lb. per square inch.
Now, without entering into a long electric explanation, the COIL has the effect of raising the pressure of the current in much the same way as the tank situated at a considerable height.
We have now got our current from the battery through the ignition switch to the coil, increased its pressure, and must next deliver it to the cylinder at precisely the correct moment to fire the mixture by jumping across the plug points.
For this purpose, a DISTRIBUTOR is fitted to the DYNAMO and driven at a pre-arranged speed by the engine. Down the centre of this distributor we take the current under pressure from the coil, and as the revolving arm fitted to the interior comes opposite one or other of the points connected by wires to the sparking plugs, the spark jumps across a small gap, runs down the wire, across the plug points, and so to earth via the frame or chassis, which is like running the used water to earth or into the drain.
That is a somewhat intricate system, but is really straightforward if followed point by point.
Now we can turn to the LIGHTING SIDE and once more we are on simple ground. From the storage battery, via the lighting switch to the LAMPS, the low tension current is taken, thus heating the filaments of the lamps, and there you are!
From the foregoing you will see that in each case the battery is called upon to supply the three distinct systems of STARTING, IGNITION and LIGHTING with electric current received from the DYNAMO, which is the source. Little trouble is to be expected here if the makers’ instructions are followed, but in the case of the battery, attention at regular intervals will be amply repaid, and we therefore append the necessary information in the hope that you will realise for every ten minutes you spend on its proper care you will obtain hundreds of miles of worry-free service.
CARE OF BATTERY
The attention necessary can be summed up in the four following rules: —
1. Keep connections tight and the battery clean. (A smear of Vaseline on the terminals will prevent corrosion.)
2. Take frequent hydrometer readings or get your garage man to do so.
3. Unless acid has been spilled, add nothing but pure water, but do it often, to keep the level ¼ in. above the top of the plates.
4. If hydrometer readings differ for each cell, acid is probably being lost by a leak and must be investigated. Correct specific gravity for replacement acid, 1.225.
CARE OF DYNAMO
1. Lubricate as a magneto, i.e., a few drops of magneto or sewing machine oil every 2,500 miles. Do not flood.
Do not confuse this lubricator with greaser for distributor shaft.
2. If dynamo stops charging look first at the fuse, fitted behind the switchboard. If blown, replace with spare wire supplied in a small holder, after you have investigated cause of fuse blowing. (See Lucas handbook.) See also notes at end of this chapter.
3. If fuse intact and still no charge shown on ammeter, examine brush gear on rear end of dynamo. (See also Lucas handbook.)
CARE OF DISTRIBUTOR
1. Give greaser half a turn weekly. Do not confuse this greaser with lubricator for dynamo bearings.
2. A little smear of grease on the fibre in contact with cam on centre pillar will prevent undue wear.
Don’t use oil.
3. The contact points should be adjusted periodically, so that when fully open the gap gauge supplied can just be inserted.
4. During damp weather remove distributor cover and wipe any accumulation of moisture from inside, as this will tend to cause misfiring.
ELECTRIC STARTER MOTOR
1. Keep all connections tight. Examine weekly.
2. If, in starting, bendix pinion is thrown into mesh with teeth on flywheel, and having failed to start engine, sticks in mesh, give one sharp turn to starting handle and bendix pinion will immediately free itself. A little powdered graphite on the bendix screw will cure this tendency to stick. Don’t use oil.
3. Always retard ignition when starting engine, then advance for general running.
4. Do not hold starter switch “on” if engine refuses to be turned over, release and quickly press in again, when the starter should bump the engine over compression.
5. If starter refuses to turn engine as above, battery needs charging. The starter button should only be pressed momentarily, as the discharge through the motor is heavy. If engine fails to start easily, investigate the cause. Start engine by crank and give dynamo the opportunity of charging battery by not using starter for a time.
The diagram below explains the remarks contained in this chapter and will assist you to appreciate the functions of the electrical outfit, after which, in conjunction with the Lucas manual, you should be able to efficiently maintain the car in good condition indefinitely.
DIAGRAM OF ELECTRICAL CIRCUITS
DYNAMO (DY) generates electricity, which is stored up for use in BATTERY (B).
IGNITION. Current tapped off by switch (S1) passes through COIL (C) to DISTRIBUTOR (D) and by means of revolving arm (A) is passed to one PLUG (SP 1) and in turn to the other (SP 2).
STARTING. Current tapped off by switch (S2) turns the STARTER MOTOR (SM) and pinion is flung forward into mesh with FLYWHEEL, turning same and starting the ENGINE.
LIGHTING Current tapped off by switch (S3) which has two positions (bright and dim)
N0TE — It is to be understood that S1 and S3 are mounted on body of switchboard, S2 is fitted independently on facia board.
The latest JOWETT cars are fitted with a dynamo, the output of which is controllable from the switchboard.
Ours is the very first light car in the world to be so equipped.
This control enables the driver to maintain a full charge in the battery at all times, without overcharging, which only wastes the electrolyte by evaporation.
The half-charge position will be found to cover normal requirements, unless much starting and stopping is done.
Full charge will probably be required for winter driving or to boost up the battery in a short time when required.
There is nothing to go wrong with this device; it is the simplest arrangement imaginable, but unique in its usefulness, and characteristically JOWETT
A FEW POINTERS ON THE ELECTRICAL SYSTEM
The rate at which the dynamo charges the battery under running conditions is, of course, a moment of the back E.M.F., and is in consequence dependent on the condition of the battery at any given time.
The following data will, however, prove of some interest, and although not “electrically” correct, is nevertheless sufficiently accurate for general use.
Car on top gear, switch in “full charge” position.
NOTE: Table is located on next page.
Net dynamo output to battery at (road speed):
= 3 amperes
= 5¼ amperes
= 6¾ amperes
= 7½ amperes
= 8 amperes
= 8¼ amperes
= 8¼ amperes
= 8½ amperes
The dynamo actually produces about 2 amperes more than the above figures at all speeds. This is used for the ignition, and is not shown on the ammeter, which only registers net input or discharge, as the case may be.
Taking head and rear lamps as consuming 4½ amps., the dynamo will balance the battery discharge at approximately 16½ m.p.h., say, for safety, at 20 m.p.h.
If, therefore, an average speed of 20 m.p.h. or rather less is maintained when night driving the lights can be indefinitely maintained.
With the battery in the charged condition, and dynamo not running, the dim lights should be maintained for about 12 hours. They rarely last so long on continuous discharge, but there is evidently ample reserve for emergency.
Battery capacity should be halved when computing continuous discharge, hence a 65 ampere hour battery can be reckoned to give somewhere about 33 ampere hours for continuous, but for intermittent or ignition discharge will give about its full rated capacity. It will, therefore, be seen that a fully charged battery will run the ignition set for a very long time and has therefore a big margin of safety.
All the above notwithstanding, avoid ever running the battery in a semi-discharged condition, as the life will be reduced in consequence.
If the battery is found to be low and it is necessary to drive in the dark, run engine fairly fast in neutral for a few moments with lights switched off. You can then carry on, and a certain amount of second gear running will also help to charge battery quickly. But take earliest opportunity of investigating reason for low condition of battery.
NOTES In case wires are ever removed from the lamps, the following is the correct attachment: Black wire earthed to body of lamp; red wire under one spring plunger; blue wire under other spring plunger; any other order of attachment will completely run the battery down in a short time.
Too wide a gap at the sparking plug points uses more current to operate than is necessary.
Coil ignition functions well with a single point plug. An expensive, heavy electrode, three point plug is unnecessary, but, of course, may be used.
If both dim and bright filaments of a lamp burn out, be sure you have a bad connection somewhere. Examine terminals on battery, positive and negative wires on lamp, and earth wire from base screw of coil to the bolt on the flywheel case. This earth wire is particularly important. Always see that it makes good electrical contact with the engine or flywheel case.
The following article, by the present writer, was published in the Light Car and Cyclecar, April 18, 1924. None of the arguments were refuted or even questioned by the readers. It seems worthy of inclusion here, since it indicates many interesting facts concerning coil ignition.
BATTERY AND COIL VERSUS MAGNETO IGNITION STARTING UP WITH A TOTALLY DISCHARGED BATTERY
A STRONG CASE FOR THE COIL
“Coil Crank’s” letter in your issue of March 21st draws attention to the impression that the use of coil ignition makes one liable to be stranded. It is quite time that someone exploded this myth and so placed the coil system nearer to the place in the esteem of motorists in general which its many advantages over the magneto obviously qualify it to occupy.
The better-known advantages are as follows : (1) Intense spark at the very lowest engine speeds, thus ensuring au almost unfailing start on the coldest morning. (2) Presuming the presence of an explosive mixture in the cylinder, there is no necessity to swing the engine—a pull-over compression is sufficient. (3) Where a starter is used, the drain on the battery is very much less than with magneto ignition because of the intense spark, as in No. 1, and the life of the battery is thereby considerably extended. (4) Largely increased range of advance and retard, with consequent saving of petrol at high engine speeds, and sweeter running over the lower range.
Fig. 1.—If cell B is dead, short circuit the cell by a wire as shown in sketch. If cell C be defective, connect wire from negative on B instead of negative on C. If A be defective, take wire from positive on B instead of positive on A.
The only serious and persistent criticism levelled against the battery-coil system is that, in the event of battery failure, the car will be stranded. It is just here that the mistake is made.
There are two main headings under which battery troubles may be grouped :— (a) Complete and absolute failure; (b) partial failure due to mechanical breakage affecting one or more cells, or the battery being in a discharged condition as a whole or as to one or more cells.
Now it is exceedingly difficult to see how condition (a) can arise, short of the battery falling off the car and being lost entirely; such an eventuality is no more worth consideration than the question as to how to get home when the engine falls out of the frame. Such things do happen— but not frequently.
In the case of condition (b) it is a simple matter to cut out the defective portion of the battery (see Fig. 1), and the ignition will work quite satisfactorily on four volts in the case of a 6-volt equipment, or on eight volts in the case of a 12-volt set.
When the battery has become completely discharged due to a short circuit or other cause, it is always possible to start the engine by hand. The ignition and all other switches should be turned off and the battery allowed to rest for a quarter of an hour.
A temporary connection is made by means of a length of wire or a coin, between the resistance unit cover (A) and the terminal (B) on the coil (see Fig 2) The ignition is then switched on and the engine started by hand and run up to a speed at which the dynamo commences to charge— the dynamo switch being, of course, put on. So soon as charging commences the wire or coin should be removed and the journey commenced. The speed of the engine should not be allowed to fall below that at which the ammeter shows the dynamo to be charging.
A mile or two on second gear will bring the battery up sufficiently to allow of normal operation. Naturally, the starter should not be used until the battery has been fully charged, which operation should be carried out as soon as possible.
The above points show that, at the worst, some small inconvenience may arise as a result of an accidental short circuit or gross neglect of the battery.
Few cars exist to-day which have not dynamo lighting. This necessitates the carrying of a battery, to maintain which in efficient working order a certain amount of regular attention is necessary, and should be forthcoming from every motorist, if only in the interests of economy.
This attention consists of examining weekly the level of the electrolyte in the cells and replenishing with distilled water when necessary. Taking the specific gravity of the electrolyte by means of a hydrometer about once a month is also recognised as a necessary precaution.
These small attentions at regular intervals ensure carefree service and considerably extended battery life. They are necessary on the part of the owner of a car with magneto ignition, therefore there is no increased onus in the case of the man whose car has battery-coil ignition other than the fact that the former relies on his battery for starting and lighting, whereas the latter uses it also for ignition, an increased drain of approximately two amperes, which is easily provided for by the maker, who supplies a bigger and usually better battery for the purpose.
I cannot confess to a great amount of sympathy with the owner who finds himself with a completely run-down battery these days, when charge and discharge-indicating ammeters are fitted on all good cars in a position within view of the driver, who is thereby enabled to know the input to his battery, and, when his engine is stationary, the drain of the lighting on it.
If an ammeter shows a discharge with lights off and engine stopped, it indicates a “short” somewhere, and steps should be taken to find and cure it. If his ammeter does not register a charge when the car is running on the road (above, say, 12 miles an hour), a driver guesses either a “blown”
Fig. 2.— How a start can be made even when the battery is totally discharged.
fuse or a stuck-up dynamo brush, and acts accordingly. If he notices nothing, arid consequently does nothing—well, he pays for it, and it is difficult to legislate for him by safeguards other than those already provided.
In conclusion, I would point out that the latest improvement to be standardised on a popular horizontally opposed-engined car goes still further to reduce the already small amount of attention required by the modern battery. I refer to the dynamo-output control incorporated with the ignition switch, whereby either half or full dynamo charge is available by the upper and lower switch positions respectively. This allows persistent overcharging to be avoided, with consequent diminution of evaporation of the electrolyte, and is, I venture to think, a feature that will be found on all future cars, although it has hitherto been confined to cars in the luxury class.
Bradford. H. G. MITCHELL.
THE JOWETT GUARANTEE
e give the following guarantee with our Motor-Cars instead of the guarantee implied by statute, or otherwise, as to the quality or fitness of such machines for the purpose required; any such implied guarantee being in all cases excluded. In the case of cars which have been used for “hiring out” purposes, no guarantee of any kind is given or is to be implied.
We guarantee, subject to the conditions mentioned below, that all precautions which are usual and reasonable have been taken by. us to secure excellence of materials and workmanship, but this guarantee is to extend and be in force for six months only from the date of purchase, and damages for which we make ourselves responsible under this guarantee are limited to the supply of a new part to replace that which may have proved defective. In the case of a purchase through an Agent, the guarantee dates from the day of delivery to the purchaser, providing the car has not been used in the meantime. We undertake, subject to the conditions mentioned below, to make good at any time within six months any defects in these respects. As Motor-Cars are easily liable to derangement by neglect or misuse, this guarantee does not apply to defects caused by wear and tear, misuse, or neglect.
CONDITIONS OF GUARANTEE
If a defective part should be found in our Motor-Cars it must be sent to us by passenger train, carriage paid, and accompanied by an intimation from the sender that he desires to have it repaired free of charge under our guarantee, and he must also furnish us at the same time with the number of the Car, the name of the Agent from whom he purchased, and the date of the purchase. Failing compliance with the above, no notice will be taken of anything which may arrive, but such articles will lie here at the risk of the senders; and this guarantee and any implied guarantee shall not be enforceable.
We guarantee only those Cars which are bought either direct from us or from one of our duly authorised Agents, and under no other conditions.
We do not guarantee the specialities of other firms, such as tyres, lamps, electrical apparatus, etc., supplied with our Motor-Cars or otherwise.
THE TERM AGENT
is used in a complimentary sense only, and those firms whom we style our Agents are not authorised to advertise, incur any debts, or transact any business whatsoever on our account, other than the sale of goods which they may purchase from us; nor are they authorised to give any warranty or make any representation on our behalf other than those contained in the above guarantee.
JOWETT CARS LIMITED.