Letters from Readers, January 1966

N.B. —Opinions expressed are those of our Correspondents and “Motor Sport” does not necessarily associate itself with them.— Ed.

Mini v. Imp

Sir,
I strongly agree with the Mini v. Imp observations made in the November issue (name and address supplied), Perhaps Hillman Imp enthusiasts are sensitive to the apparent tendency to “knock” this car in the Press and elsewhere, but many readers will share the view that the Imp has received more than its legitimate share of criticism. I was amongst those who became intrigued by Imp engineering and decided to buy. Although oversize for this car (6 ft. 4 in.), I took delivery in August 1964 with the intention of enjoying a few months’ driving before getting a car more closely in line with family requirements. After thorough and restrained running-in, my Imp was driven hard for 10,000 miles during nine months’ ownership. My views and experiences may be of interest :

Faults on Delivery;
None, except “balanced” wheels grossly out-of-balance.

Faults in ServIce,
1. Gearbox; At 5,000 and 10,000 miles minor faults in otherwise excellent box. Jumping out of 3rd on overrun, roughness on quick 3rd/top changes.
2. Exhaust valve; One valve burnt badly at 10,000 miles; most likely from incipient fault, since remainder in good condition. Auto-choke reputation led to incorrect initial diagnosis of cause of rough running. (On the whole choke worked well for me, engine being notable for no-hesitation pulling from cold in all weathers. I was nevertheless suspicious about mixture strength at times.)
3. Flasher cancellation; Failed at 6,000 miles.
Rootes most helpful in dealing with the aforegoing shortcomings. Water pump and carburetter replaced for latest type although both operating satisfactorily at time.

Controls
With the seat frame back dropped 1 1/2 in., I found the driving position comfortable for up to four hours’ continuous driving. For me, layout of minor controls was near ideal, with most requirements at finger-tip range. I should have liked the flasher stalk to have moved in the same relative direction as the horn stalk. (Latter too embarrassingly “Noddy” to he usedl)
Wipers satisfactory for tall driver but my washers frequently blocked with residue in system from purchase.
The heater is simple and effective. although the temperature control lever is over-sensitive.

On the Road
I found the Imp a delight to drive under all conditions except in high winds, when the car proved a “pig” to keep on a chosen course.
Combination of smooth and direct foot controls, quick precise gearbox, light and accurate steering gave me great pleasure. With tyres regularly at 20 front and 32 rear (C41), handling was entirely predictable, not least during fast cornering. When eventually the rear end moved, the breakaway was gradual and easily corrected. Cornering performance in the wet was undiminished and its behaviour just as gentlemanly. (Was it not you, Sir, who said it was difficult to establish whether the Mini or the Imp cornered better without consecutive tests wearing “go-faster gloves”?)

Consumpton
Petrol; 38 m.p.g., overall with main road/motorway cruising 70-75 m.p.h., and generally full use of gears when accelerating.
Oil; 600 m.p.p. at 10,000 miles and falling steadily.
Water; Nil. No sign of early coolant troubles.
Tyres; 50% worn at 10,000 miles. Even wear obtained by move rounds at 2-3,000-mile intervals.

In conclusion, I was never more reluctant to sell a car and would have liked to have kept it for No.2—often No.2. I should like to know whether other readers can put forward reasons for the apparently slow growth of enthusiasm for the Imp. I may be prejudiced but I know of many Mini owners who were less pleased with their first 10,000 miles.

Liverpool. A. Colman.

Sir,
I have been interested by the correspondence relating to the Hillman Imp in your November issue. It was with certain reservations that I took delivery of a Singer Chamois in replacement of my 1964 1 1/2-litre car, in May. (I wished for more sound insulation and the SP41 tyres of the Chamois.)

After 5„000 miles, one water pump and a trans-axle oil seal (500-mile service), I am highly satisfied with this car. Apart from the two points just mentioned and a heater blower which was not connected on delivery, there have been no teething troubles whatever. The little engine is completely untemperamental, has never missed a beat, and seems smooth and extremely lively. Starting is instantaneous. A little oil was used during the first 3,000 miles but this has now decreased to an almost negligible amount, as mentioned in the handbook. Petrol consumption to 4,600 niiles averaged 45.6—I am light-footed but not a dawdler!

The car can show a clean pair of heels to just about anything of its capacity unmodified, and to a good deal of even heavier machinery. I have seen an indicated 90 m.p.h. on the speedometer on M1 (the wind must have been following us) and at this speed the car felt quite stable and the engine like a turbine. My more normal cruising speed is from 60-65 m.p.h. when the car feels to be completely unstressed and there is a high standard of quietness for such a small car. Oddly enough there is no wind noise.

Handling and stability are very good indeed and the car can be cornered with great confidence—I have never experienced any suggestion of tail heaviness and were it not for the sound of the engine from the rear it would be difficult to realise it was rear-engined. I think the SP41s help here.

General design appears to have had careful thought. I am 6 ft. 2 in. but have no difficulty in fitting in comfortably with the seat well back. The accelerator position can be rather tiring on long journeys, although I understand this has now been modified. Instruments and controls are exactly where required and the gearchange is a delight.

The brakes on my particular car are adequate but less smooth under hard application than I like. I have a feeling one of the rear drums is not quite true, though I have so far been unable to convince my dealer or this.

After 29 years’ driving I can say that this is truly one of the cars I have enjoyed driving most and it could never be regarded as dull. Never a drop of water has found its way inside—even during our last summer!

Sheffield. “C.T.B.”

Sir,
I feel bound to comment on the letter from a correspondent in your November issue. I have sat in an Imp far too long to let his lack of understanding as to why so many people have criticised this car continue any further.

My Imp was purchased in December 1963. The early faults were small. Namely, the sun visor worked itself free very rapidly, several chromium parts had to be replaced after inspection by Rootes, rust formed within weeks on various parts of the body, and leaks developed round the bonnet hinges. Fuel consumption, never above 34 m.p.g., fell to 24 m.p.g. over several thousand miles. The pneumatic throttle had to be replaced. At 1,400 miles the clutch failed. At 18,200 miles the water pump packed up. One would have thought that the replacement parts would have lasted longer, but the clutch again failed at 26,500 miles, and the water pump at 24,700 miles. The latter involved me in delay for a day and a hotel bill, in which Rootes were not interested.

Both king-pins were replaced within the first year of use, as were the silencer (fractured rear bracket) and automatic choke. After indifferent performance which my then garage seemed unable to cure, the carburetter was replaced.

My next purchase will not be a Rootes product. This is unfortunate since I have many pleasant memories of the 1930 16/20 Humber tourer I formerly owned.

Cuddington. L.G. Machin.

Sir,
Your un-named correspondent last month criticises those who run down the Hillman Imp and, never having owned one himself, goes on to praise it to the skies. May I, as an owner, be permitted to redress the balance with an account of my own experiences which, from inquiries among friends and acquaintances who also possess this model, I gather to be far from unique. I purchased the car in April 1965 and it has been a continual source of trouble ever since. Your correspondent blandly asserts that the early trouble with the automatic choke has now been sorted out; nothing could be further from the truth. Despite repeated adjustments it has never functioned properly. This, however, is a small matter compared with that which followed. In early September; with the car barely five months old, I suffered a complete mechanical breakdown; the cause of the trouble—a common one in this model, I have since learned—was traced to the gearbox. As if this in itself were not bad enough, I was told that spare parts took upwards of a month to deliver and that I should reckon on being without my car for several months. It was only by dint of almost daily ‘phone calls to Rootes’ Head Office that I eventually got it back in just four weeks.

My troubles were not yet at an end, however. A week ago I again had a complete breakdown, the trouble this time being with the clutch.

I consider this car to be an absolute disgrace and its bad reputation, which your correspondent finds so hard to understand, fully justified. However, if he is still an enthusiast, perhaps he would care to have my Imp ? I can assure him that no reasonable offer will be refused.

Guildford. M.G. BROWN.

Sir,
I, in common with one million others, own a B.M.C. Mini. For the price of £470 I think it is an exceptionally good car. The reliability has been proved over 21,000 miles since February 1965. There are, however, two lamentable exceptions : the suspension, which in my opinion has made fast cornering unnerving for passengers (it also collapsed on both sides two weeks after delivery), and the water pump, which gave up the fight at 17,000 miles. My eager neighbours call round to see when the gearbox is going to break up, the doors fall off, or the engine lock up solid, but so far in vain. My own car is very noisy inside; the 650-c.c. Triumph Bonneville motorcycle that I used to own did not tire me so much.

I have managed to improve the top speed and acceleration to Imp/Hornet standards by fitting a Derrington exhaust/inlet manifold, and one stage richer needle for the carburetter. The car is at present running on Dunlop SP41 tyres, which I find very durable and predictable.

Warnham. J.D. Walton

In defence of the o.h.c.

Sir,
I wonder if you would care to publish some facts and figures on mass produced engine manufacture, in reply to Mr. Hindmarsh last month ? It is certainly true that an o.h.c. layout is more expensive than push-rods if we compare a Vauxhall Viva with a Hillman Imp-type arrangement (I choose the Viva since it’s probably the least expensive, to manufacture, whilst being very sound engineering). The increase in cost comes from having to make removable bearing caps for the camshaft, cast and machine an extra piece (the tappet block), use larger tappets with adjusting shims, a longer timing case with chain tensioner and a chain about twice the normal length. This more than offsets not having push-rods, rockers and pedestals; in addition, another source of oil pump and distributor drive has to be provided. If, however, we make the comparison with the Opel Rekord type of o.h.c., there probably isn’t much difference since the cost of separate skew gear for the oil pump and distributor, larger pressed steel timing case and belt tensioners is offset by cheap sintered pulleys and belt, no tappets or tappet bores and no push-rods. The rocker arrangement stays the same and provides as easy a method of servicing as the o.h.v, layout. The provides inertia of the rocker is in fact less than a bucket tappet and the system is probably the best and the cheapest. By way of comparison, the total reciprocating valve train weight of such a layout is at least 10% less than using a bucket tappet and about half that of a push-rod system.

The advantages of weight reduction are that either the spring load can be reduced to give much less wear, or the cam acceleration rates can be increased to give better power and torque whilst retaining tractability. The present power outputs of small car engines are very dependent on the latter and partly for that reason the industry is changing to o.h.c. since the wear rate with push-rods would be unacceptable. If anyone doubts that wear occurs in modern valve gear, let him strip out the cam, tappets and rocker shaft after 100 hours running from new; they will probably be thrown away in disgust and new parts fitted. Power unit assembly is certainly not a major cost, accounting for only about 1% of the total and is about the same cost as doubling the length of the timing chain. If expertly organised with sensible operators, results not much inferior to Rolls-Royce or racing mechanic practice can be achieved. The superiority of the latter lies in prior modification of the components rather than putting them together, which is skilled but simple fitting. For example, one manufacturer, at least, finds it considerably cheaper and quicker to feed special rally engine and gearbox components down the normal assembly line in about 25 minutes rather than spend days doing it individually by hand. And provided all the power tools are in correct adjustment the result is virtually identical. With any luck they will accidentally, lose one into a production car one day, which should make running in quite exciting. I can just imagine it “I’m sorry madam but I can’t make it tick over under 1,700 r.p.m. You’ll have to put in a guarantee claim !”

Coventry. C.B. Mynott

The Ford Corsair V4 road test.

Sir,
As a reader who has returned to Motor Sport after a few years absence, I was interested to read your comparison of the Ford Corsair V4 1700 model and the Cortina GT. I bought one of the new V4 models immediately it was announced—incidentally I am still waiting to see another on the road.

The Ford replaced the second of two Riley 1.5s, which gave reliable, if not entirely comfortable, service for 85,000 miles between them. The later model (1963) did suffer from a host of minor rattles and ailments, including, in the first few months, the replacement of the battery and fuel pump. It also had a ravenous appetite for tyres, making even SP41s crack round the sidewalls.

The Ford was therefore purchased as a change from B.M.C. products. Most of your criticisms of the Ford are very fair, however one or two points spring to mind. On my car the clutch is so light that it takes some getting used to. Also your reported petrol consumption seems rather high. Although I have not made a careful check, my car seems to use no more petrol than the Riley, which, carefully checked, returned 30-32 m.p.g.

The steering of the V4 developed an ominous rattle after 1,500 miles. The official dealer reaction was that this was a “common Corsair fault” and they would put it right. This, plus the search for another steering rattle, a hunt for a gremlin in the back seat and an unsuccessful investigation into the appearance of the generator warning light at normal motoring speeds, means that my car has already been off the road for four days of its young life.

Incidentally, this provided me with the experience of driving an ordinary Cortina 1200, generously lent by the Ford main dealer. This car certainly had a much heavier clutch and less positive steering than the Corsair.

I now hope to experience some of the reputed Ford reliability, although there are still the products of three more of the “Big Five” to try.

Lowdham. J. Bryan Dixon

John Cobb’s Napier Engines

Sir,
I have read with considerable interest your article on John Cobb’s land speed record attempts, noting the emphasis you place on certain facts quoted in italics. As a further tribute to the efforts of those engaged, I would seek to put on record that Napiers were approached to afford test bed facilities to enable engine tuning and power checks to be made. These unfortunately could not be carried out due to the fact that suitable beds were non-existent. The marine version of these engines, the unsupercharged and less powerful “Sea-Lion,” required an inclined bed to simulate the attitude of the engine in the boat to suit its power line angle and these beds were fully engaged to meet an impending war. For this latter reason alone the manufacture of a new bed was out of the question. The point I am making is that these supercharged engines were presumably tuned in the chassis for the 1939 record attempt, and apparently very successfully—a truly formidable task.

A further point of interest is that these engines were groundboosted for air record purposes, whereas Bonneville Flats are at approximately 3,000 ft. altitude and a certain power loss therefore resulted. Under the aegis of A.J. Penn, the interesting task befell the writer to help in calculating the optimum supercharger gear ratio for maximum power at the record run altitude. This resulted on paper in a gam of 130 h.p. New gears were made and we had the gratification of later experiencing Cobb’s creation of a new record. Alas! his glory was diminished by the almost immediate outbreak of war. For this quiet, modest and unassuming man of notable purpose and achievement, his end was indeed tragic.
To misquote Wordsworth (with apologies to Milton) :—
“Cobb ! thou should’st be living at this hour.
England hath need of thee,
She is a fen of stagnant water, etc., etc.”

Weybridge. I.I. Ellis.