Details of an Ambitious Austin Seven Special r-iC
The builder of which, now a Captain in the Royal Engineers, prefers to remain anonymous,—Ed. THE Special with which I Used to amuse myself before the war is one amongst many Austin Seven specials, but it was unlike most in a number of ways. Details of some Of the More unusual alterations carried out may be of interest to MOTOR SPORT readers who are contemplating similar specials for
use after the war. Incidentally, it has occurred to me that the ideal place for a spot of 750-c.c. racing would be the perimeter: track of one of the many airfields now springing up all over the country. It would be wonderful and inexpensive sport for the impecunious enthusiast. Perhaps other readers have similar ideas ? The only snag I can see is the high accident rate likely on a track of this description !
This article is written entirely from memory after four years of war, in which most of my time is spent keeping pace with the inventions of the hated Humand I hope I will be forgiven if some of the technical details are a trifle vague or inaccurate—’ haven’t seen the car for three years.
Originally it started life as a 1928 baker’s delivery van, with a long and honourable career behind it delivering pork-pies. Consequently, I bought it very cheaply, although the engine was still in good shape. We stripped the body off and dismantled the whole of the chassis, cleaning everything and rebushing where necessary.
It was decided that the Austin Seven -wheelbase was too short and that the existing transverse springing did not lend itself to lowering. In any case the A iistin standard front-end can never be made to steer or hold the road really well. So old Morris-Cowley chassis members were welded to the sides of the Austin frame.
A G.N. was found in a field near home and the Owner gave me the complete issue, being only too pleased to see the last of it. We dismantled this one morning and loaded all the bits that mattered into the back of my sister’s Morris Twelve, much to her annoyance, as some of them were rather dirty. The chassis frame we tied to the roof, thus conveying one complete G.N. (less engine and body) home in one day. Incidentally, it was quite untowable. The engine was beyond all hope, and was not an interesting type, so it was left hidden in a ditch.
The G.N. 1 -elliptic springs were attached to the Morris side members. The G.N. stubs were discarded and Austin Seven stubs welded into the G.N. axle, thus making the track about 6 in. wider than standard. The whole assembly was rather floppy, so two radius arms were inade up from channel steel and bolted to the stubs and frame on each side. These looked very professional, as they were thoroughly drilled. The Austin steering was discarded and an old type Talbot ” 10/23 ” steering assembly was procured complete from a breaker. The reduction box is carried on a bracket bolted to the new side members. The steering column is almost horizontal, and the large steering wheel set extremely comfortably, although there is very little room to get in and out of the car. The front brakes, of Bowden
type, were taken from a crashed M.G. ” Magna,” as the old Austin cable system seldom compensated, owing: to the wider
track and lengthened wheelbase. It always chose the most awkward corners to lock, with startling consequences. The effect of these alterations to the front-end was to shift the weight of the
engine about 12 in. back from the front axle. This improved the road-holding and steering immensely. The radiator is about 6 in. behind the front axle and has greatly improved the general appearance of the car. The back-axle was lowered by flattening the springs. The rear brakes are standard Austin, the whole system being operated either by foot or by means of a horizontal lever about 2 ft. long outside the car. This latter gives immense leverage and is invaluable. The wheels, being 1928, had light spokes, and they soon collapsed when the urge was applied, so post-1930 wheels were fitted later. Motor-cycletype tyres are used, studded at the rear and ribbed at. the front. The engine was stripped down and completely overhauled. New main bearings were fitted, the two-bearing crank being retained as I couldn’t procure an ” Ulster ” engine cheaply enough. The big-ends were re-metalled and the block
bored out 20 thou. Incidentally, the people who did it told me it was one of the hardest they had ever bored. Oversize ” Extralloy ” pistons were fitted, a highlift overlap camshaft was obtained from Laystall’s, and Terry ” Aero ” valvesprings were used. New valves NV ere ground in to the existing sea tings, which were in good condition. The usual port polishing Was carried out. The Austin inlet manifold was retained and two Zenith downdraught carburetters bolted on to it.
Exactly how much was taken off the head I forget, but it was more than 116 in. Using a Klingerit gasket the compression ratio is around 8 to 1. I didn’t think an alumininin head was worth the expense, as they don’t improve performance very much and they invariably warp. Champion 113 or If 1 plugs are used. The magneto is a special 11.T.H. wound for high r.p.m. The flywheel was turned down on a lathe until it was only about 4 in. thick. This proved disastrous, as the clutch springs proved too strong. Fortunately the crankcase stood the shock and my feet remained intact. It made the most expensive noise I have ever heard. and I thought the old two-bearing crank had given up the ghost at last. However, a new flywheel was fitted, again about A in. thick, except at the centre and outside of course. The first one broke where the flywheel is drilled and threaded for the withdrawal bolts. This may be of interest to other special builders, who have lightened Austin flywheels, and I think it is probably quite an uncommon
form of breakdown in the ordinary way.
In addition to the foregoing improvements the whole engine was assembled with great care and a lot of time spent on minor alterations and adjust uients. Originally the 3-speed gearbox was retained, operated by a remote change
consisting of a large hinge and a cut-down G.N. gear-lever linked by a rod to the stub of the Austin gear-lever. This sometimes helped me into reverse when hurrying to change from 1st to 2nd. however, never worried, as 3-speed boxes are cheap. Later, a 4-speed box replaced this arrangernent, with a proper remote change.
An almost straight-through outside copper exhaust system from an 11.14l. was fitted. Unfortunately I had no rev.-counter, but I think the engine in its final form probably got somewhere near the 6,300 r.p.m. mark. Fuel was the chief problem owing to the high compression ratio, but
Cleveland Discol used to be satisfactory. The best fuel was 33/ per cent. ethylbenzole-petrol. If I was using the car
on the road I usually replaced the Klingerit with a standard gasket. Castro! ” R ” was used throughout. The body was knocked up from multiply board, lath and fabric. The long bonnet ran from a standard Austin radiator (which I intended to replace) to a fabric scuttle flaired up to the steering wheel. The Sides were cut away and the whole of the rear was taken up by a large petrol tank from the crashed M.G. ” Magna.” Two bucket seats, also from the ” Magna,” just fitted. Easily detachable motor-cycle-type wings are used, front and rear. The whole car is very low and really looks quite workmanlike. Petrol is pumped from the rear tank by
pressure-fred, the pump being from an A ustro-Daiinler :; in addition, there is a G.N. tank under the scuttle. Final performance was fully up to C 1 1eCt ations. Acceleration and road
holding, for which it was designed, were both excellent. No figures are available, but 50 m.p.h. in 2nd, using the 3-speed box, was quite common. We ran in several speed trials and hill-climbs with a certain amount of success, but there is seldom a special class for unblown 750s, so ” firsts were few.
Most pleasure was had on the road ; we could beat most ;11.(;.s and the like from the start up to about (10 m.p.h., usually to their annoyance. On long high-speed runs pre-ignition sometimes occurred, but I think it could have been cured by using :1 larger radiator, an alterst ion I had started on just before the War.
Needless to say the first time I ever took the car out a policeman spotted it and stopped me. He expected a rich haul. I have no doubt, but having checked such elementary things as licence, insurance. etc., and found all in order, he started peering around. The driving mirror and horn were both there, but eventually he spotted the rear number plate, which was not quite the correct size I Nevertheless, I hope to have my special on the road after the war is won.