THE AUSTIN-HEALEY CONVERSION
The “100” Becomes the “100M”
IN the latter part of the summer MOTOR SPORT found itself in need of a new staff car. It was to replace the Jewett Jupiter IA which was needed for another member of the staff. After some discussion it was decided to purchase an Austin-Healey, and the one that was eventually procured front a local garage was an ordinary 100 model in perfectly standard form. Running-in was less tiresome than many cars, as a fairly high road speed could be maintained with low revs. Maximum revs, for the first 1,000 miles were 2,500 r.p.m., which gave the following m.p.h. : first gear, 20 m.p.h.; second gear, 31§ m.p.h.; third and top gear, 45 m.p.h.; and with the overdrive 60 m.p.h. was top running-in speed. As most drivers know, a speed of 60 m.p.h. in this country is faster than that used by the majority of road users.
After 1,000 miles the revs, were gradually increased until at 2,000 miles it was possible to try using maximum power, which showed that 100 m.p.h. was possible on medimu-length stretches of road. Braking, however, from that speed felt slightly odd, as though the rear brakes were not working, but when the brakes were checked they were perfectly balanced. The local agents assured us that they were normal, which seemed to infer that Healey brakes were not much good. On one occasion when travelling at about 15 m.p.h. it became desirable to stop instantly, but this proved impossible, as the front wheels locked solid and the rear wheels hardly braked at all. The resulting bump had its compensations, as it resulted in replacing the inadequate headlamps with Lucas P700, making night driving considerably more pleasant.
On another occasion, at a speed approaching 100 m.p.h., the car grounded on a shocking section of the Southend Arterial road near Hornchurch, causing damage to the sump drain plug and the side’ screens to disintegrate. It was possible to go on using the car and a replacement sump was delivered in six weeks.
After 3,000 miles a clutch judder began to creep in, and developed during the next 2,000 miles until it shook the whole transmission on getting away from a standing start. The controllability at all speeds was good, and cruising speeds of 85 to 90 m.p.h. proved the most comfortable as long as one remembered the braking distance.
In the middle of October an advertisement Appeared for a conversion for the Austin-Henley 100 to a 100M, Or, as the advertisement stated, ” the Le Mans conversion.” It consisted of raising the compression-ratio from 7.5 to 1 to 8.1 to 1, high-lift camshaft, enlarged S. U. carburetters, steel-faced cylinder-head gasket, racing-type anti-roll bar and special setting of the shock-absorbers. Externally the car is resprayed in two colours and has a new louvered bonnet top held in place by a leather strap. The cost of these modifications is £105.
Having decided to have the conversion, arrangements were made for the car to go to the works, accompanied by a list of defects, most of them very minor ones. Heading this list was ” clutch judder and poor braking.” It took a fortnight to complete the job, and when the car was picked up the improvement was tremendous. First the dutch judder had gone, and the brakes now worked perfectly. Afterwards it was learnt that the front linings had been reduced in width by in., which made all the difference to fast driving. The handling at all speeds had improved tremendously— the car felt more balanced and stable on eerners, and with a new set of Michelin SDS tyres the improvement was even more
pronounced. Continued on page 69
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For ordinary open-road driving overdrive and top gear are all that are necessary with the extra 20 b.11.p. at one’s disposal. On stretches of road where 100 m.p.h. was reached previously. 110 m.p.h. comes up on the ” clock,” and over a well-known stretch of road the acceleration front a standing start to a certain lamp-post has improved from 50 m.p.h. to 59 m.p.h. On the petrol consumption checks that have been made since the conversion there seems to be no increase at all, as it is remaining between 21 and 22 m.p.g.
The car in its present form is a comfortable bigh-speed means of transport and as long as the driver doesn’t use the road as a race track, a sae meansof transport. On -long runs in this country, with normal traffic conditions, an average of over 50 m.p.h. can be maintained, weather permitting.