The Engine - an introduction

Much of HP6161’s engine components are based on standard 12/50 items. However, the Alvis machine shop worked on virtually every element to extract maximum power in what was a very competitve class of engine size at the time. The crankshaft was lightened, as were the conrods, and high compression pistons fitted along with a much modified head. In the lower geared 200 miles cars this gave Harvey a vehicle that would exceed 100 m.p.h.; whilst in HP6161’s case Alvis produced a car that was, to quote “capable of at least equalling the world’s standing kilo(meter) 1½ litre record one way”*

* Percy Joseland, Alvis Service Manager, quoted in a letter to his nephew Mark in March 1968. He goes on to say that “It usually ran big ends on the first run and I believe never did two runs, one each way, within the time limit.”

The engine was fitted with dry sump lubrication to eliminate oil surge (the double scavenger pump is seen, above right, fitted to the bottom of the sump). This is not normally a problem in Sprint cars and serves to reinforce the belief that, in part, No.1 was a test bed for the radical ideas that were being fed into the Brooklands Racers. The increased capacity of oil (just under 3½ gallons), held separately from the engine, does serve to keep oil temperature down which is also a significant factor in long distance racing.

(left) The underside of the crankcase showing the lightened Phoenix crank and rods, fitted in 2003 to replace the damaged originals. The removal of excess metal from the crankcase webs was another 1923 weight-saving factory modification.