From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Camshaft experiments for 20 HP engine power development.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 111 | |
| Date | 23th May 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. to BJ. Wor.{Arthur Wormald - General Works Manager}✓ c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer}✓ c. to OY. ORIGINAL Hs{Lord Ernest Hives - Chair}/ACL1/LG23.5.27. 20 HP. RR. POWER DEVELOPMENT : X5090 X5771 CAMSHAFT EXPERIMENTS. In a previous report was shewn how the power output of the 20 HP. engine had been increased by the following factors :- (1) Carburetters giving low induction pipe de-pression. (2) Larger valves. (3) Higher compression ratio. It was also explained that in order to obtain the maximum advantage from larger valves it was necessary to employ carburetters giving a low induction pipe depression. We have followed up these experiments by testing a camshaft which gave longer duration of opening to both inlet and exhaust valves in the endeavour to maintain a greater volumetric efficiency at the higher speeds. The experiments have proved to be very promising resulting in an increase in maximum power of 21% due to the camshaft alone. The peak of the power curve is now raised above 3000 r.p.m. and only a small decrease in power is manifest at the lower speeds, which is what we should expect with a long duration inlet cam. It is possible however that this may prove a definite advantage in allowing the use of a slightly higher compression ratio without increasing the tendency to detonate at low speeds. contd :- | ||