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).
The Bensport engine, discussing increased compression ratios and solutions for camshaft over-running.
| Identifier | ExFiles\Box 3\4\ 04-page060 | |
| Date | 29th August 1932 | |
| X4653 E.{Mr Elliott - Chief Engineer} } FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} } R1/M21.S.32. Sent off 29.8.32. C. to SG.{Arthur F. Sidgreaves - MD} WCR. BY.{R.W. Bailey - Chief Engineer} re. BENSPORT ENGINE. I conclude from your conversation, and the evidence of Bugatti and others, that you expect to be able to work with an increased compression ratio of probably 5/1 to 6/1, if we have a type of combustion chamber and position of sparking plugs similar to our original 20HP. G.1., Alfa Romeo, and the latest Bugatti production, which means that we go on with our original programme for the Bensport engine. In consequence of the many difficulties attending the over-running of the camshafts due to the energy of the closing valves, or their springs, I have come to the conclusion that the only way of getting out of this trouble is to use a special compensator cam, probably one on each camshaft, or a compensating cam and a centrifugal brake, according to which we find simplest and most tractable. If then we prevented the camshaft from running away from its drive it does not matter what type of gear, or the amount of slack, or even a moderate amount of wear, occurs in the gear. We can also use a jaw coupling in such a way that we can lift the head and camshaft away without much difficulty. R.{Sir Henry Royce} | ||