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).
Valve timing, considering excessive overlap, cam specifications, and tappet clearance.
| Identifier | ExFiles\Box 13\3\ 03-page390 | |
| Date | 3rd March 1932 guessed | |
| -2- This week I heard of a South American living near here sending his Graham-Paige (recently new) for sale because it was doing under 8 miles per gallon. In the past RR. cars have been exceptionally good for their HP., and we must not expect to be free from criticism - some of it right, but much all wrong. VALVE TIMING. We must be alive to the fact that excessive overlap may spoil slow running. If this is not so valve timing is settling down to. - changeover - i.e. E.C. & I.O. 2 equal cams, exhaust lengths of 225º with this clearance (probably our 240º with .013 clearance.) 112º apart. The only doubt is how much overlap. .020 tappet clearance. R.{Sir Henry Royce} | ||