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).
Sticking exhaust valves on Large Bore Bentley engines, proposing a modification to the valve guide dimensions.
| Identifier | ExFiles\Box 88\4\ scan0157 | |
| Date | 13th March 1936 | |
| To By.{R.W. Bailey - Chief Engineer} c. to E.{Mr Elliott - Chief Engineer} X254 Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}2/KW.13.3.36. Large Bore Bentley. The Test Dept. have reported several cases of exhaust valves sticking in the guides and the allowable clearance limit on the drawings shows that this can be from .0025" to .004". We have experienced similar occasional sticking when the clearance is on the low limit side. In order to minimise the risk of sticking, will you please alter the valve guide details (EB.1782) from .3437 + 1 dia. to .3442 + ½ dia. Including the valve dimensions, this will give an allowable clearance limit of .003 to .004". This should also apply to Ph.III. Hs{Lord Ernest Hives - Chair}/L.H.Swindall. | ||