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 clearance issues caused by settled cylinder gaskets, and the recommended practice for reusing them.
| Identifier | WestWitteringFiles\T\2July1928-December1928\ Scan134 | |
| Date | 10th October 1928 | |
| HS.{Lord Ernest Hives - Chair} FROM E.{Mr Elliott - Chief Engineer} ORIGINAL. VALVE CLEARANCES AND CYLINDER GASKETS. X615 X8060 Y5060 X5050 We recently noticed that 12-G-4. had developed defective slow running, and on examining the valve clearances found that there was no clearance in any of the inlet valves, and that some of the exhausts had inadequate clearance. Some of the inlet valves were not seating at all. Our conclusion is that the cylinder gasket had settled down since the engine had been re-assembled recently at Derby, and since any vertical movement of the head is multiplied about two and a half times at the valve end of the rockers the clearance is soon lost. A new gasket settles down quite a lot as a rule but one that has been used is in a solid compressed state and does not give rise to this trouble. We understand it is general practice in the trade to use a new gasket every time a cylinder head is lifted, but we think this is only necessary on a poorly designed cylinder where there is a tendency to leak, or where the use of sticky dope has torn the gasket apart. On a correctly designed cylinder we believe the gasket can be used over and over again, thereby avoiding much trouble with valve clearances after an engine has been assembled. This is particularly so if the gasket is liberally coated with graphite grease before use each time, which avoids any sticking when the head is again lifted. R.{Sir Henry Royce} has asked me to send you these few notes embodying our experience with cylinder head joints. E.{Mr Elliott - Chief Engineer} | ||