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 reliability and wear of a self-adjusting valve mechanism after road tests.
| Identifier | ExFiles\Box 17\6\ Scan173 | |
| Date | 31th January 1934 | |
| -2- Hs{Lord Ernest Hives - Chair}/Std.10/KW.31.1.34. to be held just off their seats (due to the difference between hot and cold clearances - this only amounts to approximately .002"). However, on running for approximately 3 to 4 minutes all the valves were found to be seating correctly. These eleven rods were then fitted to 37-EX car and run for about 40 miles successfully. However, after another 80 miles one of them (No. 10 valve) developed a considerable clearance, resulting in serious noise. Various others also showed signs of holding the valves off their seats - hence rods were removed from engine. SUMMARY It appears that while this method of self-adjustment can be made to work, it is not reliable, and probably calls for a high degree of accuracy in manufacture (in the case of the square threads). Also, it would appear that even a tappet of this type which was working successfully would become unreliable when wear took place. Hs{Lord Ernest Hives - Chair}/C.E.Stedman. | ||