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).
Troubleshooting tappet clatter issues related to oil temperature and system aeration.
| Identifier | ExFiles\Box 17\6\ Scan155 | |
| Date | 14th September 1933 | |
| -2- Hn{F. C. Honeyman - Retail orders}/Swdl.{Len H. Swindell}5/KT.14.9.33. the tappet clatters for a period of 1 - 2 minutes, this period appearing to be dependent upon the oil temperature, that is, the higher the oil temperature the longer the period of clatter before commencing to operate. When cold it functions almost immediately. The difficulty appears to be in getting rid of the air out of the system and it is noticeable how much more aerated the oil becomes when hot. We have tried to overcome this by drilling a .015" hole in the top of the plunger housing as an air release, but this makes the cushioning so soft that the tappet never becomes silent. Light return springs on the ball valve have been tried in order to make sure the ball kept on its seat, without any success. We are having a plunger made in bronze which should when hot take up a cold clearance .0005 - .00075 to almost a dead fit and so compensate for the thinning of the oil. The inability of the mechanism to take up quiet immediately upon starting when the engine is hot is identical with the failing we had on the original silent tappets tried out on the Phantom to Lec. 2908. Hn{F. C. Honeyman - Retail orders}/Swdl.{Len H. Swindell} | ||