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).
Cylinder and piston lubrication, particularly the risks during cold starts and comparing different engine models.
| Identifier | ExFiles\Box 14\3\ Scan030 | |
| Date | 29th January 1929 | |
| Hs{Lord Ernest Hives - Chair} ✔ C-By ✔ C-Wor{Arthur Wormald - General Works Manager} C-MP from Mx.{John H Maddocks - Chief Proving Officer} Mx{John H Maddocks - Chief Proving Officer}3/T29.1.29 CYLINDER & PISTON LUBRICATION With reference to your Hs{Lord Ernest Hives - Chair}1/LC25.1.29. We are very interested in this matter, as we certainly do not agree that any recent modifications have accentuated the risks of insufficient lubrication when starting up. The early Silver Ghost Cars were doubly protected, as it was the invariable practice when starting up to depress the extra oil valve and so directly lubricate the pistons - furthermore the carburation did not allow the engine to be put under load until it was thoroughly warmed up. On our present production the exhaust heating of the carburetter permits the engine being put under load almost immediately. Lubrication of cylinders is perforce kept to a minimum to prevent overoiling, smoking, etc. We find it takes approximately 10 minutes light running after starting up before oil reaches the cylinders and pistons - this time depends very much on the air temperature. During cold weather we have to be particularly careful when starting up. We submit that positive lubrication of pistons when starting an engine from cold should receive consideration, as quite apart from the risk of seizure,(which we agree is a diminishing one in the life of the car, as lubrication tends to increase with running) we do feel that the wear of pistons and cylinders during the warming up period must be considerable, and as we know we can only avoid knocks by working to very close dimensions with the cylinders and pistons, and that an increase in clearance of .0002 will make a piston knock occur, it would seem that positive lubrication would permit of a little more latitude, and give a greater life to the engine. Mx{John H Maddocks - Chief Proving Officer} [Signature] | ||