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).
Engine lubrication, oil flow, and the effectiveness of 'L' section piston rings.
| Identifier | Morton\M18\ img085 | |
| Date | 26th June 1925 guessed | |
| cont'd :- -5- This engine has been tested at full load 27 H.P. on the bench and ran perfectly well without any sign of excess oil to pistons. When shut down it was guided by hand and examination of the cylinder bores showed over-lubrication without excess. This seems proof that oil flow as low as [illegible] is quite sufficient and reliable for successful operation of the engine. PISTON RINGS. We have demonstrated that rings exert an influence upon over-oiling the worst offenders being those which, on the ring i.e. possess up and down movement, in the grooves as they tend to have a pumping action on the oil. 'L' section rings are excellent when new but even in an engine having excessive oil flow will usually correct over-oiling only unfortunately their high efficiency rapidly decreases as would be expected, with wear. When their efficiency reaches a minimum constant value they should still be equal to plain rings or even superior to new plain rings because they would have 'lapped' themselves to the cylinder bores. Therefore from consideration of the above there is no reason why 'L' section rings should not be employed. There are various other factors exerting slight, but unappreciable, influence on oil consumption, such as piston - see previous reports. It should be mentioned in passing that we have met with no success by employing various forms of oil baffles, numerous types have been tested but not a single one has lowered the over- cont'd :- | ||