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).
Answering questions on Buick oil coolers, General Motors crankcase ventilation, Hudson timing gears, and GM piston development.
| Identifier | ExFiles\Box 178\2\ img118 | |
| Date | 2nd January 1935 | |
| -10- Ha/Gry.{Shadwell Grylls}10/M.2.1.35. In answer to other questions :- (1) Buick have dropped their oil coolers, firstly because of expense, and secondly because considerable reduction in oil temperature was obtained when the cylinders were water-jacketed the whole way down. They did not consider the fact that coolers had to be cleaned every 20,000 miles should be a reason for abandoning them. (2) The General Motors organisation consider that through ventilation of the crankcase is an excellent feature for removing acid fumes, which they say can cause rapid wear of the timing chain and are also detrimental to lead bronze bearings. (3) We asked the Hudson people their view of Celoron timing gears. They were of the opinion that the spoked gear is no quieter than one with a solid web. They had also experienced several failures on test with the spoked arrangement. (4) We think we should take an interest in the G.M. piston development. They have a rig in which the crown and top land of the piston fit into a hard rubber steel-backed cup. Loads equal to the explosion loads are then applied at the gudgeon pin, and alterations are made in the design of the piston so that it stays circular under these conditions, to a maximum change in diameter at any place of .00025". From an examination of the drawings of our pistons, they anticipate a distortion of possibly .0015", with consequent liability to knocks and high oil consumption. | ||