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).
Notes on compression tests for different engine piston rings and cylinder configurations.
| Identifier | ExFiles\Box 19\7\ Scan005 | |
| Date | 24th April 1908 | |
| R.R. 148 (1g N) (M.C. 699. 16.3.08) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 3639. X790 4400 Compression test. taken with 6" dial gauges & non return valve. on M408 at R.A.C. best cylinder bore - 70 lbs. on road after stronger piston rings (hammered out) on 742 - ordinary rings, car on test. maximum of 60 lbs. all made the same on tower test engine with ground cylinders. Front 3 - weak rings. 61 lbs. Rear 3 - hammered taken - EP{G. Eric Platford - Chief Quality Engineer} 24/4/08 rings - 65 lbs. no perceptible difference if oil faced on cylinder walls | ||