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).
Specifications for a piston and associated rings, including dimensions and clearances.
| Identifier | ExFiles\Box 126\4\ scan0005 | |
| Date | 26th April 1910 guessed | |
| Eccentric rings 7 to 8 lbs. to close Piston 4-7/8" diameter 4-1/4" long hollow top. 2" top of piston to gudgeon pin hole Four rings 7/32" wide clearance as per sketch | ||