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).
Specification sheet detailing the design of reciprocating parts and valve gear.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan34 | |
| Date | 28th January 1926 guessed | |
| contd :- -2- RECIPROCATING PARTS. I section split big-end connecting rods, have gudgeon pins floating in aluminium pistons, the latter having three rings (one, a scraper in the skirt) and a slightly domed head. The big ends are split diametrally to permit of mounting on the crankshaft and of fitting the roller cages. A sketch of one of these roller cages is given on the accompanying sheet. (sketch 1.) The half-cage as shewn has seven rollers, each 15 mm. long X 7 mm. diameter with a brass retaining cap riveted to the main body of the cage. VALVE GEAR. Two overhead camshafts run in roller bearings and are driven by spur gearing from the rear end of the engine, next to the flywheel. They operate the valves through light finger followers, pivoted on the camshaft casing, against the resistance of triple valve springs. These springs exert a resistance of approximately 155 lbs. when the valve is open. The spring collars are of exceedingly light construction being grooved for the springs and drilled liberally to reduce the weight of the metal. They are held on the valve stems by split taper locking pieces. Adjustment of spacing is obtained by fitting thin steel packing discs under the thimbles on the valve stems. Spacings (or clearances) given :- Inlet 0.012" Exhaust 0.015". The valve timing found most suitable for supercharging (taken on 1925 G.P. model) :- contd :- | ||