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).
Flywheel balancing methods and improvements to valves and valve seats, with reference to Chevrolet practices.
| Identifier | ExFiles\Box 126\4\ scan0123 | |
| Date | 2nd May 1936 | |
| -3- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}5/KW.2.5.36. (5) Grylls. Flywheel Periods. Whyman. In spite of elaborate dynamic balancing, etc., etc., Chevrolet's have finally come to the conclusion that the most satisfactory way of getting a smooth engine is to put weights on the flywheel when the car is on the assembly line. This certainly corresponds with what we have found to be essential, and we should inform production what we think is the most practicable method of doing this with all three of our cars. In the meantime Whyman should confirm that he can improve 36-EX by doing this. (6) Grylls. Valves & Valve Springs. Smith. Swindall. Taub says that they have improved the condition of their exhaust valve seats enormously by - (1) Going to a valve seat 3/32" wide in the cylinder head. (2) Ensuring that the exhaust valve never gets less tappet clearance than .003" to .005". (3) Has water brought well down the stem of the guide. (4) Runs .0025" to .0035" stem clearance. (5) Has water directed on to the seat by means of tubes pushed through, having holes directing water to the point required. Their standard camshaft practice is for the first .005" lift on the toe to have .0003" per degree, and the remaining .010", .0025" per degree, making a .015" toe altogether. In measuring the warming up increase in tappet clearances on the Chevrolet, Mr. Taub says that the centre cylinders generally increase more than the end cylinders; whereas the increase in clearances on the end cylinders is only .0045" to .005" on the centre cylinders this goes up to .007". We should check up if anything like this is happening on our engine. | ||