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).
Exhaust valve stretch and sinkage for a 25/30 HP engine, including valve spring measurements.
| Identifier | ExFiles\Box 108\1\ scan0432 | |
| Date | 28th February 1938 | |
| Big E/C c/o Da{Bernard Day - Chassis Design} We have had the following note To. Rm.{William Robotham - Chief Engineer} from Waller MX.{John H Maddocks - Chief Proving Officer} c. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} re exhaust valve stretch 600a Rm{William Robotham - Chief Engineer}/10/MM 3/3/38 CHATEAUROUX 8/ .28.2.38. 26.G.VI.- 25/30 HP. VALVES. We have fitted the new exhaust valves, springs, and bottom tappets. We beg to confirm our telegram :- " 26G. SATISFIED LOST CLEARANCE DUE SINKAGE NOT STRETCH NOR BOUNCE" The valves removed were no longer when measured on a face plate, than the new ones. The seats showed definite signs of sinkage in direct relation to the amount of tappet clearance lost. The valve seats were not pitted and showed no signs of burning such as would be expected had they been bouncing. The length of the valve springs was measured before dismantling the valves and the exhausts again after fitting the new valves. 1: 1.512 2: 1.527, 1.496 3: 1.527, 1.496 4: 1.512 5: 1.434 6: 1.527, 1.496 7: 1.512, 1.480 8: 1.512 9: 1.512 10: 1.527, 1.496 11: 1.512, 1.496 12: 1.465 We are returning to-day the six exhaust valves removed for your inspection. Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} Ivan M.{Mr Moon / Mr Moore} Waller. | ||