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).
Findings for improving slow running, with recommendations on tappet clearances, ignition timing, and spark plugs, plus other issues.
| Identifier | ExFiles\Box 101\3\ scan0079 | |
| Date | 8th June 1937 | |
| -2- Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}5/AP.8.6.37 From our findings a much better standard of slow running can be obtained by the adoption of the following:- (1) Tappet clearances at .008 - .010 with hot engine. (2) Modified governor characteristic whereby idling ignition timing is later than at present. (3) K.L.G. FLB.30.X. spark plugs at .025". The new R.R. Wraith type coil is an improvement but has to do 15,000 miles before standardisation. Other small items which are worthy of some attention are as follows:- (1) Fraying of low tension ignition wires at the "Ross-Courtney" terminals, this being a flimsy job without support to the wire. (2) Appearance of nicely bodied cars spoiled by 6" of rusty tail pipe (exhaust). (3) Piston tops not machined, owners ask 'Have they forgotten to finish off my set of pistons.' (4) Rough internal surface of induction pipe and hot spot, and whether improved surface would effect improved running. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||