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).
Engine issues including piston fit, oil consumption, suspension, and weak carburetion.
| Identifier | ExFiles\Box 71\4\ scan0069 | |
| Date | 19th March 1925 guessed | |
| - 2 - pistons, because the valve rockers are getting very much less oil than previously, hence there is much less flow of oil down the valve stems. Also, the pistons that we fitted were certainly no better fit than the old ones, they were fitted up for a standard size bore, the cylinder bores on this engine are all oversize, I think the rear block are S plus a half, and the front block S plus one. We will refit the relief valve again to find out whether this increases the oil consumption again. We have been watching the new front engine suspension since we fitted it. We had suspected that it was giving way in the same manner as the old one. On examination to-day, we can definitely state that the engine has dropped at the front end. As regards carburation being weak on the pick-up, we do not think this is due to there not being sufficient heat to the hot-spot. Having had constant trouble with the exhaust choke sticking open, we can say that 90% of the running has been done with this stuck open. We found this weakening off very pronounced after having cleaned the air valve; to ascertain whether the weakening off was due to wear on the piston of the air valve, (which was found to be quite sloppy), we then smeared the inside of the air valve with oil to have the effect of a good fitting piston. We found that the tendency to weaken off was eliminated, the carburation being normal again. A.J. LIDSEY. | ||