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).
The investigation of an engine clatter on chassis 53-WR, traced to slackness in two connecting rods.
| Identifier | ExFiles\Box 66a\2\ scan0103 | |
| Date | 28th June 1929 | |
| x8060 SEVRES Ps to Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} Ps5/MLB.28.6.29 re: Chassis- 53-WR Hs{Lord Ernest Hives - Chair}/RMI.LG.26.6.29 This chassis came in from Nice whence we first heard of the valve gear vibration. Under test one would be led to think the trouble was somewhere there, the rattle can be discribed as running an engine with so many valve springs broken, on in other words a valve/gear clatter at a certain engine speed. In reality, we could not trace anything to this part and dismantled the timing gear case to find the camshaft with excessive play .008". Reducing this and changing the oil pump which was also noisy & worn (The car has only run 4000 kms) had little effect if any. We then suspected connecting rod or piston trouble and eventually found two connecting rods with a fair amount of slackness in the top and bottom bushes, reducing this cured the job. I have since almost brutalized the car in third gear to reproduce the noise, without results. Although I am pleased the trouble has been overcome, it seems remarkable to me that so little slack (.002 in the big ends and no signs of seizure) would cause such a clatter. When there must be many cars turned out, even new, (but not RR.) equally defective. Perhaps the secret lies in the fact that whereas two were very free, the other were a good fit to the crankshaft and pistons. Ps. | ||