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).
Valve troubles in post-war cars and a proposed scheme for lubricating valve guides.
| Identifier | ExFiles\Box 74\3\ scan0322 | |
| Date | 9th June 1922 | |
| [Header text, top left: R.{Sir Henry Royce} 326A (100 T) (S.H. 798, 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2947] [Stamp: RECEIVED JUN] [Initials, left side: Mr., E.W.H., H.I., HS.{Lord Ernest Hives - Chair}, RB.{R. Bowen}] X4432 Hm{Capt. W. Hallam - Head Repairs}/NRC{N. R. Chandler}3/W9.6.22. Valve Troubles on Post-war Cars. X4432 With reference to Mr. Hives' report - Hs{Lord Ernest Hives - Chair}4/T1.6.22, we can confirm that the wear on the valve guides and stems of post-war cars has become a very serious matter, and it is no uncommon thing for it to be necessary to fit oversize valves, and ream out the valve guides after 6,000 miles, in order to get decent slow running, and to cure exhaust blows. We have made some experiments with a scheme for lubricating the valve guides. Herewith is print R.1203 showing the arrangement of the scheme. It will be noted that the oil supply is taken from the cylinder extra oil supply, and that the quantity is restricted by felt discs. We propose that the valves and guides should be made both undersize and oversize from a given standard, so that both valves could be ground down till they reach the minimum, and bushes reamed out till they reach the maximum, so that if the valve bushes are reamed out for larger valves, the old valves can be ground down for another car, but if new undersize bushes are fitted the existing valves can be ground down, so that either new valves or bushes can be fitted according to requirements while either the valves or the bushes can be used in another car until they reach their minimum and maximum size respectively. Experiments with this scheme are not yet completed, but so far as they have gone it appears quite possible to keep the guides oily without excessive leakage down the stems. The felt pads at the bottom of the guides show no signs of becoming charred after an hour at full load on the dynamometer. With regard to cost, we have not yet been able to obtain definite figures, owing to the "Lock-out", but we are of the opinion that if each valve can be ground down two or three times, and each bush reamed out two or three times, that the cost will be less than supplying and fitting new valves only, especially as the valves and guides are likely to last much longer than when unlubricated. Contd. | ||