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).
Faults with camshaft and valve timing and proposing an inspection to establish standard limits.
| Identifier | ExFiles\Box 33\4\ Scan070 | |
| Date | 24th August 1921 | |
| BY.{R.W. Bailey - Chief Engineer} from EP.{G. Eric Platford - Chief Quality Engineer} c. to Sft.{Mr Swift} c. to Hs.{Lord Ernest Hives - Chair} X1770 EP{G. Eric Platford - Chief Quality Engineer}9/H24.8.21. X.3423 RE CAMSHAFTS, VALVE MECHANISM & CORRECT X.1770 VALVE TIMING. X.2764 We have from time to time returned to the Works Camshafts which have given incorrect valve timing, such as to cause distinct faulty working of the engine. There also seems to be considerable variation in the timing of the engines and I am anxious to fix some limits in this direction. In taking a retrospect of the engines which have some through test, it would appear that the "timing" had the following faults:- 1. The exhaust valve is open slightly too long by about 1° or 2° (.004" tappet clearance). 2. That the angle between the exhaust and the inlet is slightly more than it should be by about 3° or 4°. 3. That the inlet does not open quite long enough. I shall be glad if you will arrange for the features which control the action of the valve to be inspected. Apart from the camshaft, the fault may be also due to the rocker arms, tappets etc. I shall also be glad to know to exactly what limits the opening and closing of the valve can be specified. At present these vary considerably, but as long as the engine is satisfactory as regards its power and efficiency, we have not tied ourselves down to small a limit. It is a fact, however, that this variation is being brought to our attention by depots and by owners of cars, and we should like to fix up a definite limit as standard for this job. EP.{G. Eric Platford - Chief Quality Engineer} R R C° LTD Derby (No 1) H Nov 1920-C 1000 | ||