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).
Investigation into the causes of and solutions for noisy tappets on Phantom and 20 HP cars.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 24 | |
| Date | 1st April 1927 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to BJ. Wor.{Arthur Wormald - General Works Manager} ✓ c. to RG.{Mr Rowledge} ✓ E.{Mr Elliott - Chief Engineer} c to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} ✓ C to OY. ✓ R Schemes ORIGINAL Hs{Lord Ernest Hives - Chair}2/LGS.4.27. PHANTOM AND 20 HP. TAPPETS. XS060 √S060 Noisy tappets are a trouble with us on Phantom and 20 HP. cars. On the last quarters returns of customers complaints, approximately 50 Phantoms had been attended to at the Depots for noisy tappets. A considerable amount of time is spent on the production test in order to obtain quiet tappets. Investigations on both production and experimental cars confirm there are two chief causes of noise :- (1) The flick caused just as the valve is closed. Noise actually comes from the valve on its seat. We consider it is due to the side thrust caused by the rocker. We have been able to make a very noticeable improvement in reducing this complaint if we arrange a rocker so that there is no side thrust at the point where the valve closes. This modification has been tried out on several production and experimental cars and from the results we are certain thatit will enable us to obtain quieter tappets and save a considerable amount of time. We have run a Phantom engine fitted with this valve gear for 100 hrs. on the test bench; we cannot measure any wear either on the valve guides, valve ends or rocker. (2) The rotational movement of the tappet in its guide. We have now got the solid key type tappets as standard; these are an improvement. We also find however it is a definite advantage to increase the amount of contd :- | ||