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 causes of tappet noises in the Phantom engine and tests on different push rod materials to reduce expansion.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan025 | |
| Date | 1st April 1926 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to E.J. RS.{Sir Henry Royce's Secretary} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to EY. Wor.{Arthur Wormald - General Works Manager} ORIGINAL HS{Lord Ernest Hives - Chair}5/LG22.4.26. PHANTOM TAPPET NOISES. X8060 X3801 One of the worst difficulties on the production Phantom is to produce engines with quiet tappets. There are numbers of small points which can cause noisy tappets. One of the most important ones is the fact that the tappet clearance increases, from cold to a normal temperature, from .006" to .007". On the Silver Ghost at normal temperature the tappet clearance was .002" to .003". On the New PhantomCodename for PHANTOM I it is .009" to .010". We have tested push rods on the test engine for expansion under running conditions. The materials used were as follows :- 1. Standard steel rods. 2. Corronil metal. 3. Brass. 4. Drawn phosphor bronze (BZ/PD). 5. Gunmetal (BZ/G). 6. Cast phosphor bronze (BZ/PC). All these rods were solid with the exception of the first (standard). The extreme conditions of temperature taken were :- (a) Engine cold. (b) Water at 80°C - oil at 80°C. The following results were obtained :- contd :- | ||