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 findings regarding engine piston rattles following tests.
| Identifier | ExFiles\Box 35\2\ scan 227 | |
| Date | 14th April 1920 | |
| x.2748 RE PISTON RATTLES. Bnl/W13. 4. 20. Copy to Bn.{W.O. Bentley / Mr Barrington} x.2448 x.345/a C. to Ey. C. to EP.{G. Eric Platford - Chief Quality Engineer} c. to EFC. c. to EFCS The action to be taken in connection with Piston Rattles was further considered at a Meeting between Hs.{Lord Ernest Hives - Chair} EP.{G. Eric Platford - Chief Quality Engineer} and Bn.{W.O. Bentley / Mr Barrington} on Monday afternoon, April 12th. The information on this subject reported by the Experimental Dept. now stands as follows:- (1) Piston Rattles have occurred on three standard engines (one being on the Test Bench and two on the road) in all cases using Castrol as Engine Lubricant. (2) Piston Rattles have occurred on 7-CA with standard Lubricant but with fine clearances on the top band of the piston. (3) Rattles appear to occur with standard pistons but using Castrol after five to six thousand miles on the road and disappear when the engine is decarbonised. (4) Standard pistons using our standard lubricant (Price's) in most cases show similar but less pronounced markings on the top band to these markings found on pistons which rattle but no cases of piston rattle have occurred. (5) Modified pistons having an extra ring at the top of the piston have been run successfully on Castrol Oil for about 2,800 miles and for 50 hours on the Bench. These pistons show signs of picking up on the narrow top band but it is not thought that any harm could result from this. (6) No modified pistons with the ring at the top have yet been run on standard lubricating oil. From the facts brought forward it is confirmed that no action should at present be taken to modify pistons which have been manufactured, built into engines, tested, or delivered. ( Contd.) RECEIVED E.P.C. APR 14 1920 | ||