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 a loud clatter from a Peregrine engine, identified as piston noise.
| Identifier | ExFiles\Box 2\1\ B002_136 137-page04 | |
| Date | 26th August 1932 | |
| Files. X136. 26.8.32. PISTON NOISE - PEREGRINE. When motoring the Peregrine engine over at 4900 RPM.(58 MPH in 3rd gear) on the chassis dynamometer it was noticed that a loud clatter emanated from the engine. The noise began quite suddenly at this speed and increased in magnitude with increase in speed. It was shown by successively removing the balance weights, push rods, cylinder head, and cam pinion without altering the noise that it is not due to the master torsional period, valve bounce or a critical speed of the valve gear. With the pistons and rods absent the noise had vanished. It was then noticed that the big ends had been moving sideways to the full limit of this clearance (.040) the white metal being scored. Tests were then carried out with the clearance increased to .050 and with no clearance at all without affecting the clatter. A further test with tight fitting pistons with no split in the skirt is being prepared. Hm{Capt. W. Hallam - Head Repairs}/Grylls. | ||