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).
Adjustments to a piston assembly and spring tensions for a magneto relay.
| Identifier | WestWitteringFiles\Q\December1926-January1927\ 36 | |
| Date | 9th December 1926 guessed | |
| contd :- -2- COLLAR Normally, if the inner piston is set flush with the top of the large piston, 6º initial advance is obtained. As this is more than is required, we have arranged a small collar in the neck of the inner piston. This stands .060 above the face of the top of the piston and when set level with the outer piston head, gives the correct 2 - 3º initial advance. The 6 - 9 lbs. return spring over the relay is hardly strong enough to cope with the metal piston rings, especially when the oil is cold. The effect on the road is detonation after luffing up, and suddendly opening out. The controls have to be very easy to make the system work with the 6 lbs. spring and we are particularly anxious to avoid slack when these are fitted up initally. The Lucas magneto, fitted on 12-EX, has less friction than the Watford. Considering everything, we should like to make this spring as nearly as possible 9 - 12 lbs. Experiments shew that the relay can deal with this with 10 - 15 lbs. oil pressure; A 2 - 4 lbs. spring being fitted to the magneto. Hs{Lord Ernest Hives - Chair}/W.A.Robotham. | ||