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).
Letter providing advice on components and fluids, including the cylinder head, fuel, sparking plugs, and oil.
| Identifier | ExFiles\Box 89\3\ scan0020 | |
| Date | 24th August 1936 | |
| -2- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}17/KW.24.8.36. (6) The head is not aluminium, but cast-iron. (7) I believe they are proposing to supply you with a standard head for your car in addition to the high compression head. I believe the cost figure for this is about £25, but Conduit Street will confirm this with you. (8) You do not use any gasket when you fit the plate, the reason being that the plate is fitted under the block; i.e., between the block and the crankcase, and so does not have to withstand any gas pressure. (9) Controllable shock absorbers. I do not honestly think that it is worth while fitting these. It is a big job. The primary function of the controllable shock absorbers is to allow a man to load his Saloon Bentley up with passengers and luggage and then correct for this overloading by increasing the shock absorber loading. For a light open touring car the advantage gained is insignificant. (10) Fuel. We should prefer you to use Aviation spirit rather than a mixture with a very high percentage of Benzol, because pure Benzol is likely to have an undesirable effect upon petrol pump diaphragms. However, a 50% Benzol mixture is quite a good spirit. (11) Sparking Plugs. You have two choices, those we have given you with the high compression head and those fitted to your standard head. For ordinary touring conditions as opposed to racing, the standard plug should be O.K. in the high compression head. However, you will be able to try these out for yourself while you have the car in Scotland. (12) Oil. I am finding out the S.A.E. rating for you. The main objection I have to running thin oil in hot weather is that it makes the engine very noisy. It also may foul up the spark plugs if it gets by the pistons. I should say that S.A.E. 30 or 40 are about right for Summer work, and will let you know what the S.A.E. number of Mobiloil Arctic is when I get it. The commercial name for Ethylene Glycol in America is Prestone. We should prefer you to use Prestone to pure Glycerine. | ||