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).
Cold weather starting issues for Bentley and 20/25 cars, recommending thinner winter oils and a geared starter motor.
| Identifier | ExFiles\Box 82\4\ scan0019 | |
| Date | 20th November 1934 | |
| To Hd.{Mr Hayward/Mr Huddy} (FOR DEPOT SHEET) c. to Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to Ey. The first 500 Bentleys that have been turned out and also the 20/25 are likely to give trouble with starting if they are not kept in a heated garage during the night. It is now universally appreciated that in order to get a car to start in cold weather it is necessary to use a thinner oil than that suitable for Summer use. This matter has been brought to our notice recently by Rn.{Mr Robinson} pointing out that 6 or 7 Bentley cars had to be serviced after standing out a number of hours in the cold because the owners could not start them. The recent test in America of course indicated that there the very thinnest oils had to be used. The matter has been taken in hand from a Design point of view, by the provision of a geared starter motor which greatly facilitates starting; in fact with this motor we can guarantee a start at zero. There will, however, be about 500 Bentleys out with the ungeared starter motor and this state of affairs also applies to the 20/25. We think information should be circulated to such people who have complained, to point out that by the use of a thinner oil car starting can be greatly facilitated. We have been in communication with the Manufacturers whose oils we recommend for the Bentley, and in each case they have a lighter grade which they put forward as suitable for winter use. The grades are as follows :- Wakefield's "CW". Single Shell. Mobilil "AF". Price's Motorine "M". In addition to a Depot Sheet we think that reference should be made to this subject in the Instruction Book, where it should be pointed out that in extreme climates oils such as SAE10W will have to be utilised. It should however be emphasized that if these thin oils are left in the crankcase during the Summer, considerable increase in oil consumption is almost bound to take place, which will result in increased carbon formation in the head. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||