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, the need for a choker or pilot jet, and subsequent engine wear.
| Identifier | ExFiles\Box 50\3\ Scan072 | |
| Date | 2nd May 1921 guessed | |
| (2) The heated induction pipe has not improved this feature at all except that after starting the engine it is possible to reduce the richness of the mixture as soon as the exhaust pipe gets hot. What we urgently need before next winter is a choker or pilot jet scheme of some sort. We are putting the experimental choker scheme on 4EX for Mr.Hives to see, but will have very little time to try it out before the car must leave. While it is still possible to seriously spoil the lubrication of the engine with the choker, it is not nearly so easy to do so as it is with the priming device, because with the choker, due to the high vacuum in the induction pipe, sufficient of the gasoline evaporates to give a firing mixture so that the engine will start quickly in cold weather, whereas with the priming device, it is often necessary to work for 15 or 20 minutes on an engine before it can be got to run with consequent damage to the lubrication of the engine. We know that Mr.Hives is working on this scheme, but are writing this in order to point out how necessary it is to improve the ease of starting. Naturally, we desire to fit this improvement to the cars as soon as possible, as otherwise we shall have a great deal of trouble next winter. Complaints received from customers last winter were serious, but there were only about thirty-postwar cars running whereas the coming winter there will be 200, and unless something can be done to cure the trouble very soon, we shall be placed in a very serious position when the cold weather starts again. We are instructing that particular attention shall be paid to wear of cylinders so that we can obtain an idea of the proportion of damage occurring to engines from this cause during winter running. Yours truly, Rolls-Royce of America, Inc. Per.......................... MO/G CCMr.Belnap Mr.Beaver Mr.Nadin Mr.Bagnall Mr.Hulley Mr.Southern Mr.Manning. | ||