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 to Cadillac seeking information on induction pipe silencing, shock absorbers, and exhaust valve practices.
| Identifier | ExFiles\Box 170\2\ img111 | |
| Date | 31th October 1931 | |
| Ha/Ba.3/KT. 31st October 1931. M.Olley, Esq., Cadillac Motor Car Co., Detroit, Michigan, U.S.A. Dear Oy., Can you give me any information on how to silence induction pipe roar. I understand that Cadillacs' have done a lot of work on this subject and have met with some success. We ourselves are, of course, quite familiar with what is possible with valve timing and carburetter arrangement, but should like to know whether it is possible to cure roar by using a cast iron induction pipe and large air intake silencer. One other point in which we are interested, is the little Delco which is fitted to the Plymouth and latest Chrysler Six. These are so small we presume that they are single acting. We should like to know, however, whether Delcos' are producing a small double acting shock absorber for cars about the Plymouth size which do not require such high damping loads. With regard to exhaust valves burning, can you tell us the latest practice with regard to inserted seats in cast iron heads. Also if on the exhaust cam, American practice is to reduce the toe or duration of gradual opening of the valve lift, which is usually employed to obtain silence. In many cases the exhaust valve appears to be only .012" off its seat after forty or fifty crankshaft degrees from its initial lifting point. This appears to us to be fatal from a burning point of view. With kind regards and hoping business is picking up in the States, Yours sincerely, | ||