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 Lycoming Motors inquiring about achieving high exhaust valve lift and follower design for motor boat engines.
| Identifier | ExFiles\Box 174\2\ img220 | |
| Date | 6th December 1937 | |
| Rmll/R.{Sir Henry Royce} 6th December, 1937. Mr. Herrick, Chief Engineer, Lycoming Motors Ltd., WILLIAMSPORT. U.S.A. Dear Mr. Herrick, We have been experimenting with a high output engine having a side exhaust valve, and have come up against the difficulty of the exhaust valve lift. We find that where we get good volumetric efficiency on the inlet side, we require at least .375 lift on the exhaust side. This is on a 4 1/4-litre engine having a 3 1/4" bore. It is, of course, not easy to get more than .35 lift with the normal mushroom follower, as used in the States, also, there are various other types of follower such as that used by Hudson, Essex, or, alternatively, roller followers. We are wondering whether you have found it necessary to depart from the mushroom type of follower to get more exhaust valve lift on your motor boat engines which give such remarkable power output. Yours sincerely, | ||