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).
Outlining issues with a sample cast Bentley rocker cover and recommending further testing.
| Identifier | ExFiles\Box 88\4\ scan0085 | |
| Date | 25th July 1934 | |
| X254? To Sft.{Mr Swift} from E/Lid.{A. J. Lidsey} E/Lid.{A. J. Lidsey}5/HP.25.7.34. c. Mr. Hs.{Lord Ernest Hives - Chair} B---- Bentley Rocker Cover. - Sft.{Mr Swift}3/EJ.25.7.34. We have examined the sample rocker cover having the baffle cast on as a means of economy. We do not at the moment agree to this being instructed and suggest that the sample cover should be completely machined and submitted to the Experimental Department, for test. Our reasons for this are as follows:- (1) The overall outside dimension of the cast baffle is greater than the sheet metal baffle, and even when cast in its absolutely correct position leaves only .075" clearance from the valve springs. This we consider inadequate on a job of this kind. (2) If it is possible to reduce the outside dimensions, the inside dimension must be reduced accordingly, and the value of the breather may be seriously reduced because of its smaller volume. (3) The outside dimension of the baffle, as cast in the sample, may prevent the valve rocker cover being removed from the engine because we believe it is not possible to lift the Bentley rocker cover vertically off the cylinder head owing to the length of the rocker shaft. It is necessary to push the cover to one end of the head (as far as the clearance between the holding down studs and the cover will allow) lift one end of the rocker cover over the end of the rocker shaft and then release the other end of the cover. It is conceivable that the small clearance between the baffle and the valve springs will prevent this being done. (4) The baffle as cast in the head is provided with two internal baffles as against three in the sheet metal design. This may seriously influence the action of the breather as regards oil consumption and should not be adopted without testing. E/Lid.{A. J. Lidsey} | ||