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).
Engine development issues including overoiling, lubrication, oil filtration, and induction system improvements.
| Identifier | ExFiles\Box 6\6\ 06-page259 | |
| Date | 19th August 1937 | |
| -4- into trouble of overoiling when grummets become worn, as per Ph.III. It is impossible with the existing bushing of the rocker where there is an annulus right round, to regulate the flow as required, that is, only a 'weep' to the valve tip and a copious supply to the push rods, for lubrication of the bottom tappets. By adopting the Phantom III. solid bushed rocker (Leo. 5441) with slight modifications to the oil holes, ideal lubrication should be obtained. This system is at present running satisfactorily on the 15,000 miles Ph.III. 32-HX. In conjunction with the reduced ratio rockers, as previously mentioned to give a valve lift of .350, we have also instructed the bushing and lubrication in line with development on Ph.III. In order to cater for conditions of hot oil and idling, we may have to use constant leaks past the relief valve seats, in order to ensure the timing gears are lubricated under these conditions to prevent rattle. It has been decided to delete the Tecalemit type of external pressure oil filter and modify the crankcase accordingly. Although both 32-HX. and 26.G.VI. are running with a bye-pass filter which is a product of General Filters of Detroit, there is not enough data to say whether it is efficient. Against these American filters bye-pass filters made by the A.C. people are being tried. As described in our memo Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}7/AP.21.5.37 the bye-pass filter is preferable to the pressure type of filter. DISTRIBUTION. The distribution is not good and is biased by the air intake bend to one side. A system enabling the bend to be at right angles to the induction system is being made and should effect an improvement. Likewise for trial, the detail shape of the induction manifold is being made similar to that developed on the 20.H.P. unit. At low speeds the power is 'floppy' and a reduced bore induction system is being tried. In place of the single downdraught carburetter a Duplex downdraught Stromberg carburetter is being tried in conjunction with a separated manifold and using a small balance hole. From past experience some improvement should be effected in the low and middle speed M.E.P. by this system. | ||