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).
Remedies for over-oiling engines, focusing on piston designs and lubrication modifications for the Phantom engine.
| Identifier | ExFiles\Box 72\1\ scan0117 | |
| Date | 15th December 1925 | |
| R.R. 498A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -6- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/ACL/LG151225 a badly overoiling engine has been effected by the use of 'L' section rings. The unfort-unate part is that the efficiency falls rapidly with wear, and as we know, the piston rings are not operating under conditions which tend to promote long life. (3) Pistons. We have not been able to obtain any substantial reduction in consumption of a badly over-oiling engine by means of different piston designs. It has been found however that if the overoiling tendency is not too great, we have been able to reduce the consumption slightly by employing a piston which fitted the bore tightly at the bottom of the skirt. This probably with regard to 'life' would be similar to the 'L' section rings. In any event it is not desirable to employ tight fitting pistons. Drilled pistons also shewed a slight improvement. It can be said generally, however, that the efficiency of the latter two factors i.e. - piston rings and pistons - depend in the first place upon the amount of oil passing through the bearings and therefore make this factor of primary importance. Therefore from careful consideration of these points we recommend that the Silver Ghost practice of feeding the 3 main bearings only and allowing indirect feed to the intermediates via the crankshaft should be applied to the Phantom as we are of the opinion that apart from the advantages we may possibly gain, we possess no advantage by employing 7 direct feeds. We are at present time engaged in fitting up a Phantom with such modifications and hope before long to have figures for bench tests and road tests of this engine. Hs{Lord Ernest Hives - Chair}/A.{Mr Adams} C. Lovesey. | ||