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).
Issues and improvements related to petrol consumption, cylinder bore wear, and bearing failures in engines.
| Identifier | ExFiles\Box 144\2\ scan0080 | |
| Date | 15th June 1941 | |
| -3- Cont'd.{John DeLooze - Company Secretary} crown wheel and pinion on Limousine 8-cylinder cars if we are to have sufficient margin of safety on production. This means a new design to adapt these pieces to the semi-floating axle and, of course, upsets rationalization considerably. Petrol Consumption. The B.V's average about 2 M.P.G. worse petrol consumption than the B.II's. We have spent a lot of time trying to establish the cause of this difference, and have succeeded in regaining the lost economy by reverting, as far as possible, to the B.II induction system. Briefly, we have made small differences in the carburetters, air silencers and induction pipes all of which had an adverse effect on fuel economy. We regard these tests as very important, because any small car we make must have good fuel economy. Cylinder Bore Wear. As we have previously pointed out, now that we have increased the size of all the engine bearings and, in the high power head, have valves that will run 50,000 miles without a regrind or tappet adjustment, cylinder bore wear has become the limiting factor in determining when an engine overhaul is necessary. We have, therefore, been running various experiments with liners in cylinders and also chromium plated bores. The chromium is cheapest, costing perhaps sixpence per bore, and should about double the period between re-bores. Short liners in high chromium iron are more expensive, perhaps five shillings per bore, but they are likely to increase the life of the cylinder as much as four times and we shall probably recommend them for our top priced models. Some of these are fitted to the engine of 30.G.VII, which, in spite of bus works stopping and starting, shows no signs of requiring attention at 70,000 miles. Bearing Failures. We have had two mysterious big end failures, both on customers' cars, to which new bearings had been fitted. -Continued- | ||