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).
Analysis of flywheel designs and a comparative study of various American car engines.
| Identifier | ExFiles\Box 173\4\ img061 | |
| Date | 4th December 1935 | |
| -3- These were removed by torsional flexibility in the flywheel. No crank damper is fitted at the front end. The production engines with an ordinary flywheel and no damper are rough, but the engine with the conic flywheel is the smoothest I have ever tried and had no periods either full throttle or running up the engine light up to 5,000 r.p.m. The crankshaft has 3 bearings of 2 1/4" dia. the rear 1.15/16 long, intermediate 1.3/16 and the front 1.11/16. The pins are 2 1/4" dia. and the rods 1 1/4" wide, side by side, with .005" total end float. If we are going to make a V-8 engine I suggest buying one of these engines and trying it in the Vulture or a 20/25. The flexible flywheel allows high compression ratios (about 6.5) without any pick-up roughness. Some interesting figures. All at 3800 r.p.m. Engine Stroke C/R.{Sir Henry Royce} Comp.Pressure Type Buick 40 3 7/8 5.8 115 o.h.v. La{L. A. Archer} Salle 4 1/2 6.25 155 side valve V-12 4 6.0 135 o.h.v. Chevrolet 4 5.6 126 o.h.v. Pontiac. 3 7/8 6.2 148 side valve All the o.h.v. engines had an approximate volumetric efficiency of 80 at low speeds and 68 high speeds, and the side valve engines 77 low speeds and 62 high speeds. The G.M. side valve engines have a new silent tappet fed by main oil pressure that is said to be reliable. I have a sample of this and arrangements for supplying air free oil. The G.M. oil cooling is not circulating the oil in the cylinder block as one of their people told me, but continuing the water jacket to the very bottom of the cylinder skirt and on the V engines down the crankcase as well. | ||