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).
Modifications required for an inverted tooth chain drive for the camshaft.
| Identifier | ExFiles\Box 124\1\ scan0031 | |
| Date | 8th March 1939 | |
| BY/NS.{Norman Scott} c. Rm.{William Robotham - Chief Engineer} c. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} DA.{Bernard Day - Chassis Design}3/G.8.3.39. 1044 B.60 INVERTED TOOTH CHAIN DRIVE FOR CAMSHAFT. Please received herewith :- E.CD.534 Chain Driven Camshaft Sprockets - Bentley 60. A new camshaft is necessary owing to the rotation being reverse to a gear driven shaft. This means that the relationship of inlet and exhaust cams is reversed, the opening and closing sides of cams are reversed and also the spiral gear for oil pump drive is altered from R.H. to L.H. The only thrust on the camshaft will be from the oil pump driving gear in a forward direction, acting against the plunger spring at the front end of camshaft. The crankshaft and the wheelcase are unaltered, except for a chamfer in wheelcase nose to give improved clearance with chain. The camwheel is now fixed to camshaft with setscrews in place of studs to facilitate removal of cam wheel. Please note the additional holes in the cam wheel and also various relationship of features to facilitate the valve timing operation. The lubrication of the chain is via the plunger in the cam wheel, an extra radial hole being shown in the front camshaft bearing and two radial holes in the spring plunger. The oil feed pipe and nozzle used with the gear driven camshaft drive for lubrication of the timing gears will not be required and the hole for nozzle in the wheelcase should be fitted with a screwed plug. The driven gear of the oil pump drive is reversed to maintain the correct rotation of pump and distribution, the thrust on the oil pump drive also is reversed and now opposes the thrust of the oil pump spiral gears. The chain to be used is an inverted tooth type silent chain of 48 links, .500" pitch and 1.000" wide. For convenience in the experimental stage, a | ||