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).
Specifications for engine components including the crankshaft, pistons, and connecting rods.
| Identifier | ExFiles\Box 21\6\ Scan086 | |
| Date | 27th October 1933 | |
| -3- HB{C. E. Harcombe}/14d.3/KT.27.10.33. The A.C. petrol pump is operated in the usual way by a cam integral with the camshaft. The remaining accessories, viz: water pump, dynamo and fan, are all driven by the fan belt from off the front end of the crankshaft. The water pump is mounted on the front end of the cylinder head and an extension of the rotor spindle carries the belt pulley and fan blades. Adjustment of the driving belt is provided by rocking the dynamo in its cradle. (c) Crankshaft. This is carried in five bearings; it has eight balance weights integral with the shaft. The crankshaft is solid and is a very rough job. The crankpins are bored out a little way from either side apparently for balancing. The attached drawing gives all the more important dimensions. (d) Pistons and Connecting Rods. It was not possible to get one of these out without entirely dismantling the engine. The following particulars are obtained from the "Major Specification of 1933 Cars" published in the American "Motor". The pistons are made of Lynite Aluminium and have 'T' slotted skirts; weight 9.25 ozs, length 3.1875". Clearances, top .016", bottom .0065". There are four piston rings, the bottom ring groove being drilled radially. Ring groove depth .150". The two compression rings are .09375" wide with .009" gap. The two remaining rings are .125" and .1875" wide both with .009" gap. A floating gudgeon pin is used .750" dia., 2.4375" long. A diamond cored finish is given to the hole and .0003" clearance allowed. The connecting rods are 6.1875" long and weigh 29 ozs. The big end bearings are spun Babbitt 1.6875" dia, 1.375" long. .001" clearance is allowed with .006" end play. | ||