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).
Technical specifications for engine components including valves, manifolds, carburation, and ignition.
| Identifier | ExFiles\Box 21\6\ Scan087 | |
| Date | 27th October 1933 | |
| -6- Hm{Capt. W. Hallam - Head Repairs}/14d.S/KT. 27.10.33. (e) Valves. It is a side valve engine. Silchrome valves are used with 45° seats. Valve head diameter, inlet 1.5", exhaust 1.375". Valve stem diameter .3415" - .34275". Valve stem length 5.08". Valve lift .34375". Tappet clearance (hot), inlet .006", exhaust .008". (f) Induction and Exhaust Manifolds. The attached photographs and sketches show the arrangement of the exhaust and induction manifolds. The induction manifold is very generously heated both by a large hot spot on the manifold, and also in the head where the ports are in close proximity to the exhaust ports. A hot spot control is provided which has two positions, winter and summer. The control valve in the winter position deflects the exhaust gases from the rear four cylinders through the hot spot. The valve is in one piece with a cap in the exhaust manifold, and is retained by a clamp. To alter the valve position the clamp is released and the cap rotated through 90°. (g) Carburation. A downdraught Carter carburetter is used and is bolted on to the exhaust manifold; the induction port passes right through the exhaust manifold. There is no mixture control; starting is effected by means of a butterfly type of choke valve; an accelerating pump is fitted. It is a 1.25" bore carburetter. A Monro air silencer is fitted, details of which are appended. (h) Ignition. Battery ignition is used, the makers being the Electric Auto-Lite Co. Twin contact breakers are used. An automatic governor is incorporated in the distribution drive which gives a range of 22°. There is no manual ignition control. The ignition is timed on T.D.C. in the retarded position. Firing order, 1, 6, 2, 5, 8, 3, 7, 4. In common with most American cars the electrical system is 6 volts. | ||