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).
Specification document for a Straight '8' Engine, detailing construction, cylinder head, and porting.
| Identifier | ExFiles\Box 6\6\ 06-page002 | |
| Date | 7th May 1934 guessed | |
| SPECIFICATION OF R.R. STRAIGHT '8' ENGINE. bore 3" x stroke 4.5". Capacity- 4.17 litres or 254.5 cubic inches. Con rod over stroke ratio = 1.925. Engine construction. alum cylinder block integral with crankcase with detachable alum head of so called J.J. design and as used on spectreCodename for Phantom III. Cast iron cylinder liners preferably of high expansion alloy sealed with double rubber glands to crankcase. We propose also to build up an engine of cast iron throughout from the same patterns to test for relative smoothness of operation. Cylinder Head. Of the compact turbulent type with vertical valves as used on Bentley, but with two ignition plugs opposed across the head. Double synchronised ignition should improve thermo dynamics of engine. Cylinder head secured to block on the principle of 5 studs per cylinder crown but total number of studs does not exceed 29. [Handwritten above diagram] Push Rods [Diagram of a straight-8 cylinder head with labels 'FRONT' and 'REAR'] [Handwritten note] Valve sizes with inserts All exhaust and inlet gas ways taken out on non push rod side of head to allow for full exhaust heating of induction with thermostatic control. Inlet ports of 1 and 2, 3 and 4, 5 and 6, 7 and 8 siamesed on Terraplane 8. Design also allows for head casting to be altered to eight separate inlet ports. Exhaust ports 2 and 3, 4 and 5, 6 and 7 siamesed, and 1 and 8 single. We should | ||