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 a Vauxhall '25' engine, detailing specifications and valve gear data.
| Identifier | ExFiles\Box 127\4\ scan0062 | |
| Date | 9th August 1937 guessed | |
| 1097 Vauxhall "25". Model. Vauxhall "25". Bore. 3.226" Capacity 3.215 c.c. Stroke. 4.000". Compression ratio. 6.1 : 1 Performance 80 B.H.P. at 3,600 r.p.m. Valve gear data. (1) Inlet valve. (a) Tappet clearance = .006" at working temperature. (b) Valve. As per sketch (Fig. 1) Conditions of seats reasonable, but the general M/C finish of the valve head was rather poor. (c) Ports. See Fig. 2 The general finish was very poor only the seat being machined. This was very broad as shown. There was no guide boss. A general port arrangement is shown on Fig. III. The ports in general seemed a square section, Nos. 1 & 2, 3 & 4, and 5 & 6 being siamised. (2) Exhaust valve. (a) Tappet clearance = .013 at working temperature. (b) Valve. As shown in Fig. IV. the seat condition was very poor being completely scaled up and pitted on both valve and head. M/C finish not too good. (c) Port. As per Fig. V.{VIENNA} There were four exhaust ports. Nos. (1) and (6) cylinders being single and Nos. (2 & 3), and (4 & 5) siamised. | ||