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).
Engine modifications including coolant jets, a new cylinder head material, and general inspection results.
| Identifier | ExFiles\Box 97\3\ scan0142 | |
| Date | 15th June 1939 | |
| -4- COOLANT JETS. Coolant jets have been fitted to this unit in accordance with the scheme ECD.1349, four directing water to the exhaust seats from the exhaust side and three from the inlet side. The object of the above is to overcome cracking through the exhaust seats as experienced on the previous 30,000 miles test on S.B.V. Checking the temperature in the cylinder head, the exhaust side ranges from 82°C - 85°C and the inlet side from 78°C to 80°C. Tests on the valve temperature and detonations indicate no practical change from standard conditions. However, we anticipate that if the theorising of water-ways as affecting sinkage and cracking of seats is responsible, then this scheme should show up satisfactorily after a long mileage. Coupled with the coolant jet scheme is the new material cylinder head Nickel-Chrome-Molybdenum. GENERAL. A slight leak occurred past the rear main bearing after continued high speed running, due presumably to blow-by creating crankcase pressure, which from previous experience, anticipate will be cured when the extractor breather pipe is in operation on the road. The inlet valves are fitted with the alum oil sealing washers and are satisfactory. INSPECTION. Prior to being fitted in the chassis, the unit was stripped down and everything appeared in excellent condition, including the 3-layer Vandervell main bearings, the Vandervell little end bushes with drip feed and the Monichrome camshaft running direct in the crankcase. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||