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 component performance and issues, including pistons, bearings, and carburetters.
| Identifier | ExFiles\Box 101\2\ scan0044 | |
| Date | 20th July 1936 guessed | |
| ( 4 ) PISTONS. LOP E.60781 LMC 4744. Complete to above LOP & scheme incorporating:- E.60632 Piston - Die Cast. [Handwritten Note] Mths.{Reg Matthews} Should be investigated before proceeding with running. Rm.{William Robotham - Chief Engineer} No piston knocks were heard during 13,000 miles running, an occasional knock then developed. The compressions were uneven at the end of the mileage & Nos. 4 & 6 cylinders were very poor. The pistons and cylinders have not yet been examined as further running has been in progress. The average of the daily oil consumption was 580 m.p.g. for the first 1,000 miles, 860 m.p.g. for the next 1,000 miles. It then varied between 800 and 1,100 m.p.g. according to the driving conditions. There was no subsequent fall in consumption that could not be accounted for by leaks. At no time have we been troubled with oily ignition plugs. BEARINGS. LOP E.60757. Complete to above LOP incorporating:- Main Bearings in W/MT. Intermediate Bearings grooved Ex.19004/5. CONNECTING RODS. LOP E.60840 Complete to above LOP incorporating:- EB.2815/6 Connecting Rods & Caps. Big end Bearings in Hall's Solid Metal. There has been no falling off in oil pressure or undue rise in oil temperature, which indicates that the bearings are in good condition, so we have not disturbed them. With normal driving, the oil temperature is approximately equal to the water temperature, but it rises progressively to 100°c with increased speed and hot weather. A maximum of 110°c can be obtained under extreme conditions. With the oil at 80°c, the pressure is 30 lbs/Sq." at 70 MPH. and 12 lbs/Sq." at 10 MPH. CARBURETTERS. LMC 4883. Stromberg Carburetter EX. C.16 unit. New Stromberg Carburetter to Standard Production, fitted at 17,354 miles. Carburation is good for acceleration and power, but we have been troubled with periodic leanness on pick-up since fitting the new carburetter, the cause of which has not yet been found. No trouble was experienced from petrol boiling in the float chamber, and starting was easy at all times. The engine is rather irregular while idling and this could not be improved by means of the slow running adjustments. The choke butterfly valve stuck due to the carburetter body becoming oval. This can only have been caused by the pressure of the clamp fixing the pipe from the air silencer. | ||