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).
Overheating issues and potential causes on Chassis 56-WR following the fitting of new cylinders.
| Identifier | ExFiles\Box 47\2\ Scan150 | |
| Date | 31th October 1929 | |
| Sèvres X4117. P/"Hm{Capt. W. Hallam - Head Repairs}" copy to "Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}" " " "D/Bf" " " "D/L" " " "WH" Ps3/RJ.3I/IO/29. Re: Chassis 56-WR - H.Mills Esq. Further to my Ps3/RJ.24/IO/29, the cylinders specially sent from Works have been fitted to this car with satisfactory results. Taking delivery, the owner drove the car at high speeds accompanied by our Mr. Allen, to Dijon, a distance of about 400 kms. from Paris, and on arrival, did some stiff mountain climbing. He has since returned, and expresses complete satisfaction with both the absence of overheating and the car's good general performance. Mr. Allen reports that Mr. Mills drives the car all out, no matter what the conditions are prevailing. This then confirms the theory that the overheating is caused by loss of water due to the water being forced to the top tank of the radiator, in excess of the radiator's capacity to take it. From the experience gained with these complaints, I have formed the opinion that apart from the known fact of cylinder head corrosion and its effect of stopping up the radiator, the question of the water pumps' output at high engine revs. being in excess of the flow capacity of the radiator, might be considered. The bottom outlet pipe appears to be on the small side, and the bend is very acute. It might be argued that the output of the water pump can only be equal to the intake. Quite true, but the pump is capable of sucking the water away from the bottom tank and lower part of the radiator, which is not entirely made up, owing to insufficient flow capacity. Therefore, it is possible a large part of the matrix is water starved at high engine revs., and this produces two EVILS:- a) Reduction in the amount of water exposed to the cooling surfaces, and b) Reduces the amount of water in the water system, brought about by piling up and draining away via ......... | ||