Rolls-Royce Archives
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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).
Proposal for a radiator bypass system to improve engine warm-up times and prevent piston knock during city driving.

Identifier  Morton\M3.7\  img008
Date  22th July 1919
  
SOUND CONCISE ARGUMENT FOR COOLANT BY PASS IN LONDON WITH ALUM PISTONS - HS{Lord Ernest Hives - Chair} IN GOOD FORM. 4

To R.{Sir Henry Royce} from EH
c. to CJ.
c. to BN.{W.O. Bentley / Mr Barrington}
c. to L.
c. to DA.{Bernard Day - Chassis Design}

ORIGINAL.

EH3/LG22.7.19.
22nd. July 1919.

X.2631
X.3456
X.3563
X.3499

RE - MEANS OF CONTROLLING WATER TEMPERATURE.

We noticed when driving 49-GB in London that when running the car as one would anticipate it to be run when used for shopping, that although we had the radiator shut off by means of a blind, we still could not keep the engine warm. This was due to the fact that in traffic you run with very little power and before you have time to heat up the large quantity of water (7 galls.) the car is stopped for another interval. We think under these conditions that the bye-pass scheme for the radiator would be much more effective because you would not have to heat up the whole of the water; the water in the radiator would remain at a very much lower temperature than the water in the engine. The effect of this would be that the water would arrive at the normal temperature very much quicker.

If the water temperature is low, the tendency for the aluminium pistons to knock is very much greater and we think it is more important than ever that when the car is pottering about in London, that it should be free from knocks.

EH.

R.R. 235 A (100 D) (S.P. 575) 16-4-19. CL. 2354.
  
  


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