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).
Anti-freeze mixture for 'M' Series Bentley cars.
| Identifier | ExFiles\Box 151\3\ scan0248 | |
| Date | 8th September 1938 | |
| 1285 To By. {R.W. Bailey - Chief Engineer} from Rm {William Robotham - Chief Engineer} /Std. c. LA. {L. A. Archer} c. W/LH. {Mr Haworth} - JLE. {J. Lee Evans - Chassis Test Manager} c. NW. {N. Walker - Patents} Rm {William Robotham - Chief Engineer} /Std.1/MH. {M. Huckerby} 8.9.38. 'M' SERIES BENTLEY - ANTI FREEZE. Referring to Rm {William Robotham - Chief Engineer} /Std.7/JH.2.9.38, LA. {L. A. Archer} O/T.6.9.38 and LE.10/D.C.9.38, we have discussed the matter with LA. {L. A. Archer} and By. {R.W. Bailey - Chief Engineer} and agree that anti freeze should be put in all 'M' series Bentley cars before they leave the Works, with a suitable label attached to radiator drain tap. In the case of chassis which have already left the works, retrospective action will be necessary, but we understand that this will present no difficulty. With regard to the amount of anti freeze - in order to minimise expense we are naturally anxious to put in the minimum quantity necessary of the most inexpensive mixture - the latter is Price's "Zero" which is practically pure glycerine. We have discussed this with By. {R.W. Bailey - Chief Engineer} and LA. {L. A. Archer} and have accordingly revised the recommendation contained in Rm {William Robotham - Chief Engineer} /Std.7/JH.2.9.38 and recommend that 20% mixture is employed, i.e. 1 part of "Zero" to 4 of water. The freezing point of this mixture is approx. 21°F (i.e. 11 degrees of frost) - at this temperature small crystals begin to form and the solution turns into a mush, which becomes thicker as the temperature falls, finally solidifying at approx. 6°F (or 26 degrees of frost). We recommend this proportion since the basic purpose of supplying anti freeze ex works is to prevent the bottom of the radiator being frozen up by driving the car away quickly from cold, and this percentage should prevent this down to an atmospheric temperature of about 16°F (16° of frost) since there is always a small circulation of water through the radiator from the thermostat bleed hole - this will raise the temperature of the bottom of the radiator a little above atmospheric temperature. Further, the formation of very small crystals in the bottom tank would not injure the car since it would still permit circulation, while the time in which they can form (between starting engine and attaining running temp. of 75-80°C, i.e. about 5 - 7 minutes) is small. We do not think we need cater for atmospheric temperatures below 16°F in this country - the instruction book recommendations will still hold if the car is used and left standing continuously in places where atmospheric temperatures below 21°F (11 degrees of frost) are usual. | ||