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).
Laboratory report analyzing a deposit sample from a Bentley Rear Axle lubricated with Mobiloil 'EP'.
| Identifier | ExFiles\Box 145\1\ scan0079 | |
| Date | 9th January 1934 guessed | |
| COPY. HL1/AG.1.1.34. Laboratory Report No. L2911. Re: Sample of Deposit from Bentley Rear Axle after running 14000 miles, lubricated with Mobiloil "EP{G. Eric Platford - Chief Quality Engineer}". The analysis of the deposit submitted is as follows:- Oily matter - 81% (by weight of whole deposit.) Loss on ignition of residue obtained after extracting oily matter as above - 15.15% " Iron (estimated as oxide) - 1.25% " Copper (estimated as oxide) - 0.9% " Sulphur. - 1.7% " We are of the opinion that the cause of the accumulation of this type of deposit is the high sulphur content of the oil, i.e. 1.4%. This reacts readily with copper alloy parts, present in the axle casing, resulting in the formation of copper sulphide which is black and has the appearance of carbon deposit. We have connected together three materials present in the casing, viz. S/ZN, R.R.50, and Phosphor Bronze and have immersed them in Mobiloil "EP{G. Eric Platford - Chief Quality Engineer}" for 24 hours. The oil was agitated and maintained at a temperature of 50 - 55°C., as being an average working temperature of the part in question. It will be seen that the Phosphor Bronze and the copper wire used for binding the pieces together have developed quite a heavy coating similar to that complained of. In service this coating probably reaches a thickness great enough to cause it to detach and become mixed with steel wear product etc. thus forming quite a voluminous mass, leaving clean surface ready for further attach. HL. | ||