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).
Letter discussing clogged oil passages in gudgeon pin bushes and potential causes of heavy carbon deposits.
| Identifier | ExFiles\Box 103\2\ scan0166 | |
| Date | 14th March 1928 | |
| Ma. Derby. C. to Mr. London. (crossed out) Hs.{Lord Ernest Hives - Chair} Derby. H.A. (crossed out) X5030 Pt.4/FH-14-3-28. In reply to your Ha.1/EW-21-10-27, I beg to advise you that I have had despatched to Captain Hallam at Derby one 20 H.P. connecting rod ex chassis GSK10 andfour gudgeon pin bushes ex chassis 6RB.{R. Bowen} In the lubricating pipe of the connecting rod and the anuli of the gudgeon pin bushes will be found a heavy deposit which effectually clogs and hinders the passage of oil to the gudgeon pin bushes. I regret to say that any analysis you may have made of this deposit may result in very deceptive conclusions because all these parts have been immersed in a bath of 25% phenyle in order to cleanse them and make working upon same an easier job for the fitters. In consequence any analysis will probably show a very large percentage of moisture and creosote with a possible small percentage of iron oxide due to the fact that engine cylinders are also immersed in these baths. I would expect silica to be found indicating road dust contamination of oil in sump but I am at a loss to understand the presence of what is obviously carbon in very large quantities. I cannot conceive of any conditions in the normal running of our cars which should result in this heavy deposit of carbon provided the recommended oils are used. In the case of 6RB{R. Bowen} there is no doubt that the car has been running for probably 40,000 miles or so in a somewhat neglected condition, but so far as GSK10 is concerned I can vouch for the fact that its owner is one of the fussiest we have, changing his oil completely every 750 miles and insisting upon using Price's Motoring B oil. This car was delivered in January 1926, decarbonised in November 1926 and again decarbonised in May 1927 and the total mileage to date is 17,000. No car could be more carefully used and yet, as you will see, the oil pipe on the connecting rod is blocked up. I feel sure you will agree with me that this is serious and I shall be glad to have in due course your conclusions. Pt. | ||