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).
Investigation into engine pinking caused by a fine powder deposit on spark plugs and a proposal to update cleaning instructions.
| Identifier | ExFiles\Box 33\3\ Scan256 | |
| Date | 22th September 1927 | |
| S/W. Hs.{Lord Ernest Hives - Chair} Copy to:- BP. By.{R.W. Bailey - Chief Engineer} H.{Arthur M. Hanbury - Head Complaints} X1812D. CWB14/GM/22-9-27. CLEANING OF SPARKING PLUGS. In a complaint case of pinking some few months ago, Frith of the Inspection Department, suggested that the cause might be dirtied plugs. In this case the plugs were removed, opened out and cleaned. There appeared to be very little dirt on them, but the whole of the surfaces exposed, when the plugs were taken apart, were covered with a fine dark brown dry powder. The effect of this cleaning was very noticeable and the degree of pinking was reduced to normal. The effect of thoroughly cleaning the plugs internally has been tried on two other cars subsequently, both of which had run very considerable mileages, during which, probably the plugs had never been taken apart, with a very material reduction in the pinking. In each case the interior surfaces of the plugs were coated with the same sort of dry powder. The evidence so far obtained, as described above, on this matter, does not appear to be sufficient to definitely state that pinking is caused by this dry deposit which seems to collect on all plugs after considerable mileage, but it does appear sufficiently important to follow the matter up and determine whether this is always the case, and also to stiffen up the instructions with regard to the cleaning of plugs in our Instruction Book, which at present only consist "Remove and clean the sparking plugs every 2,000 miles." Perhaps Hs.{Lord Ernest Hives - Chair} will endeavour to verify the facts of this matter and By.{R.W. Bailey - Chief Engineer} will consider the expansion of the instructions re cleaning sparking plugs so as to include taking them completely apart and making a thorough job of it say every 5,000 miles. CWB. | ||