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).
Extract from a report discussing issues with spark plug positioning for cars destined for America.
| Identifier | ExFiles\Box 33\3\ Scan143 | |
| Date | 6th July 1921 | |
| X1812. le. Extract from EP{G. Eric Platford - Chief Quality Engineer}/Tnn6/H6.7.21. X.3719. RE CARS FOR AMERICA. Item 10. Position of Sparking Plugs. The following is an extract of a report from Mr. Platford on this matter:- "Am having great difficulty in getting the intermediate position plug used. The consistent good slow running obtained with pocket position plugs and Bosch Mag. is what they require most of all, and the use of pocket position of plug for battery ignition was being generally adopted. Much as they may tell the customers, they insist that customers will only use Mag. only (Battery only for starting u). With our present standard high compression and bad American gas - pinking under these conditions is hopeless and middle position plug must be used to make car run reasonably. Again slow run on mag. with high comp. 28.NE on middle plugs was good, but when compression lowered was bad. Hulley and Caswell say this is so and low compression engines are always bad slow run middle plugs compared with H.{Arthur M. Hanbury - Head Complaints} Compression. Can Derby confirm this? I think some proper experimental report should be made out on slow run, pinking and position on plugs so as to establish some facts and definite action. Will Hs.{Lord Ernest Hives - Chair} please go into the matter thoroughly, as he did with Mag. running and circulate information and get some standards P.T.O" | ||