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).
Page two of a letter from Alex Taub to W.A. Robotham discussing spark plug gap and positioning.
| Identifier | ExFiles\Box 127\4\ scan0178 | |
| Date | 20th February 1940 | |
| 2. W.A. Robotham, Esq., 20th February, 1940. position relative to the geography of the chamber and the walls near the points. I remember a few years ago being asked by Janeway why the Plymouth spark plug would not respond to any change in gap above .024. I found his plug over the intake valve and in this area the "medicinal" effect of the wide gap is not needed, since this is a rich area. They could not put the plug on this head over the exhaust valve because it resulted in poor starting. So you see, if your plug is in an ideal position and conditions do not require correction, you will not make a gain. For instance, if you scavenged extremely well and made an M.P.G. gain thereby, you would not make a cumulative gain by adding extremely wide gaps. Wide gaps on our job are not as effective on the dynamometer without exhaust silencer as they are with silencer. Do I bore you? Well I'll shut up and hope to see you soon. Yours sincerely, Alex Taub. | ||