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).
Report comparing the performance and cost of Mercury, Champion, and Bethlehem spark plugs.
| Identifier | ExFiles\Box 50\2\ Scan026 | |
| Date | 9th February 1921 | |
| R.R-W-555- (108 T) (R.R.H.728. 19.12.20) O.{Mr Oldham} 2247 Contd. -3- HS{Lord Ernest Hives - Chair}5/LG9.2.21. From the results of these tests we place the - Mercury plug the first Champion U.S.A. plug the second and the Bethlehem U.S.A. plug the third. All of these plugs have pot type insulators and they are all detachable. Although the insulators on the Bethlehem plugs failed on the bench test, we think this should be looked upon as an exceptional condition. Under road test conditions we had no trouble with these plugs. We know from experience that nearly all of our troubles on the present plugs are due to over-oiling or sooting up. We must be prepared that a plug which will give excellent service in the car may not stand up on the bench test or dynamometer test. The Mercury plug is made in Birmingham. It is of simple construction using French porcelain as an insulation. The plug is completely detachable and it is an easy matter to fit a new insulator. The price is approximately 1/6 each compared with 2/1 for the Lodge. We recommend that we order 500 of these plugs for a start so that we can be certain the quality will be maintained. Champion Plugs. R-R Service Depot at N.Y. have used hundreds of these plugs on R-R cars and they claim excellent results. They are using Champion Plugs on R-R cars built at Springfield. The price they pay for these plugs is 10 cents each (5d). Hs.{Lord Ernest Hives - Chair} | ||