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).
Test report conclusion on Prima spark plugs, finding them inferior and not recommended for use.
| Identifier | ExFiles\Box 33\3\ Scan198 | |
| Date | 28th November 1921 guessed | |
| -2- The fibre sleeves fitted to the outside of the plugs also shrunk and became loose. Conclusion. We do not consider the Prima plugs have any advantages over such plugs as the K.L.G - Lodge etc.etc. in some points they are distinctly worse. We should not recommend for use on R.R. cars any plug in which the sparking gaps are not adjustable. We also should condemn the Prima plug from the method of holding the insulation. Before we recommend any plug, we run 3 sets of them on different cars for 10,000 miles each set. We have proved to prove out a satisfactory plug it takes 3 to 6 months. ------------oOo------------ M E 1227 (1000 2/28) EW Ltd. 70-12-25(1) 3241. | ||