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).
Specification comparison between Lodge 640 and Lodge 641 spark plugs.
| Identifier | ExFiles\Box 162\2\ img006 | |
| Date | 23th February 1940 guessed | |
| LODGE 640 REACH: 0.700" LENGTH OF BARREL: 1.000" LENGTH OF INSULATOR: 2.200" INSULATOR MATERIAL: SINTOX REMARKS: SINGLE & THREE POINT TYPES OBTAINED FOR TEST ON PH. III LODGE 641 REACH: .700" LENGTH OF BARREL: 1.300" LENGTH OF INSULATOR: 2.600" INSULATOR MATERIAL: SINTOX. REMARKS: SINGLE & THREE POINT TYPES, OBTAINED FOR TEST ON 25/30 & BENTLEY. Text on spark plugs: LODGE SINTOX MADE IN ENGLAND | ||