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).
Specifications and testing procedures for spark plugs, including gap setting, mechanical tests, and gas leakage.
| Identifier | ExFiles\Box 58\2\ Scan108 | |
| Date | 1st April 1934 guessed | |
| -4- (b) For the purpose of setting the gap to discharge at any voltage given in the table, a cylindrical "Go" and "Not Go" gauge of appropriate dimensions shall be used. The "Not Go" end of the gauge shall not exceed the dimension given in the Table; the "go" end of the gauge shall allow a tolerance of 0.05 mm on the setting of the gap. 14. Report on Tests and Drawings. A complete report on the tests specified in clauses 17, 18 and 19 shall be prepared and certified by the makers of the sparking plugs in the manner requested by the authorised representative of the Secretary of State. For record purposes, 5 copies of a sectional general and dimensional arrangement and detailed drawings to twice full scale, together with the material schedule and the type test report, must be submitted to the Director of Technical Development. 15. Special Tests. In the case of special designs of sparkingplugs, special tests may be made as decided by the representative of the Director of Technical Development. Section 3. Type Tests. 16. General. Any type of sparking plug shall before being approved for general use on any Service engine, satisfactorily complete the following series of type-tests :- (a) Mechanical Clause 17. (b) Gas Leakage " 18. (c) Electrical " 19. (d) Engine " 20. 17. Mechanical: Twisting Moment Test on Sparking Plug Body Thread. Three sparking plugs shall be submitted to the following test :- The sparking plug shall be screwed into a standard sparking plug hole, the form and dimensions of which are to be in accordance with B.S.Specification No. E.9. and the material of steel. The twisting moment applied to the hex-on nut on the body, which is necessary to fracture the screw thread shall be obtained and shall not belexss than 60 lb. ft. 18. Gas Leakage. (a) Six sparking plugs shall be tested for gas leakage at 600 lb. per sq.in. Each sparking plug shall be subjected to this pressure at atmospheric temperature and the gas leakage measured at atmospheric temperature and pressure. The sparking plugs shall then be tested at 200°C. and the leakage again measured at atmospheric temperature and pressure. After the preceding tests each sparking plug shall be again tested at 600 lb. sq.in. at atmospheric temperature and the leakage measured. The leakage throughout thesetests must not exceed 15 c.c. per minute measured at atmospheric temperature and pressure. | ||