Letter from English Racing Automobiles Ltd. discussing Bosch spark plugs, cylinder head performance, and sticking exhaust valves.
| Identifier | ExFiles\Box 162\3\ img118 | |
| Date | 11th May 1938 | |
| 6000 E.R.A ENGLISH RACING AUTOMOBILES LTD BOURNE LINCS DIRECTORS W.H. COOK RAYMOND MAYS PETER BERTHON TELEPHONE BOURNE 121 OUR REF. PB/JB. YOUR REF. DATE 11th May, 1938. MANUFACTURERS OF "E.R.A." RACING CARS MURRAY JAMIESON SUPERCHARGERS AUTOMOBILE RESEARCH ENGINEERS CUSTOMERS' CARS ARE DRIVEN BY OUR STAFF ONLY AT CUSTOMERS' OWN RISK S. W. Grylls, Esq., Messrs. Rolls Royce, Ltd., DERBY. My dear Grylls, Further to our 'phone conversation to-day I have arranged for a sample Bosch Plug type 440G4 to be sent you and also the next hottest which is 500G4. Bosch can supply one grade hotter which is a 520G4 but I am afraid we have not any in stock. The best brake M.E.P. we can hold is 384 at 55/6,000 revs. and the plugs used are 480 on test and usually 440 (a grade lower) in races on twisty circuits. We have been up to 420 brake M.E.P. but cannot hold it as the Cylinder Head won't stand for it. We have, however, a new head coming through which we think will help. Many thanks for your information on the gearbox gear material etc. There is one other point which I know you could let us have some valuable information about. We are in trouble with exhaust valves sticking and presume our only means of overcoming this is to use valves with nitrided stems. I believe also that Brightray has been successfully applied. The valves are of course sodium filled and any information you could let us have with regard to the procedure of manufacture with both Nitriding and Brightray will be most valuable. Don't forget to ring us up about coming over. Yours sincerely, [Signature] AND AT BROOKLANDS TRACK, WEYBRIDGE, SURREY | ||
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).