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).
Alterations and fire risk tests for a Stromberg carburetter D.C.42.
| Identifier | ExFiles\Box 122\2\ scan0003 | |
| Date | 17th April 1936 | |
| To E.{Mr Elliott - Chief Engineer} X1033 Hs{Lord Ernest Hives - Chair}/GR.{George Ratcliffe}3/KW.17.4.36. 21-G-IV. Unit C-15. The Stromberg carburetter D.C.42 on this car was fitted with the latest development of drain pipe and vent from the float chamber lid.{A. J. Lidsey} Alterations :- Bore of vent increased to .312" dia. " " drain pipe " " .250" " " " dixtamper " " .171" " This enabled maximum flooding to take place without overflowing open vent as fitted, an inch above float chamber cover. The open vent is an improvement on starting; i.e., when hot after standing 15 minutes. Sparking plugs K.L.G. 831 L.R., gaps increased to .025". This also gives slight improvement on starting and slow running. Numerous tests were carried out to see if engine would set on fire when hot with open vent on float chamber lid.{A. J. Lidsey} The worst conditions were eventually tried out as follows, without setting the engine on fire:- (1) Under bonnet temperature increased to 60°C. and 70°C. by packing all round with asbestos. (2) "Swan" petrol used and pumps switched on and off every other minute during stops of 10 - 15 & 20 minutes. (3) Radiator shutters disconnected and closed in order to collect as large a volume of petrol gas as possible under the bonnet. (4) Plug leads short-circuited to spark externally to the cylinder head and also to the top tappet cover nuts. The above tests were carried out in the open but not on the road. Hs{Lord Ernest Hives - Chair}/G.H.Ratcliffe. | ||