Test drive report on experimental car 35-EX (a P.III), comparing it unfavourably with a Cadillac V.8 and highlighting issues with engine detonation, obtrusiveness, poor fuel consumption, and roughness
| Identifier | ExFiles\Box 96\3\ scan0043 | |
| Date | 13th January 1936 | |
| C. Mx {John H Maddocks - Chief Proving Officer} x360 H3 To Ros. from Sg. {Arthur F. Sidgreaves - MD} Copy to E.Hs. {Lord Ernest Hives - Chair} Hr. G.Cr. {Mr Cra’ster / Mr Chichester} re 35-EX. P.III. Sg {Arthur F. Sidgreaves - MD} 2/E13.1.36 I tried the above car this week-end, which was, I think, my first opportunity of giving a P.III a real run as distinct from trials on the bypass roads or short drives from Derby to Nottingham. I was very pleased with the riding, the brakes, the clutch, the steering and its freedom from joggles, although I thought it rather on the heavy side. I am sorry to say that I was disappointed with the engine. After my trial of the Cadillac V.8 last week I found the P.III engine definitely more obtrusive under all conditions of pulling. I also found that it detonated very freely when picking up from low speeds - in fact I do not consider that the amount of detonation is passable. I am also sorry to say that the obtrusiveness or fuss - or whatever one likes to call it - of the engine is greater on this car than on my 20/25 with the bored out engine. The [unclear] petrol consumption over a run of about 180 miles worked out at 8 1/2 and I am told that over a longer distance, i.e. 1200 miles, it has worked out at 8.7. I hope that with the downdraught carburetter the petrol consumption is going to be considerably better as we shall, I am afraid, receive a lot of complaints if the petrol consumption is much worse than P.II, i.e. 10 or 11. I understand that we are meeting Rm. {William Robotham - Chief Engineer} with 35-EX on Thursday and, if any one does not agree my views about the engine, I should be very pleased to demonstrate it as we shall bring 35-EX along. There is a definite roughness in the engine at about 50/60 which is sufficiently noticeable to show itself in the dither of the dashboard mirror. As we have been told on many occasions that the 12-cylinder is the ideal, I should be glad to know how we propose to make it ideal on this car. Sg. {Arthur F. Sidgreaves - MD} | ||
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).