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).
Engine timing adjustments and subsequent performance testing with accompanying valve timing diagrams.
| Identifier | ExFiles\Box 11\4\ 04-page095 | |
| Date | 12th July 1932 | |
| X7941. To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From G.W.H. Hotel de France, Chateauroux, FRANCE. 12.7.32. 19-EX. We enclose the timings of the engine as when it left Derby, and advanced one tooth here. (Camshaft E.82448) Left Diagram: Date: 26-6-32 TDC IO 3.83° EC/IO 11.16° EO 46.5° BDC IC 54.75° Right Diagram: Date: 10-7-32 IO 1.56° EC 4.650 TDC EO 54.4 IC 46.88° BDC The engine does not seem so smooth with the alteration to the timing. We enclose the acceleration figures taken after the timing was altered. The difference at high speed is marked, but in the previous test there was a head wind which pulled the performance down. We have found a suitable road for the maximum speed test, but we shall have to measure a half mile out, as there are no kilometre stones. We have not had much success with the Low Inertia Damper. The gear rattles came on again after 20 miles, the half speed period took longer, approx. 200 miles was run before it again appeared. The engine is very smooth and silky while it is cool, but when hot, it is no where near so good. The temperature figures of the rear of the car we enclose. It will be seen that we have not obtained much data for you. In my letter of the 11.7.32 I gave you the cause to be due to the excessive air temperature. You will see by the figures that there is only 5°C difference between the air temp, and in side the car. We tried with and without the shields, cut-out open, and cut-out shut, but the results were very disappointing. We will try again if the weather cools off. G.W.H. | ||