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).
Results of heat treatment tests on Bentley pistons.
| Identifier | ExFiles\Box 86\2\ scan0164 | |
| Date | 24th November 1933 | |
| X-36 To E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} " By.{R.W. Bailey - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/KT.24.11.33; c. to Hl. BENTLEY PISTON HEAT TREATMENT. Replying to By18/C.23.11.33; We have now collected our final piece of evidence with regard to quenching from 450°. A set of the original pistons as fitted to the first fifteen cars ran 13,000 miles on the open Bentley which included a good deal of track work. These were removed and chalk tested, and were found to be perfectly sound. Exactly similar pistons, except they were quenched from 450° and had strengthened gudgeon pin bosses, were then fitted to the car. The attached blueprint shows their condition after 2,000 miles running. You will remember our other evidence is - (a) On the last 10,000 miles test the quenched pistons failed in 5,000 miles. (b) The life on the test bed of the quenched piston is five hours, unquenched fifteen, confirmed by repeat test. The results under working conditions, therefore, are conclusive. In view of the Stanton test it certainly seems that further investigation is justified. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||