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).
Valve stretch and wear measurements after engine dismantling.
| Identifier | ExFiles\Box 43\1\ Scan055 | |
| Date | 19th August 1924 | |
| R.R. 493A (20H) (D.A. 652 20-8-24) J.B.D. -6- EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}3/LG19.8.24. The following figures were taken on dismantling the engine and denote how much longer the valves had become when compared with a valve correct to drawing. Note :- The drawing gives a + .025" limit, - and the tappets were given .030" clearance at the commencement of the test, and when readjusted. A.1. cyl. + .025 B.1. cyl. + .066 A.2 " + .002 B.2. " + .040 A.3 " + .087 B.3 " + .045 A.4 " + .016 B.4 " + .011 A.5 " + O.K. B.5 " + .030 A.6 " + .007 B.6 " + .007 As there is no record of length of the valves before the test, the accurate amount of 'stretch' cannot be given. The general condition of the valves is very good, and A.3. valve (which was the first to show the stretching) was very good considering it must have been off its seating for at least 15 hrs. On examination of the seatings A.3. and B.1., the seatings had collapsed and in each case it was the portion nearest to the centre of cyl. The valve guides show considerable wear, more on one side than the other and it appears as though the tappets were pulling the valve over. Pistons. As previously stated at the end of the 50 hrs. on the hangar and 10 hrs. on the bed, the pistons and rings were carboned up; after a further 40 hrs., the same condition existed. From the top of the pistons to the first ring there was contd:- | ||