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).
The wear and condition of various engine components.
| Identifier | ExFiles\Box 180\M3\M3.5\ img026 | |
| Date | 25th September 1924 | |
| R.R. 493a (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF: Valves. No valves appear to be cracked. Average wear on stems .0025". Hardened tips O.K. Felt washers quite hard and easily breakable becoming ineffective as lubricators with a possibility of extra oil getting down to piston head. Carbon deposit rather excessive on inlet valves. Cylinder blocks. Water tested and found O.K. (copper tubes fitted) At the end of piston stroke there is quite a noticeable 'step' on the none pressure side of bore. See inspection report on sizes of bores. Camshaft and Bearings. Slight wear on cams by rollers but not excessive - bearing surfaces O.K. Bearings tried on shaft and in crankcase, no appreciable wear - condition good. Rocker shafts. Slight wear on rocker arm faces due to rolling action on valve end. Wear not excessive - rocker shafts O.K. Pistons. No hard places on skirt of piston. All piston rings correctly bedding and free in piston grooves. There was a slight wear on gudgeon pin holes of .0005". These were not latest fitting. Gudgeon pins O.K. Pistons fitted after 5,200 miles running. Tappets. The holes in tappet, where roller pins fit, appear to wear more than the roller or roller pin. No appreciable wear on tappets or in the guides and no score marks on rollers. The coils of No. 11 spring had been rubbing on side of guide (spring not square). Push rods. O.K. No taper pins loose and they do not require stretching. Oil pump. Slight score marks in bore where driving gear shaft fits, wear in bore does not exceed .0005". The driving gear is scored on shaft corresponding contd :- | ||