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).
Bent push rods on the 20 HP model, specifically regarding insufficient valve spring clearance and incorrect tappet adjustments.
| Identifier | WestWitteringFiles\J\May1923\ Scan25 | |
| Date | 30th May 1923 | |
| TO B.J. FROM R.{Sir Henry Royce} c. to G.J. c. to B.Y. c. to H.S. c. to F.P. ORIGINAL R1/M30.5.23. 20. HP. BENT PUSH RODS. X4226 X RECEIVED In reply to your memo. BJ11/H25523., probably the clearance as actually made in valve spring or somewhere is insufficient, and can, and should be increased to one tenth [1853] of an inch minimum. A thick felt washer would make it wrong. Probably the fault reported is due to adjusting the tappets when the valves were not seating properly, in which case the adjustment would be so high that the valve would jam either in the springs or elsewhere. Cast on the top of the valve cover these instructions (or something better) :- "DO NOT READJUST VALVE" "TAPPETS UNLESS SURE" "VALVES ARE SEATING" "PROPERLY". We have tried and cannot re-arrange valve adjustment so that it cannot come out more than clearance allowed in valve mechanism. Carry spare rods. All rods are to be exactly the same length, and if changed cause no harm. All known valve mechanisms with adjustment have this trouble. We have a new scheme where the adjustment is limited naturally. R.{Sir Henry Royce} | ||