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).
Proposed modifications and tests for engine valve gear and valve seats.
| Identifier | ExFiles\Box 134\2\ scan0128 | |
| Date | 14th July 1937 | |
| -2- (2) Venturi Valve Seats These should be tried out on the alum. high pressure heads, using a 1.750" valve and also a 1.600" valve. Provision should also be made for replacing the 1.600 venturi seat with a plain seat, and the best scheme might be a new head with the pattern modified in the inlet port. We are also anxious to try this type of seat in the standard Bentley unit, and suggest a modification to the existing head if possible. (3) Modified Valve Forms. Following on a visit to H.R.Ricardo & Co., at Shoreham, it was suggested that rather different valve forms to those we have been using up-to-date be tried. We should therefore like to try these forms as sketched in report Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards}7/R.14.7.37 on both the standard Bentley and the high power units. (4) Lightened inlet valve gear. The inlet valve gear on the High Power Unit is rather heavy and we suggest a rather lighter one be tried incorporating- (a) Lighter valve with reduced stem diam. (b) Aluminium or Duralumin top washer. (c) H.{Arthur M. Hanbury - Head Complaints} section rocker in duralumin, no bushing being used, the dural bearing straight on to the steel rocker shaft. Copper plating might be tried. (d) Tube type push rod in duralumin, with cups at both ends and an oil hole through each cup to allow lubrication at the bottom. (e) Use old Bentley type of rubbing bottom tappet, eliminating the cup on top, and simply having a ball end to take the bottom of the push rod. (5) Exhaust Valve Gear. On the main engine, we are using direct acting tappets with a .400" lift. on the cam. We should like this scheme adapted to the single, if possible, even if a new block has to be made. If this latter is the case, it should be as exact a copy of the main engine as is possible. Jnr.{Charles L. Jenner} will supply particulars. continued | ||