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).
Instructions for modifying hydraulic shock dampers on 20/25 HP & 40/50 HP chassis to reduce knocks.
| Identifier | ExFiles\Box 105\3\ scan0141 | |
| Date | 21th November 1930 | |
| COPY. RHC.{R. H. Coverley - Production Engineer} c. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} X8520. BY/HEB{H. Biraben}9/M.21.11.30. 20/25 HP. & 40/50 HP. Chassis. X.7520. X.5520. REDUCED CLEARANCE BETWEEN BALL VALVES AND STOP PINS ON FRONT & REAR HYDRAULIC SHOCK DAMPERS, TO REDUCE KNOCKS. REAR HYDRAULIC SHOCK DAMPER SEC:7150. FRONT HYDRAULIC SHOCK DAMPER SEC:7160. In accordance with Expl. Dept's instruction, the lift of the ball valves in high and low pressure passages for the Air Release, has been reduced to .010". This has been arranged as shewn on Scheme 1406, in two stages as follows :- (1) Modifying existing dampers for immediate change in Works. (2) A final modification also adding a Filter to each Ball Valve for future Production. We herewith send one Blue Print of each of the following details necessary for Item (1) which is being instructed to Works' immediately. F.83102 Valve Cover Plug. F.83129/30/31 Adjusting Screw (Ball Valve). F.83132 Washer (Adjusting Screw). Also one Blue Print of :- Scheme 1406 Shewing the modifications referred to above. Will you please instruct up the above parts as set out below for the various Dampers if required.- 40/50 HP. CHASSIS - REAR DAMPER HIGH & LOW PRESSURE VALVES SEC: 7150. F.83102 Valve Cover Plug. 4 off, which replaces F.81387 -4off F.83130 Adjusting Screw (Ball Valve) 4 off, which replaces F.79616 - 4 off. F.83132 Washer (Adjusting Screw). 4 off ADDITIONAL. Please note that F.83102 should be produced by adding a counterbore to the existing Plugs F.81387. We understand from Mr. Brock that the Plugs already fitted to Dampers cannot be modified, owing to the Countersunk screw F.79616 | ||