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).
Modifications to the 20 HP chassis valves and fittings to prevent fouling of rocker arms.
| Identifier | ExFiles\Box 48\4\ Scan115 | |
| Date | 5th September 1923 | |
| X4226 c. to Hs.{Lord Ernest Hives - Chair} BY/Shn7/DB.{Donald Bastow - Suspensions}5.9.23. RE 20 HP CHASSIS - VALVES & FITTINGS - SEC:5060. The Test Dept: have pointed out to us that when the Top Valve Spring Washers bed themselves on the split cone wedges, in some cases the rim of the washer fouls the underside of the rocker arms. We have added a note on the rocker arms drawings for the underside profile adjacent to the valve end to be cleaned up and tested by gauge before erection. We have also increased the large end dia: of the wedges by .005, which will allow them to stand .030 proud of the washer face before bedding in takes place; at the same time we have called for a smooth surface on the bore of the wedge and on the taper neck of the valve to obtain a good bedding initially. Care should also be taken to produce the 1 in 6 taper between valve and wedge and the 1 in 4 taper between wedge and washer accurately, so that bedding takes place throughout the full length of the wedge. We suggest that the Works produce at once some of the wedges with the increased dia: to deal with urgent bad cases; but care must be taken to keep the valves washers and wedges on any engine interchangeable, as well as the spare parts. With the 45° seated modified valves, raising the end of the valve .045, the danger of the valve spring | ||