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).
Test report on No. 2 Unit, detailing issues with valve noise, tappet assembly, and running performance.
| Identifier | ExFiles\Box 4\1\ 01-page243 | |
| Date | 8th September 1934 | |
| -2- No. 2 Unit received for test on the 2.8.34. and to specification RRC/WSC.{W. S. Cassel}10/EP.{G. Eric Platford - Chief Quality Engineer}8.34. This unit was fitted with R.R. lead bronze bearings both main and big ends; Ex.15042 camshaft and E.84846 pistons similar to No. 1 unit. It was noticeable on No. 1 unit that the inlet valves were quieter than the exhaust and the camshaft Ex.15042 was produced using the inlet cam form off E.85265 throughout. The valve noises on this unit were almost as bad as No. 1 and the same discrepancies of cam contour. There was a possibility of the tappet assembly pins preventing the tappets from going right down to the base circle of the camshaft. Actually this was the case, to the extent of .010 - .020 lift, thus cutting out the cam foot, both opening and closing, for after removing these pins, the valve gear was perfectly quiet with the self-adjusting tappets in operation. Likewise No. 1 unit was installed in the chassis without the tappet assembly pins, the valve gear being quiet. As in No. 1 unit and for the same reason of wedging eccentrics and lubrication troubles, the self-adjusting tappets were not satisfactory. Even slow running was obtained at 160-175 r.p.m. under load and 220-250 r.p.m. light running with the tappets as standard and run with a clearance of .005. Clearances in excess of this figure do not improve the slow running, but reverting to self-adjusting tappets which run at an approximate clearance of .001, the slow running light at the above speeds becomes unsteady. No power readings were taken on this unit as the bearings tightened up when run at full throttle. After 36 1/2 hours running the unit was returned to RHC.{R. H. Coverley - Production Engineer} on the 8.9.34. having been on test for 5 weeks. | ||