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).
Valve tappet clearance and crankshaft damper failures and testing.
| Identifier | ExFiles\Box 124\1\ scan0127 | |
| Date | 22th May 1939 | |
| -4- Valve Tappet Clearance. Running with sodium filled exhaust valves and "Brichrome" inserted seats, the clearance maintained throughout the run with only a maximum variation of .002. On the O we have established that this result is independent of the sodium filling. A check could not be kept on the inlet valve clearance on account of periodic valve spring failure and the necessity of removing the rocker shaft. FAILURES. (1) Crankshaft Damper. Commencing with the R.R. Harmonic, this siezed on its bush after 3 hrs., was corrected and again siezed after 9 hrs., this being re-assembled with a definite clearance of .010-.015 similar to Buick principle. After a total of 18 hrs. the majority of the leaf springs were found broken and rusted up despite the fact that they had been packed with grease during each attention to the damper. In view of the continual damper trouble it was decided to fit the Studebaker damper and with this the run was completed without further trouble in this respect. It was noticeable, however, that with the Studebaker damper the engine was much rougher. Since running the endurance we have registered the crankshaft oscillation with both the R.R. harmonic damper and the Studebaker damper on another B.80 unit. The result is that up to 4500 r.p.m. (the maximum speed) with the R.R. harmonic damper the crankshaft oscillations never exceeded .5°, whilst the Studebaker at its endurance setting registered up to 1° amplitude. By tuning the Studebaker damper, i.e. varying the hardness of the rubbers, the oscillations can be brought down to the R.R. harmonic figures. Continued. | ||