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).
Examination of a noisy and burst tappet on chassis 54-EX, attributing the issue to lubrication failure and proposing solutions.
| Identifier | ExFiles\Box 96\2\ scan0200 | |
| Date | 9th January 1937 | |
| 354 Redler BY.1/G.9.1.37. Hd.{Mr Hayward/Mr Huddy} RHC.{R. H. Coverley - Production Engineer} Mx.{John H Maddocks - Chief Proving Officer} Rm.{William Robotham - Chief Engineer} c. BY/CS. Swolf- NOISY TAPPET - CHASSIS NO. 54-EX. I have examined the tappet from the above chassis which is burst in the cup at the upper end, and agree with Mr. Bull that the cracking in the cup is due to the fact that owing to absence of lubrication at the ball surfaces sufficient wear has taken place to permit the edge of the cup to foul the lever when the valve is in its fully open position. Normally there is almost 1/10" clearance, and that represents the amount of wear which has actually taken place in the cup. At first sight I was inclined to think that the trouble had started with the automatic adjustment not functioning, but am satisfied that Mr. Bull's view is a correct one, viz. that the automatic adjustment has been functioning and the trouble is due to actual wearing away of the surfaces due to absence of oil. In another case which showed very considerable wear it was suggested that the surfaces had not been sufficiently hardened, but on an unworn portion which still existed we found that the brinell was as high as 750, a figure which is perfectly satisfactory providing lubrication is present, and I therefore infer that in this case it is not a question of hardness but absence of oil. I wish to confirm that we have arranged for a groove to pass down the face of the ball to enable oil which is flashing about to get between the operating surfaces, which should cure the trouble. At the same time we do not feel happy so long as the hole which conveys oil from the rocker shaft to the rocker lever is absent. We are awaiting experiments in the direction of packing the hole in the tappet end of the rocker lever with worsted or felt. BY.{R.W. Bailey - Chief Engineer} | ||