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).
Investigation into noisy tappets on the Phantom III, caused by wear and oil shortage on the adjusting screw's spherical pad.
| Identifier | ExFiles\Box 130\2\ scan0290 | |
| Date | 18th November 1936 | |
| 1113. To Sg.{Arthur F. Sidgreaves - MD} Hs.{Lord Ernest Hives - Chair} E.{Mr Elliott - Chief Engineer} By.{R.W. Bailey - Chief Engineer} Rm.{William Robotham - Chief Engineer} Hq. GWH{George W. Hancock - Head Chateauroux}4/R.18.11.36. PHANTOM III. Complaints of noisy tappets will arise on Phantom III due to the wear of the spherical pad of the adjusting screw. We had to bring 35-EX back to the Works from test because of tappet noise. The adjusting pads had worn, together with the cups of the push rods to an extent that all the hydraulic plunger adjustment had been taken up. Upon examination, we found a similar case with the London Trials car 3.AZ.22 after a mileage of 7,900 12 push rods and rocker adjusting screws had to be replaced. The trouble is due to shortage of oil on the spherical contacts and the adjusting screw pads, also the question of hardness of the pads To overcome this trouble, on 35-EX we have drilled a .015 hole in the floating bush of the rocker to increase the supply of oil, but to prevent smoking of the exhaust we had to block up entirely the valve end of the rocker. The rocker adjusting pads were drilled down the centre with an annulus in the thread to collect the oil. A bench test was carried out with the present standard oiling scheme of the rocker and with the .015 hole in the floating bush, the supply to the rocker pad was increased considerably. The first scheme has run 1100 miles in London traffic (the low speeds being the worst condition for this trouble). The condition and lubrication of these parts were 100%. We are trying out the original scheme of lubrication to the pad, but with increased oil supply; this is to enable us to overcome the trouble on existing cars, and if satisfactory, it will not be necessary to alter the design. By.{R.W. Bailey - Chief Engineer} is investigating the quality of hardness of the spherical pads. GWH.{George W. Hancock - Head Chateauroux} | ||