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).
Engine component modifications and test results, focusing on oil feed, plungers, and springs.
| Identifier | ExFiles\Box 106\5\ scan0104 | |
| Date | 12th September 1932 guessed | |
| -2- At present this appears to be working satisfactorily, but until we have run more mileage we cannot say definitely that it is a 100% job. The removal of the oil feed hole from the eccentric necessitated a new feed of oil to the plungers, and this was done by drilling an inclined hole .1562" dia. from each pedestal to each plunger housing. With this scheme we found that we could return to the scheme of 2 rocker feeds instead of 4, because the extra restriction to the oil flow, i.e.- only .001" clearance between the plunger and the plunger housing meant that the same oil pressure was sufficient to feed all the plungers, whereas previously the oil flowed so freely out of the eccentrics nearest to the main feed hole, that none was left to reach the extreme ends of the rocker shafts. With regard to troubles (b) and (c), the D.O. supplied us with a plunger LeG.3540, incorporating a ball valve to replace the poppet valve, and from the first fitting of these plungers they seem to work O.K. Regarding trouble (d) we tried another plunger spring E.59630 of less stress giving a 3.75 lbs. working load instead of E.58932, also giving a working load of 3.75 lbs. and no breakages have occurred as yet. The next trouble we ran up against was an inadequate oil feed to the plunger housings when the oil was cold, and the lack of a reservoir of oil on the top of the plungers themselves. It is essential that we have an ample reservoir of oil in the plunger housing to replace the oil lost through leakage, and thus ensure the immediate correct working of the plunger when starting the engine up again after it has been stopped for some time. This was done by fitting a set of plunger housings .100" taller and carrying the inclined feed hole nearer to the top of the housing, thus slightly reducing the restriction to the oil feed and retaining a .100" deep reservoir on top of the plunger. We also examined the tappet springs E.57708 and found that several were broken. A new set of similar springs was fitted and these also broke after a few hundred miles running. These were then replaced by a set of E.59646 lower stressed springs and no breakages have occurred yet after approx. 1500 miles running. When examining the bottom tappets we found that there was no locking device to the nut holding down the bridge piece, and that several of the nuts had worked loose. Also the bridge piece itself E.57693 was not | ||