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).
Faults experienced with B.60 and B.80 units on the test bed, specifically concerning oil leaks from side tappet covers.
| Identifier | ExFiles\Box 124\1\ scan0271 | |
| Date | 28th November 1939 | |
| 1044 To Ev.{Ivan Evernden - coachwork} c. to Jnr.{Charles L. Jenner} Rm{William Robotham - Chief Engineer}/F.J.Hallam.10/JR.{Mr James Royce}28.11 39 FAULTS EXPERIENCED WITH B.60 and B.80 UNITS ON TEST BED. (1) Oil leaks from side tappet covers. These can be classified as two separate leaks. (a) From the cork joint around edge of cover. This was caused by the cork washer being too thin when compressed, allowing the metal lip of cover to come in contact with the cylinder block. This leak has been cured by fitting a thicker cork washer. (From .125" to .1562" when compressed). (b) From the face joint of cover nuts. When nuts are tightened with a spanner, the tappet cover is distorted and the face joint between the nut and cover is disturbed, thus allowing a leak to occur. This leak is aggravated by splash and pressure inside the tappet chamber. Nuts can be screwed in until end of thread on the stud is reached, causing a locking effect, so that next time the nut is removed it usually brings the stud with it. Strengthened type tappet covers (thicker material .048" to .064") do not cure this, a little extra pressure on a spanner will produce the same trouble. This leak is more evident on B.80 units, which have longer tappet covers with three retaining nuts to each. A mock up scheme of fitting distance pieces on the studs between cylinder block and tappet covers, which prevents the cover from being distorted inwards, has been tried with success. | ||