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).
Modifications and issues related to Chassis B-8-GA (Trials Car) and Chassis R-74-GA.
| Identifier | ExFiles\Box 146\3\ scan0255 | |
| Date | 18th December 1936 | |
| 1620 To Sr. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}4/JH.18.12.36.. Chassis B-8-GA (Trials Car). With reference to your memo: Sr/VA.24/GM.15.12.36. we have not had any trouble due to oil getting into the clutch through the drilling of an extra hole in No.7 rear main journal. The drilling of the extra hole in the main journals is we have found 'long and difficult' because the drills have to be reground often and the actual drilling carefully carried out. There is no secret or easier way of drilling other than the normal method. Our continued experience has shown that big ends in R.R.56 should have diametrical clearance limits between .002 and .0025. To complete the job on this car it would be as well to use an oil pump of increased capacity. Possibly you have one available for the job, as sometime ago we sent out half a dozen such pumps in conjunction with the lead bronze bearings. The oil pressure when hot should be 30 lbs/sq. at high speeds and certainly not less than 25/lbs.sq.in. at high speeds. The extra holes in the crank journals and the modified grooves tends to lower the oil pressure, notice should be taken when the car is again running that the pressure reaches this figure. If you have not got a large pump you may be able to get pressure by washering existing relief valve spring. We shall be interested to hear from you on this point. Chassis R-74-GA. With regard to the parts for the above these were sent off per our telegram. They include, | ||