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).
Bearing clearances for the Chassis B.8.GA Paris Trials Car.
| Identifier | ExFiles\Box 146\2\ scan0067 | |
| Date | 15th January 1937 | |
| Handwritten: Le iley Swell To Bentley Motors Ltd., Derby..........Rm.{William Robotham - Chief Engineer} Levallois Sr/VA6/ET.15.1.37 Re: CHASSIS B.8.GA - PARIS TRIALS CAR. --------------------------------------- Sr. Mentioned to me this morning that you would like to be assured that we gave sufficient clearance to the RR.56 big end bearings and rear main bearings. As mentioned in our VAI/ET.30.12.36, we left .004" end float on the rear bearing, plus from .003" to .00325" on diameter. To make sure that the clearance on diameter was correct, we passed a plug gauge of 2.250" diameter through the bearing. The maximum and minimum diameter of N°7 main journal of the crankshaft was: maximum: 2.2475" minimum: 2.247" = ovality .0005". We left the rear bearing so that the 2.250" plug gauge was a very free fit. We did not have to touch the big end bearings, apart from fitting them. However, before fitting them, we tried each one on a plug gauge which indicated that there would be a clearance on diameter of .00225". We noted from your memo Rm{William Robotham - Chief Engineer}/Sdl.4/2P.19.II.36 that the big end bearings had been reamered out to 2.0008" and were thus suitable for a crankpin having a diameter of 1.999". As the crank-pins on this car have a diameter of 1.9985 and the big ends were reamered to 2.0008", we have a clearance of .0023". Sr/VA.Vd | ||