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).
Internal measurements and condition report for the main and big end bearings of Chassis B.74.GA.
| Identifier | ExFiles\Box 146\3\ scan0217 | |
| Date | 10th December 1936 | |
| 1265 To Bentley Motors Ltd. Derby ........Rm.{William Robotham - Chief Engineer} Levallois Sr/VA26/GM.10.12.36 re: CHASSIS B.74.GA - Mr. P. LE BLAN ----------------------------------------- As requested by you on the phone, we have taken, as far as it has been possible, the internal measurements of the main and big end bearings, which we give below: MAIN BEARINGS 1 2 3 4 5 6 7 Dia. 'A' 2"251 2"2525 2"2545 2"2535 2"250 2"2605 2"252 Dia. 'B' 2"251 2"252 2"251 2"2515 2"250 2"2585 2"2525 'A': Measurements taken vertically and 'B': measurements taken near the joint faces of the bearings. CONN.RODS 1 2 3 4 5 6 BIG END bearings: 2"003 X 2"004 2"0025 2"0025 2"002 We have again examined the main bearings and find that the surface of most of them is in a poor state. A certain amount of metal from n°. 2 big end bearing must have found its way past the filter, as small particles are imbedded in certain of the bearing surfaces. The bearings show distinct signs of having hammered in their housings. We have found most of the remains of N°. 2 big end bearing, which is in the form of small bits varying in size. Please let us know if you wish us to return the bearings and liners to you for examination. CRANKSHAFT: We are going to stone down the light grooves in the crankshaft journals and then lap each one on the machine in order to obtain a smooth surface. As you are aware we cannot remove the ovalisation which exists by lapping. We attach a sketch showing the existing measurements of n°. 2 crankpin. Do you consider that it should be reground ? We would prefer not to touch it apart from lapping it. (PLEASE NOTE FLAT ON PIN) In view of the above we confirm having telegraphed to you to-day as follows: ROBOTHAM CHASSIS BENTGA SEVENTYFOUR LEBLAN WE PREFER TO FINAL REAMER BEARINGS IN NEW UPPER HALF CRANKCASE TO SUIT CRANKSHAFT. ..... | ||