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).
The implementation of AC2 bearing material and modified drilling on 4 1/4 litre Bentley engine crankshafts.
| Identifier | ExFiles\Box 114\3\ scan0063 | |
| Date | 5th September 1938 | |
| GWH{George W. Hancock - Head Chateauroux}(Kingsbury) AC2 Bearings LA{L. A. Archer}8/T5.9.38 re. 4 1/4 Bentley - Engine Bearings With reference to our conversation last week and your request to know when the modified drilling commenced on Bentley Crankshafts. You will remember I told you that the modified drilling started at the same time as the fitting of AC2 material. I find on going further into this matter that this is not quite correct, as the following 9 chassis left the Works fitted with AC2 material, but only one hole in the crankpin. B-149-KU 157 159 B-163-KU 165 169 B-171-KU 173 B- 85-GP + I also attach herewith a list of the 78 Bentley Chassis which left the Works fitted with AC2 bearing material. One or two of these chassis have since had the bearing material changed to AC7 and Whitemetal No.7 bearing, and I have marked these numbers with a cross on the list. You will notice that at the end of this list there are 4 chassis, two of which are early in 'K' Series, one in 'G' Series, and one in 'H' Series. The reason these chassis have engines fitted with AC2 material is, that at the time we had chassis on test fitted with the AC2 material bearings we had to supply to the Repair Dept. four engines to enable them to redeliver cars quickly to customers whose engines had broken down. You will notice also that the 9 chassis mentioned above which were fitted with AC2 material and only one hole in the crankpin, are also on the enclosed list. With the exception of these nine chassis, you can take it that the rest of them have the modified drilling to the crankshaft. I hope this will make the position of the AC2 material and the modified drilling quite clear. LAh | ||