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).
Clarifying the testing status and development issues with the Big Bore Bentley and model 6-B-IV, specifically regarding bearing and piston failures.
| Identifier | ExFiles\Box 83\1\ scan0070 | |
| Date | 14th December 1935 | |
| To Eg. & Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to Ev.{Ivan Evernden - coachwork} HS{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}4/KW.14.12.35. Big Bore Bentley and 6-B-IV. We have been repeatedly asked when 6-B-IV is going to start its 10,000 miles test, and should therefore like to clarify the present position of the big bore Bentley. B-56-BN{W.O. Bentley / Mr Barrington}, went to France to prove out the chassis components which can only be tested by road work; i.e., the results indicate that the axle, gearbox, clutch, etc. were up to the big bore unit. The failures which occurred in the unit, which were the bearings and pistons, were discovered on the test bench soon after the car left Derby and long before it completed 15,000 miles. The two major troubles resolved themselves into pistons and bearings. It is no good starting 6-B-IV on a 10,000 miles test until we have got bearings which will stand up on the test bench. The reason for this is that the ideal place to test out bearings is on the bench and we have got an exact value for the time which the bearings must last under these conditions if they are to go through a 15,000 miles test. Though we have run several hundred hours on bearings of different sorts, we have not got any yet that are good enough though we are making progress. As we never know what trouble we are going to run into, it is impossible to give a date for 6-B-IV which would mean anything, but everything is ready except for the bearings and as soon as these are available the car can be released. In the interval we have added one or two items to the specification, which now reads as follows :- | ||