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).
10,000-mile test of a 4-B-IV Bentley, detailing the performance of the engine, pistons, clutch, and gearbox.
| Identifier | ExFiles\Box 82\2\ scan0026 | |
| Date | 5th March 1934 | |
| To Ag. From Hs{Lord Ernest Hives - Chair}/CMH. c. to Wor.{Arthur Wormald - General Works Manager} c. to K.{Mr Kilner} c. to Dy.{F R Danby} c. to Ds. c. to Ldy. c. to V.{VIENNA} c. to Bn.{W.O. Bentley / Mr Barrington} c. to Rf. c. to Mx.{John H Maddocks - Chief Proving Officer} X45539 Hs{Lord Ernest Hives - Chair}/CMH.4/KW.5.3.34. 4-B-IV - BENTLEY - 10,000 MILES IN ENGLAND. REPORT ON THE CHIEF ITEMS THAT WERE TESTED. ENGINE. Started up without trouble under adverse conditions. Misfire with Lodge K.335. Power has remained up to standard throughout the mileage. Valves: No. 1 exhaust valve was removed because of stretching. The remaining valves were not affected to the same extent. It is essential to keep the valve clearance, 1. - .004", 2. - .006" cold. AEROLITE PISTONS. Slight knock at the beginning of test when cold, quickly disappeared and no further knocks were heard. The pistons were in a very good condition when dismantled and examined. They have been re-fitted for a further 10,000 miles. Previous to this mileage the pistons had run 19 hrs. Piston Endurance and 2,000 miles on 4-B-IV previous to the test. CLUTCH. The clutch pedal came up to the boards after 7,000 miles due to wear of the fabrics. The pedal retained its setting for the remainder of the mileage. The clutch has been smooth in engagement. There has been no noticeable slip during the test. GEARBOX. Ease of change was consistent. 1st, 2nd and 3rd gears in mesh were up to standard for quietness. A backlash developed half way through the test which caused a knock in the transmission. Considerable wear was found on the thrust washers and end of gears of the third motion shaft. The shaft was also worn where the ball races fitted. The D.O. have investigated the wear, and modifications have been instructed. | ||