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).
Investigation into an engine thud and knock on chassis B.125.GP.
| Identifier | ExFiles\Box 114\3\ scan0083 | |
| Date | 30th May 1938 | |
| To Bentley Motors Ltd. Derby.......... Ev.{Ivan Evernden - coachwork} Copy to Rm.{William Robotham - Chief Engineer} Hd.{Mr Hayward/Mr Huddy} Levallois Sr/VAII/ET.30.5.38 Re: CHASSIS B.125.GP - Mr. J.{Mr Johnson W.M.} FAURE "Complaint of thud and knock in the engine". With reference to Sr.'s conversation with you during his last visit to the Works, concerning main bearing trouble having developed in the engine of the above car after we had carried out all known modifications, the following is our report: The car was sent to us on 3.1.38, at 18.437 miles, with a complaint of engine roughness. We found the engine to be very rough and there was also a bad thud in it. We carried out all known modifications, viz. Drilled crankshaft. Stoned and polished the main journals. Fitted new main bearings with a white metal bearing to the rear. Gave a .002" nip to all bearings. Please refer to Owner's Complaint Report No P.42. During the testing of the car, we found that the thud had disappeared, but there was still a certain amount of roughness, though to a lesser degree, which we thought was coming from the slipper drive. The car was sent to us on 4.4.38, after having covered 22.868 miles, with a complaint that the engine knocked between 1200 and 2000 r.p.m. On removing the bottom half and upon examination of the lower halves, we found that Nos. 2, 3 and 4 main bearings had picked up, owing to partial seizure. As the owner was absolutely in need of his car, all we could do in the time was to scrape the lower halves and carry out a temporary job. After doing this, the knock was not so pronounced; the engine, however, was still rough. It was agreed by the owner that he would let us have the car for further attention as soon as he could possibly spare it. The car has been sent to us for attention again as the owner did not need it for about two weeks. The total mileage is 23.875 and the car has covered 5438 miles since we modified the engine. Upon dismantling the engine, we found the following: | ||