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).
Failures of a piston skirt, slipper wheel, and valve spring on a 'Bensport' vehicle.
| Identifier | ExFiles\Box 82\1\ scan0088 | |
| Date | 8th April 1933 | |
| To Hs.{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}; From G.W.H. E) Please Return By J XU P53a Hotel de France. Chateauroux. Indre. 8.4.33. M B E N S P O R T. We observed upon draining the sump after yesterday's mileage that pieces of a piston skirt had come out with the oil. There had been no sign on the road of anything unusual happening. We dismantled the bottom half and found that a section of the split skirt had broken off from the cross cut at the top to the bottom. We cannot account for the fracture. The material looks very coarse. We have carefully examined all the other pistons and there is no sign of any cracks. One remarkable condition we noted and that was, all the gudgeon pins had worked to one side of the pistons nearest the dash, and appeared to be pressing hard on the retaining ring, but the retaining rings had not moved. Nº4 piston had the scraper broken. This is the second time. The first time I thought may be they had cracked it in fitting, but it is not so. The fracture is at the approx. same place ie. one inch from the end. The bearings of the conrods now show cracks in the metal. These are of no consequence at the moment, but up to now there had been no sign of the metal fracturing. The cylinder block paper lining at base, had been broken up. It was in several pieces when we lifted the block off. We have had rather a bad oil leak from the base of the cylinder. SLIPPER WHEEL We have previously reported to you that the slipper wheel had cotton duck fabrics fitted. We dismantled the damper and found that the fabrics had almost been pressed to nothing. The load and the slipping had ironed the washers out so much that there was quite half an inch of the washers (circular) on the inside of the damper. The load of 27 lbs is altogether too much for the cotton duck, also we found that when we fitted new fabrics the springs were choc-a-bloc. One can understand the wear and the development of the half crankshaft period, with the slipper wheel fitted up under those conditions. VALVE SPRINGS Nº 12 valve spring that we fitted taken from the spares with the car, only lasted 500 miles. It broke two turns from the top. [STAMP: RECEIVED 15 APR 1933] 4 - 5 1/2 16 - 30 64 - 165 Then def 1/7 2 1/2 | ||