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).
Engine wear, repairs, and investigation into an overoiling complaint for chassis II5 MC.
| Identifier | ExFiles\Box 47\1\ Scan348 | |
| Date | 10th October 1926 | |
| IO.IO.26. Report on chassis II5 MC. The following is a report of the condition of the engine re wear before repairs, also the work carried out to prevent cylinders overoiling (complaint of overoiling by customer). Two sets of "L" type rings were tried before we decided to dismantle entirely the engine. The above rings made an improvement, but not to our customer's satisfaction. We dismantled the bottom half of crankcase and rigged up an arrangement consisting of an oil pump and special fittings so that we could force oil into the oil circulation and note the drip from all bearings, at a pressure of 27 lbs. per. sq. in. and an oil temp. of approx. 50°C. The flow of oil was found to drip more quickly from the inter. bearings than from the main. Also the oil dripped fairly quickly from the conrod bushes. The fastest flow of oil came from the inter. bearings N°s 2 & 3 and 5 & 6. We came to the conclusion that the latter was the cause of the engine overoiling, owing to the oil being thrown up into the cylinders N°s 2 & 5 from the crank webs. Cylinders N°s 2 & 5 were the ones found to overoil the most. We then decided to dismantle completely the engine, and examine all bearings for wear. We measured crankshaft journals and all bushes for wear (for dimensions see separate sheet and sketch attached). All bearings were found to have a thin layer of what appeared to be turkeystone powder embedded in the white metal. The Woodruff key on the front of the crankshaft was found to be sheared, and the spring drive hub had moved about 1/8y of a turn before seizing up on the cone. All bearings were scraped and the crankshaft rebedded, the latter taking longer than was expected, owing to the wear on the sides of all bearings near the liners. A good bedding job was made of all bearings. Bearings of conrods were found to be very slack. Engine was built up, remounted in chassis, turned and tested. Cylinder oiling was found to be absolutely O.K., and engine gears silent. The attached sheet gives a list of the jobs carried out. P.T.O. | ||