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).
Report from J.B. Dixon to GWH detailing issues with valve gear, brake squeaks, and oil consumption on specific vehicles.
| Identifier | ExFiles\Box 103\2\ scan0153 | |
| Date | 10th July 1936 | |
| To. GWH.{George W. Hancock - Head Chateauroux} BENTLEY. London 10.7.36 Bentley Push Rods. 260 GA. 960 Miles. Valve Gear clicking badly. The small ball end of the push-rod had worn leaving a projection .006" approx. proud of the radius corresponding with the oil hole in the lower cup. This was also noticeable to a lesser degree on the ball ends of the rockers. The valve gear did not appear dry. Four rods N° 2,4,10,II were bowed .004", .007", .013", & .013" respectively. These were replaced and returned to Derby. This points to the fact that the material is at fault in this case or that the radius of the balls and cups were not equal causing bad bedding at first which has worn down leaving the projections in the oil holes. On another case, B.16.GA. this trouble was also noticeable but to a lesser degree, the car in this case having done 5,000 miles and was suffering from a heavy oil feed to the rockers. The area of the ball seems to me too small, but I will watch for other cases of wear on the balls and bowing of the rods. BRAKE SQUEAKS. B.16.GA. 5,700 MILES. This car came in with bad brake squeaks on all brakes. I checked up the poundage of the pilot shoes and found them O.K. at 60 lbs. The clearances under the pilot shoes averaged just under .010", one shoe in the NSR. being only a light .005". There was also evidence of the liners not being tight on the shoes especially on the NSR. top pilot shoe & main shoe where it was possible to insert a .010 feeler under the liner at the leading edge. I went out in the car after it had done a 100 miles oil consumption test. There were no squeaks with the exception of a very high pitched and almost inaudible squeak from the front. The car has been passed out. HEAVY OIL CONSUMPTION 16. G.A. When tested over 100 miles only recorded 400 MPG. The relief valve was seating badly and there was an excessive supply of oil to the rockers. The dummet washers on the valve stems were slightly worn. The relief valve was lapped in and another washer placed under the spring making a total of 5 and the packings were renewed on the valve stems. When again tested over 100 miles, 800 MPG. was recorded. The oil pressure 25 sq." against the previous 23 lbs. sq.". I had a query from Derby with regard to the use of ethyl and its effect on plugs when running in London, I have answered them direct. There has only been one case since the 850 KLG. plugs were fitted. J.B. Dixon. | ||