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).
Recommendations to address engine overoiling and oil consumption issues on car 3-AZ 170.
| Identifier | ExFiles\Box 115\1\ scan0244 | |
| Date | 5th January 1937 | |
| 6 1020 To Hd.{Mr Hayward/Mr Huddy} Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}9/JH.5.1.37. 3-AZ 170. With regard to the top overoiling of the above car and consequent oiling up of the plugs we recommend that you carry out the following. (1) Fit 4 felt pellets as supplied by us in the valve end of each rocker, retaining the .015 hole in the tip. (2) Fit new valve stem packings and when fitted check for valves not being choc-o-bloc in the full cam lift position, otherwise damage will be done to the bottom tappets. (3) Groove to be made .025 radius vertically in the top adjusting screw and the bottom ball end of the push rods. (4) Drill 1, .015 dia. hole in the annulus of each floating rocker bush (Bronze). With regard to the bad oil consumption in view of the latest test carried out by Mx.{John H Maddocks - Chief Proving Officer} on 3-BU-80 in which no improvement was effected by the fitting of L section piston rings it does not appear to be worth stripping down the engine to fit these. It is a well known fact that hard driving does improve the oil consumption and we suggest that the consumption run which you carried out over 120 miles may have contributed to this effect. If however on your next run there is no improvement in the consumption figure and it is too bad to return to the customer i.e. under 500 miles/gallon, then the engine will have to be stripped down. Before this is done however we should like to see if the alteration to be valve gear oiling has cured the low speed overoiling and plugs misfiring. Prior to carrying out the next oil consumption run the oil temp. regulator might be pressure tested the main oil pressure checked at high speeds when the oil is hot. It is not necessary for the oil pressure to exceed 30 lbs/sq.in. under these conditions and if it is higher then some improvement might be effected if this be dropped to 30 lbs/sq.in which is the designed figure. | ||