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 tapping issues traced to insufficient clearance in the fan pulley and an inspection of the slipper drive.
| Identifier | ExFiles\Box 101\2\ scan0119 | |
| Date | 17th October 1936 | |
| gvy copy. 509d HOTEL DE FRANCE CHATEAUROUX, Indre. France. GWH{George W. Hancock - Head Chateauroux}/IMW{Ivan M. Waller - Head of Chateauroux}/3/JAB‡ 17th October, 1936. To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to G.W.H. 22.G.V. Engine Front C.17. Ever since this unit was fitted, we have experienced tapping from the engine front when starting from cold. This was attributed to insufficient clearance for the oil retaining boss on the fan pulley. This has become worse of late so the engine front was dismantled. It was found that the four 1/4" bolts holding the slipper drive together, had pips on the ends which had rubbed a groove in the face of the engine front. They have been shortened so as to be flush with the nuts. This point should receive special note on all engines as the clearance is so small that a small amount of wear on the rear flange of No. 7 main bearing will allow the pressure due to withdrawing the clutch to push the ends of the bolts into contact with the engine front. The total clearance between the oil retainer on the pulley and the case was .010", i.e. .005" all round if the pulley remains central. It was however rubbed bright and very slightly scored all round, and there were intermittent marks on the case where it had touched. The opportunity was taken of examining the slipper drive. The rear driven face was slightly grooved, the other faces were free from scores and in excellent condition. The friction discs were also in good condition. The poundage was found to be 16 lbs. ------- GWH{George W. Hancock - Head Chateauroux}/I.M. Waller. | ||