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).
Series of tests to diagnose and resolve engine chain oscillation issues.
| Identifier | ExFiles\Box 113\5\ scan0176 | |
| Date | 5th December 1936 | |
| -2- but not sufficient to overcome the tensioner, although oscillating to the fullest extent on the driving side. (2) 1900-2300 R.P.M. This is the same period as mentioned in test No.1., but is now more violent. Chain Oscillation. Test No.3. Fabroil block and chain tensioner removed. Chain tightened to 1/2" slack, by raising camshaft .075". (1) 1100-2000 ? Under this condition the engine was not run above 2000 R.P.M. as the oscillation was so bad that it was feared the chain might break. Test No.4. Flywheel Ex.25336 fitted to driven end of camshaft. Result. Same as test No.3. Running at 1500 R.P.M., it was found necessary to apply a braking load of 200 lbs on the rim of the flywheel to damp out the oscillation. This point merely serves to prove that the oscillation originates in the camshaft. Test No.5. Chain and tensioner returned to the conditions of test No.2.(Fabroil block now permanently removed). Driving springs removed from the slipper wheel (Crankshaft) and solid distance pieces inserted. This cut out the action of the spring drive. No flywheel on camshaft. Result. (1) 1100-1300 R.P.M. } (2) 1600-1750 " } All these periods overcome (3) 1800-2900 " } the tensioner. (4) 3700-4500 " } In this test a means was devised, by which the load of the tensioner on the chain could be increased at will. Up to now the tensioner had given a constant load of 10 lbs on the chain. The effect of increasing the tensioner load was as follows:- taking the first period in the speed range as being 1200 R.P.M. When the tensioner pressure was increased to 17 lbs, this period faded right out. Maintaining this pressure of 17 lbs the engine revs. were increased slightly, and the period came up again at 1450 R.P.M. in the following way. | ||