Pete Lewis Posted February 3, 2018 Report Share Posted February 3, 2018 only from what happed on my Vit6 , timming check showed up 'a whys that changed' , it ran as good as ever but the marks showed something like 20deg of change had taken place , it was cleaning the damper ring to re mark the marks and it could rotate well move with hand pressure , should have kept it as a rouges gallery and it would be yours but as said it got binned like many bits end up and you want it later on, Pete Link to comment Share on other sites More sharing options...
dave.vitesse Posted February 3, 2018 Report Share Posted February 3, 2018 John, you are probably aware the 2.5 litre damper is larger than the 2 litre. Which with the longer stroke of the 2.5 is of course logical. Also as a result the pointer on the 2.5 timing chain cover is higher up. I don't have any measurements easily available at the moment. Due to the 2.5 damper being larger, for the same size pulley, it may be more vulnerable to un-bonding. Dave Link to comment Share on other sites More sharing options...
JohnD Posted February 3, 2018 Author Report Share Posted February 3, 2018 Indeed, dave! The damper is designed to each engine design, so it coincides with the 'node', the vibration harmonic of that engine. I have a small selection of damper pulleys, from 2 and 2.5L engines. The 2L outer ring is 130mm OD The 25Ls are 140mm OD All are based on a hub that is 112mm OD, with the rubber ring outside that. It is the mass of the outer ring that matters, to allow it to resonate with the vibration, so Triumph just fitted a thicker ring on the standard hub for the bigger engine. But the diameters are suspiciously 'round'! I suspect that their diameters were chosen, not by careful calculation of the nodal frequencies, but by some 'rule of thumb'! I'll know more, and share it, when I done the calculations! John 1 Link to comment Share on other sites More sharing options...
PeteH Posted February 6, 2018 Report Share Posted February 6, 2018 Some very large marine engines, are prone to vibration "node"s?. And resort to using both torsional and axial damping systems. Very often there is also a "barred speed range" which is quickly passed through when manoeuvring. Pete Link to comment Share on other sites More sharing options...
Ben Caswell Posted February 6, 2018 Report Share Posted February 6, 2018 Would the weight of the thicker flywheel make any difference the weight of the front pulley. I vitesse "ised" a saloon engine and both the flywheel and front pulley were considerably heavier on the saloon?? Link to comment Share on other sites More sharing options...
JohnD Posted February 6, 2018 Author Report Share Posted February 6, 2018 Yes, the mass of the flywheel does influence the frequency of vibration, and the mass of the indiviudal parts of the crank. and I believe that a 2.5L crank is 25% heavier than the 2L - off top of head that is! Saloon flywheels are heaviest of all. On my, currently 2L Vitesse, I've got the flywheel down to 7Kgs. Fingerscrossed about the damper! JOhn Link to comment Share on other sites More sharing options...
daverclasper Posted March 4, 2018 Report Share Posted March 4, 2018 Very interesting. They seem to be no longer available (and rare secondhand, and maybe also deteriorated )?. Therefore as it does not appear to crop up as a common problem, my fingers also crossed. Dave Link to comment Share on other sites More sharing options...
PeteH Posted March 4, 2018 Report Share Posted March 4, 2018 Hi In the deepest darkest recesses of my mind, have I not seen somewhere where Fixing/locking the two parts together is/was a partial solution, albeit not a satisfactory one from the point of view of actual vibration damping.? Link to comment Share on other sites More sharing options...
JohnD Posted March 4, 2018 Author Report Share Posted March 4, 2018 Locking the two parts would make it a pulley, not a damper pulley! John Link to comment Share on other sites More sharing options...
daverclasper Posted June 1, 2018 Report Share Posted June 1, 2018 If the 2 parts of the pulley are still bonded and not slipping, the rubber, though intact, could be hard with age and not damping enough?. Dave Link to comment Share on other sites More sharing options...
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