I have made quite a few swerves and u turns in my efforts to sort out the drive train and so here is a concise, not necessarily chronological, account of my research, modifications and findings.
My machine is a 2013 model with Centa drive coupling and NVH kit fitted before I purchased it in 2015 with 625 miles on the clock from new.
The problems to be cured were the need to rev the engine hard on pulling away to avoid clattering and banging and the loud bangs and jerking when accelerating hard. Also addressed were the fierce vibrations at 3,000 rpm in higher gears.
I firstly replaced the final toothed belt drive with a chain. This had benefits in reduced cost to replace, simplicity of changing the overall gearing and quieter running. This did not, however, cure any of the problems mentioned above.
I replaced the barrel shaped rollers in the Centa drive coupling with polyurethane blocks made to fit precisely in the recesses in both rotors. This cured the pulling away issues but not the big bangs on acceleration. These blocks have subsequently been modified in shape to give a little more shock cushioning but still not the free play found when using the originals. After 1,600 miles of hard test driving there were absolutely no signs of deterioration of either the inserts or the surfaces of either rotor.
I fitted a front bearing to the shaft which supports the Centa coupling and clutch as I thought this would improve the life of the single standard bearing and help with vibration damping. This has probably only brought about minor improvements to the vibration but I still think it worthwhile for the longevity of the set up.
Much of the vibration stemmed from the so called NVH kit. The front of the bevel box was found to lift and therefore transmit vibration through the final drive to the rear wheel. I discarded the NVH kit and re mounted the bevel box directly to the chassis using clamps with 2.5 mm. thick polyurethane liners to isolate the high frequency whine from the bevel box ( this was presumably the purpose of the NVH kit ). I made and fitted a third mount extending up to the cross member behind the seat backs. This has eliminated all serious vibration problems. The bevel box still whines but I do not think that is an issue which can be resolved by external modifications. The surprise is that this has also completely eliminated the banging on hard acceleration. I confess to not knowing why but I think the front of the bevel box lifted to a greater degree than I had managed to observe and then would snap back down on to the chassis with a bang and resultant hard jerk to the final drive.
Prolonged road testing has proved the entire system to be safe, reliable more comfortable and the vehicle more pleasing to drive.
To read my reports on the whole process including pictures please go to
www.bleazey.co.uk and click on the picture of my Morgan.
If there is interest, I would be prepared to make a preliminary, small batch of kits to include new polyurethane coupling inserts, the bearing and stub shaft for the front end of the coupling and a full set of bevel box mounts. The chain final drive is not something I think the average owner needs to worry about, a new steel rear sprocket seems to be the answer to early failure. I would endeavour to supply instructions for the entire installation procedure from start to finish for people to follow themselves or to pass to their chosen garage mechanic. Do, please, let me know your thoughts on this.
All the best,
Phil
