Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Centa question

Hello,

Drove the other day in 30°C heat and slow pace with traffic. The engine behaved fine but at a certain point got a lot of unusual vibration in the transmission. This did go away when driving later in lesser heat. Could this be the rubber wedges of the Centa heating up too much and not working as they should and therefore giving vibrations through? Do people with new quality wedges feel any difference to the initial model?

Hi Nadvys,

I don't think the Centa coupling causes vibration. Symptoms from the Centa are jerking and banging if you pull away with the revs too low and a soft lumpy feeling as you pull away when the inserts are about to break up. High temperature is a likely cause of failure in the earlier ones.

Vibration is most likely to come from the NVH kit which allows the front of the bevel box to climb upwards as you accelerate, this becomes a quite violent up and down vibration at certain revs. Most usually as you accelerate through 3000 rpm. Quite why it went away at lower temperatures I don't know.

Good luck,
Phil

This could also be a symptom of the S&S skip-fire mode kicking in when the engine overheats. At idle it increases the vibration and shaking but it will disengage after you've hit 5mph.

It is unnerving when encountered for the first time!

No NVH kit on my 2012 model and skipfire i had already so can recognise it

Hmmm. Removing the NVH kit usually stops the vibration so what next?

My machine is fitted with a chain final drive and if the chain is slack it will snake when running slow and no load - can this happen with the belt drive? It might be worth experimenting with belt tension.

It may be worth checking the flange bolts on the hardy spicer joints in the prop shaft but I can't see that problem going away on its own.

Did you dip and re-engage the clutch while it was happening? If so did it make a difference? A friction plate breaking up perhaps?

I am clutching a straws for an answer here so I think you may have to do the old trick of letting it develop - but carefully!
Again - good luck.

Thanks Phil, i'll check the clutch next time. I'll also check the BBox oil and maybe change to mineral 140 (i have a leak at the nose end)

Sometimes pieces of rubber get stuck between the crankcase and the centa when idling or braking to stop, this leaves black marks visible from underneath the steering rack.