Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Clanking Sound

Thanks everyone for your suggestions. Note that the clanking sounds only occurs when the engine is in gear. I have been taking it out of gear and avoiding downshifts to eliminate the sound. Makes me think it's not the belt.

taking it out of gear and, in effect coasting, does not mean that it is not the belt. The belt "slaps" when there is reverse pull against it. being out of gear eliminates the reverse pull.

Think of it this way.... going forward at speed the top of the belt is pulling the wheel/sprocket. When you decelerate the wheel/sprocket is now pulling the engine through the bottom of the belt.

What year is your car? Does it have the Centa compensator, or is it a pre 2014 car with the original Harley style compensator.

When my M3W came back from its re-manufacture at Malvern last year, I was amazed how tight the belt was. I was checking as they had not bothered to pump up the tyres, I wondered if they had tightened the belt properly. Like a rod of iron is how I would describe it, with maybe less than 1/4" of deflection possible. Considerably tighter than I would have made it before, anyway. My M3W has always clanked at low speed over a rough road both with original chassis' rigid mounted BB and now NVH bushed BB. I found it is quite sensitive on this to rear tyre pressure. Even slightly above 25 psi and the clanking increases a lot.

Wilson

It's a 2017...

I had same experience. When car came back from the factory last year after the chassis upgrade the belt was very tight. I released it to my normal tension. This year I also got a clonking sound from below. Checked everything where it could be come from. I tensioned the belt much tighter ( too tight to my opinion ) and the clonking sound was gone. But I feel a bit uncomfortable with such a tight belt.
I have no NVH installed.

Laurens did you have a replacement chassis? My cracked 2013 one replace & it now has the NVH kit but not originally.

Still have the original chassis without NVH

So it turns out that the clanking sounds was the belt rubbing up against the mudguard when downshifting. Not sure why depressing the clutch made it go away. Anyway, I considered tightening the belt but everything seemed fine so I ended up removing the mudguard, bending it a bit and bolting back on. No more issues.

I cut a notch in the mudguard.