Originally Posted By teknome
Originally Posted By Rog
What does resonance feel like? Can you feel it through the car and steering wheel or just the engine?


The resonance is similar to a problem I had on another Morgan where the inside of the tail pipe rattled at a certain engine speed. In this case there is a something resonating in the engine bay around 2,500 rpm. It disappears above and below that speed. Occurs when car is moving or stationary. So its just an annoying noise.

Everything is screwed down where it should be, and I have gradually improved on the MMC layout and moved bits apart where they touch (but shouldn't).

I did disconnect the vac pipe to what may be the swirl flaps but that made no difference.

I had a slight resonance at 2600rpm both stationary and moving. Took me a while to track it down and initially thought it was coming from the engine. Everything was tight as you say but did find changing the vertical adjustment on the exhaust changed it.

Eventually tracked it down to the exhaust silencer box. Having stripped the box out to check the baffles were not loose I discovered the car was originally fitted with a MEX 1107 through exhaust (you would have not known as it wasn’t particularly noisy). I changed the box to a MEX 1105 and it instantly fixed the problem. Nice and smooth since without that annoying resonance.

Worth getting down and checking the little metal plate with the number on. See pic below.

Roger
2011 Plus 4