hi, when i reach 50ish MPH in my MK Indy and lift off the accelerator there is a lot of vibration. Is stops at 45ish MPH. Everything is tight and there are no loose bolts.
Has anyone any ideas of what could cause this?

welcome to the mad house !

it could be play in the cantre bearing of the propshaft?
im sure someone will be along soon with some more ideas

what you want to do is fit a propper (car) engine, no problems then

And welcome

could be harmoics

What do you mean by harmonics?

The vibration is quite heavy. I have just installed a new engine after blowing the last one up.

might be worth popping this question in the BEC section
or a link to this thread in there

It does sound like propshaft inbalance, jack the rear wheels off the ground and block the car solidly then run it up to 45mph and see if the prop is shaking.

If so try popping a jubile clip on the prop, it will act like a balance weight if it makes it worse then you have identified the issue, you may find an optimum position where it sorts everything out.

Regards Mark

could you have failed to tighten something up properly in the swapsy?

did it do it before engine change, If not I would think prop adapter to engine or adapter to prop area

tony

[Edited on 1/8/09 by mad-butcher]

last time I heard this we were on the way to stoneleigh.........and a lads propshaft center bolt jumped out.
Not wanting to spoil the last few miles to the show we cabletied the prop together and he drove it to the show