Vibration under hard acceleration

[Escort2dr]

Need a bit of help with my Mk2 Escort please...

Under hard acceleration, the whole car seems to vibrate noticably (and audibly) and I can't seem to trace the source; it is on a replacement s/hand engine as the other was worn, a brand new single-piece propshaft for the second time, and the diff and one of the halfshafts were replaced some time ago with s/hand ones. The prop is lined up properly and has a brand new gearbox mounting rubber. The only things not replaced are the other driveshaft, and the engine mountings.

There was worse vibration before but this was much reduced by changing the prop and getting everything lined up. The vibration only now seems to occur when accelerating hard.

I'm totally lost as to what the cause might be - any suggestions would be gratefully received and investigated.

Thanks.

[Auntieroll]

I had a similar problem with a Dolomite Sprint many years ago,when accelerating hard the nose of the diff was kicking up due to the torque acting on the axle,which put the CV joint in the propshaft under excessive angularity,hence the awful noise,cured it with ST bushes in the rear upper arms which prevented the axle twisting up as much.Also saved a small fortune in propshafts!!

The Ford has a different rear axle mounting IIRC cart springs,but its possible that a similar thing is occuring ,surely someone must have had a similar problem when putting powerful engines in Escorts,I doubt theres a shortage of Escort knowledge out there!

[Escort2dr]

Thanks; the axle is the standard English and I had anti-tramp bars fitted ages ago to keep it in situ though I am sure it could still twist on the springs.

When I get chance (and my back allows) I might just recheck all the angles for the prop. It doesn't seem to do it all the time, which makes it stranger still.

[Zad]

How are the engine mounts? I'm thinking maybe that under load the engine is moving around, putting the prop shaft etc out of alignment.

[Escort2dr]

Will need to check them but now hampered by a seriously knackered back. Someone on another forum said to check for contact marks on the sump, which I do seem to remember is very near to the crossmember.