"Thunk"

[foremanbob]

Building a new motor for a mate...

Fitted new drive side bearings/seals/halite, new SIL crank with modified big end bearings.

New steel seal plate and hex bolts also used.... better safe than sorry right?

Crank turns freely in the breaing etc, but there is a quiet "thunk" that i can easily repeat back and forward at one point only in the rotation.... (piston fitted and in cylinder).... noise definately coming from bottom not top...
Mag housing fitted to centre the crank...

Had crank out and in a couple of times, cant see anything.... Any ideas.... Obviously cant leave it like this....

[Wack]

Is the big end of the rod catching the casing usually near the top n bottom rod cut outs? Marker pen the big end on the rod, refit and try again.

[foremanbob]

Found it eventually... in and out 6 times before i did though....

I need to go to specsavers... one of the screws holding the seal plate was just a "baw" hair to high and just catching