59A oil leak from behind flywheel

[pooch]

Got reco engine running and it was OK for a bit...65 pounds oil pressure.

Then it suddenly is pouring oil out from behind flywheel.

Pulling engine today.

I misplaced the original grub screw at the end of oil gallery, and made up a grub screw to fit.

I have since found the original and it looks to be a bit tapered to seal better.

My grub screw was a piece of cut bolt so it was straight and although I put sealer on it , it must be the culprit.

I am guessing I will find the screw has leaked pressurised oil and blown the cover gasket out .

It was too sudden and too much oil for anything to do with the main rear seal I think.

What is the general consensus?