I have 3 irvine 40 diesels (from irvine as diesels not conversions)
rugged good runners) they do have the tendency to drop their
contra pistons on occasion out of the head..very very worthwhile
to update with new heads (NOT AN IRVINE ORIGINAL) since it
can happen again \\\\Davis diesel makes one for this engine////
One of mine did the big drop so I changed it and and updated
the other 2 also .

Its easier to just pop the contra piston out and give it a good whack with a hammer. I've done this with various diesels and it works fine!

Max