Tango,
What type of pistons are they ? I have found lately that there is quite a variation in pin sizes from manufacturer to maufacturer and a lot of them are coming in a lot tighter in the piston than I like to see for sure. I like to see at least .0007" - .001" on performance engines. I guess they are press fit from your description. What I do is similar to what gtrdone said. When I install the pistons using the rod heater, I wait about ten minutes to let them cool off a little and then I squirt some assembly lube on the pin and it wicks in like soldering a pipe. I have never had an issue doing it this way.

I bet once your guy removes the pistons from the rods he will find some hot spots on the pins.

Personally I think that a lot of unexplained rod bearing failures are from pins geting tight and not allowing the rods to pivot freely.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

I assume you're not re-using the rings?

Take your rings and pull them apart. They should crack in half pretty easily. If then bend and don't break the cylinders saw a ton of heat.

Thanks again for all of the great input. As far as detonation, it is an efi motor with a knock sensor that is supposed to send a signal back through the MEFI-3 to make adjustments.

I am no engine builder, but are guilty of researching things to death. seems to me that the initial clearances/lubrication of the wrist pins may have been the culprit.

With any luck, we will be putting itback in on Saturday and getting it out onto a local lake. leaving with it on Sunday for lake of the Ozarks for the Midestboatparty.com Support our Troops Poker Run.

I'm No builder But......
 

I just went through the same issue. Unfortunatly, I lost the whole unit, block and all. My EX- Marina rebuilt due to a cam lobe, and when they installed the new build, the oil line was pinched a bit and destroyed the new cam, mains, crank, and a couple of rod bearings. Oh yea, and the tainted oil did kill the pins also. Do yourself a favor and take a real close look at the piston skirts for any signs that metal be driven into them.
Best of luck and I feel your pain. Mine pain was 9K worth of learning the lesson that when you want somthing done right,,,Do it yourself!