I had great success using the heat gun on two new non-ringed engines.
Heating the top end takes away the pinch at start-up, and does away with
the stress the rod has to endure....not to mention jamming the piston into
a too tight bore....and then yanking it back out. [X(]

I also oiled the tops of the engines. Try the heat gun on those really tight
new engines....

Dave.