I was taught to always remove a ridge whenever pistons are going to be removed. I've seen fellows try to knock pistons out the top side and break rings...even saw a man once wedge a tiny piece of broken ring, keep trying and mess up an otherwise okay piston. If you can't find a reamer down your way, let me know. If you want to pay postage both ways I'll loan you mine. You may be able to find one on eBay for what the postage would cost, however. And a machine shop might loan or rent you one. Good luck.
