787 piston question

[MEDOO]

Ok, so I'm putting my topend back together. My helper snapped the lower piston ring on one of the pistons while putting the jug on. So I'm ordering a new set of rings. I'm measuring piston diameter just below the broken lower ring. Its measuring 82.5mm at that point. So I need rings .5mm over standard, right? I'm just making sure before I get them headed this way. What do you guys do for a ring compressor for a over bore piston?

 

[SKETSEA]

The cylinder should be at 82.5 the piston should be less

 

[racerxxx]

Does the top of the piston have any stampings?? I have an OEM first over piston I can measure up later if needed.

 

[MEDOO]

Does the top of the piston have any stampings?? I have an OEM first over piston I can measure up later if needed.

Thanks, I didn't see any stampings, but the build up on the piston would have covered it up. Its all zipped up and tarped waiting on new rings.

The engine I'm working on is white, so I think it is a rebuild. My other engine is gray or silver and matches the exhaust color etc, its probably original motor.

I measured the cylinder bore, it is +/-82.97mm and the piston is 82.5mm. So I should order 1mm over rings?