I have a gsr block with 100,000 miles and my rings are starting to go out? so i was gonna add some Type R pistons , but should i put some standard bore or should i get oversized? Right now i got a good deal on some brand new JDM ITR Standard size bore pistons? Should i go with those or get oversized? any help would be appreciated.

 

always clean the bore out with a small hone after disassembling the bottom end, especially with that kind of mileage.

 

In my experience I would recommend going to the oversized piston. So you can get a proper hone job on the bores. The finish of the bores dictates the quality of the ring seal. With the mileage you have on the motor by the time you get a good finish on the bores your piston to wall clearance will be to large for an 81 mm piston..

 

It really depends on how the measurements come out. If any one of them is beyond the service limit, or getting close to surpassing the limit, then overboring is recommended.