A friend of mine has an 1992 zr 580 and he rebuilt the engine using wiseco's. The first season one of the pistons flaked apart under the rings. Wiseco paid for new pistons and new cylinders. Two years later on his new set the pin for the ring (end gap) has started to back out. Causing minor cylinder damage. has anyone had this problem before? I was thinking of using wiseco's on my engine rebuild but now i'm not sure. I thought wiseco's were so good?

opps it's a 93 not a 92.

Maybe pistons to cylinder wall clearance where not good. Or not enough warm-up time cause early failure.

Both ring and piston clearance were close to the tight side but well within specs. As far as warm ups he has a temp gauge and we both will let the pack go and (catch-up) when we are warm. Wiseco is covering the bill I would just like to know why they failed? The sled is stock other then clutch (spins @ 8,200).

Friend of mine went through the same thing on a 94 zr 580. Seems like the pin would move or something and the ring would twist and get caught in a port and
tear it up. I also had the same problem with Wiseco in a triple Polaris. It happened a few times. They always backed there product and did the machine work as well. I just got tired of all the down time. My buddy with the ZR went back to stock pistons and never had another problem. ;)

We had the same problem with Cat pistons on a 95 ZR580... ring spun... new jug!! :angry:

I have used wisecos in my rebuilds, all worked good, I think you had a bad bunch.

Yeap JUNK. Thats all I have to say about them. Thats what they are famous for I cannot believe they are still in business.

I have to agree with xc600 100%. Nothing but problems with there product for me over the last 5 years. Even after they would tell me the design was changed I would get the same results. They are junk in my opinion. Only thing I will say is that the customer service was great. ;) :withstupid:

someone help me-wisco pistons are either cast or forged-and one of these the piston heats up different-i had wiscow piston skirts crack in phaser 440s with my 94-zr580 torched 2 pistons do to incorect jetting but replaced with oem and never had problems.i think when zrs waste cylinders it is do to coolent temp-not egt :hallo1: