Wiseco F*** Up!?

[02ss]

Alright so I get my pipes in today, get em on, fire it up, starts first kick, yeah I got a big ass smile now. Then I run it up a short path a couple times, bring it back and there's a tinging that isn't normal, really thought it was a bearing to start with. So then I tear the topend back off and one piston is gauled up on the intake side, wtf!? So then I notice this piston has more clearence then it should, break out my calipers and the piston is .009" undersize, these are 65mm pistons that came in a topend kit, the good one measures 2.556 which is right and evidently this is the one I used to check my clearence when I honed the cylinders. Nope I didn't measure the other piston like a dumbass before I put it on but it measures 2.547 at the bottom of the piston on the good surfaces, it doesn't have any taper from the rings down like it should have and I guess that little extra rocking got it snagged on the intake ports and gauled it up. Has anybody else ran into this problem and do you think wiseco will send me another piston since they sent out a bad one.

[blowit]

Alright so I get my pipes in today, get em on, fire it up, starts first kick, yeah I got a big ass smile now. Then I run it up a short path a couple times, bring it back and there's a tinging that isn't normal, really thought it was a bearing to start with. So then I tear the topend back off and one piston is gauled up on the intake side, wtf!? So then I notice this piston has more clearence then it should, break out my calipers and the piston is .009" undersize, these are 65mm pistons that came in a topend kit, the good one measures 2.556 which is right and evidently this is the one I used to check my clearence when I honed the cylinders. Nope I didn't measure the other piston like a dumbass before I put it on but it measures 2.547 at the bottom of the piston on the good surfaces, it doesn't have any taper from the rings down like it should have and I guess that little extra rocking got it snagged on the intake ports and gauled it up. Has anybody else ran into this problem and do you think wiseco will send me another piston since they sent out a bad one.

 

 

If it is truly a bad apple, they will probably cover it but they should be checked before using. I would not trust your bottom of skirt measurement now that it has been run and damaged. The skirt may be bent. I also would not rely on a caliper to measure the piston. We generally see the Wiseco pistons hold .0002 in tolerance.

 

 

Brandon

[bk_banshee]

I haven't seen a set of pistons that are the same size. There is always some difference. I bet .009 is within Wiseco's tolerance range but might want to still check with them.

 

Now you'll always hone to the piston size from now on though.

[blowit]

I haven't seen a set of pistons that are the same size. There is always some difference. I bet .009 is within Wiseco's tolerance range but might want to still check with them.

 

Now you'll always hone to the piston size from now on though.

 

 

 

.009 is a mile for a piston tolerance. I agree that there is something wrong. Possible even the wrong stamp on the piston. IE, it might be a 64.75mm piston. If it has not crown expansion relief, something is odd.

 

 

Brandon

[woodwardspecialties]

we always machine the cylinders to match the piston.... you definatly need to check them both before install...

[racer]

we always machine the cylinders to match the piston.... you definatly need to check them both before install...

That's how mine have always been done.

 

I'm with blowit on this one. As a machinist, .009 is a long frickin way. A tight fit, not interference fit, for that size should be within .0005 if I remember correctly.