D&D 900ss pistons?

[M7Plus]

I'm looking to see if anyone knows of another company who builds pistons to fit this engine. a little history of my sled is.... when it runs, it runa GREAT!... until the one ring on the piston somehow turns and peels the top off the piston. then i get to ride my wounded sled back to the truck and call it a day( side note: never had to be pulled back, my sled is as stubborn as I, we will limp before admitting defeat!) I have rebuilt this engine 6 times in four seasons and now it is collecting dust in my garage, because i refuse to put another set of F*#king wiseco pistons in it just to rebuild it again after two or three rides. any help would be great, thanks!

 

[Modman]

I'm looking to see if anyone knows of another company who builds pistons to fit this engine. a little history of my sled is.... when it runs, it runa GREAT!... until the one ring on the piston somehow turns and peels the top off the piston. then i get to ride my wounded sled back to the truck and call it a day( side note: never had to be pulled back, my sled is as stubborn as I, we will limp before admitting defeat!) I have rebuilt this engine 6 times in four seasons and now it is collecting dust in my garage, because i refuse to put another set of F*#king wiseco pistons in it just to rebuild it again after two or three rides. any help would be great, thanks!

You need to figure out why the ring is turning. It should be stationary based on the ring pin, is that coming out and the ring is turning? If so you have detonation and need more octane in your fuel. Your sig line has a NOS bottle in it, if you are pushing nos through it then you will surely need more octane likely due to detonation.

Wiseco's are a forged piston - strong but not as dimensionally stable as cast pistons. They need extra clearance because the domes expand at different rates than the skirts as they do not have the intricate webbing cast into them (because they are actually forged and not cast) like they are able to put into cast pistons. Forging makes a "tougher" piston with denser alloy, but it causes issues with the heat expansion as they do not expand uniformly. Cast pistons have much more webbing cast into them and are more dimensionally stable and will expand much more uniformly, but they are more brittle and not as dense.

If you dont have the clearances right on Wiseco's, they are a tough piston to run. If you get the right clearance and warm them up right, they will last forever.

 

[dvst8r]

A little off topic, but I need to pick up a pair of those d&d 900 pistons, can they be ordered right from wiseco, or do they need to be ordered from d&d?

 

[M7Plus]

You need to figure out why the ring is turning. It should be stationary based on the ring pin, is that coming out and the ring is turning? If so you have detonation and need more octane in your fuel. Your sig line has a NOS bottle in it, if you are pushing nos through it then you will surely need more octane likely due to detonation.

Wiseco's are a forged piston - strong but not as dimensionally stable as cast pistons. They need extra clearance because the domes expand at different rates than the skirts as they do not have the intricate webbing cast into them (because they are actually forged and not cast) like they are able to put into cast pistons. Forging makes a "tougher" piston with denser alloy, but it causes issues with the heat expansion as they do not expand uniformly. Cast pistons have much more webbing cast into them and are more dimensionally stable and will expand much more uniformly, but they are more brittle and not as dense.

If you dont have the clearances right on Wiseco's, they are a tough piston to run. If you get the right clearance and warm them up right, they will last forever.

the octane shouldnt be an issue, I only ride in B.C and while im there i pick up 93 octane fuel from chevron plus i do mix 30% VP111 race fuel in. this motor is "supposed" to be pump gas according to D&D but i run the race gas due to the happy button. on a side note the motor has never let go while on the nos but usually on the trail up or down. to the best of my knowledge the pin that keeps the rings from turning, dissapears and then the ring is able to turn and catch on a port, thus causing engine failure. I have covered all bases addressing the problems the dealer told me was causing this and it still happens. I have had the crank trued and ballanced the primary clutch ballanced crank bearings and wrist pin bearings ect..... The dealership also at one time told me wiseco had put out a bad batch of pistons... BUt REALLY, what are the odds of me getting all of them from that batch.

 

[Modman]

the octane shouldnt be an issue, I only ride in B.C and while im there i pick up 93 octane fuel from chevron plus i do mix 30% VP111 race fuel in. this motor is "supposed" to be pump gas according to D&D but i run the race gas due to the happy button. on a side note the motor has never let go while on the nos but usually on the trail up or down. to the best of my knowledge the pin that keeps the rings from turning, dissapears and then the ring is able to turn and catch on a port, thus causing engine failure. I have covered all bases addressing the problems the dealer told me was causing this and it still happens. I have had the crank trued and ballanced the primary clutch ballanced crank bearings and wrist pin bearings ect..... The dealership also at one time told me wiseco had put out a bad batch of pistons... BUt REALLY, what are the odds of me getting all of them from that batch.

If the ring pin keeps coming out the issue is very likely detonation. Timing, too lean or not enough octane on the juice. It likely will not fail on the button, since the pin has to come out and then the ring has to turn, takes some miles before that happens. The pin will come loose when you are on the button though. Check top of piston, if there are any minor signs of erosion around the outer border its likely deto. Could be minor but just enough to be happening over time.

Check symmetry on exhaust ports, one could be out of whack and putting pressure on the ring at different angles at different points in the stroke. If it has failed on either sides of the motor and not just one consistently, I would say its likely deto.