Third piston since september

[joedirt5724]

My blasty blew up again for the 3rd time since September. It broke the damn intake skirt right off the piston.

The first time it blew up it broke a ring, cause they spun and caught a port.
The second time was 2 days after the fresh top end was installed. The company i had bore my cylinder bored to tight to the motor instantly seized. And now im not really sure why it broke again???
Oh and the piston seams to be greasy.

 

[MINIGfather]

Damn bro that sucks...

 

[brandoz28]

piston looks like detonation. what fuel are you running?

 

[super noober]

it was probally a sh*tty bore job and you had extreme piston slap causeing the skirt to break. thats nasty stuff man..

 

[joedirt5724]

I run 93 octane highest i can get at the pump, and amsoil dominator racing oil. And after the second blow up i had the cylinder honed by a good friend thats big into lake racing with sleds and had him hone the cylinder for me and i could see my reflection on it.

 

[brandoz28]

what kind of piston is that

 

[speedracinshift]

what type of pistion are u running

 

[stephen12091985]

damn thats sucks.is your jetting right?

 

[joedirt5724]

wiesco .40 over

 

[joedirt5724]

havent touched jetting since last rebuild, plug was a nice dark pancake brown

 

[speedracinshift]

do u let it warm up good

 

[joedirt5724]

had been rideing for an hour before i noticed a different pitch in the exhaust sound, shut it off and pulled it home.

 

[brandoz28]

did you check piston to wall clearance?

 

[yb200]

did you check piston to wall clearance?

thats what im thinking to much clearance

 

[phragle]

Well..to start with, you will NOT see your reflection in a good hone job. a good hone job will reveal a dull looking cross hatch pattern. This throws into question the sizing/clearance of your bore/hone job. Is that piston a wiseco?? probably not, they dont usually come apart. A cylinder is bored slightly undersized, then honed to proper clearances. Unless he had full length stones and a micrometer there is no telling whether it was tapered or out of round. were the ports chamfered?

 

[joedirt5724]

thats all i run in any engine ive rebuilt, weisco. ive got the box to prove it.

 

[brandoz28]

that piston doesn't look like my wiseco at all. that one looks cast

 

[yb200]

that piston doesn't look like my wiseco at all. that one looks cast

i was thinking that to the wisecos have the # stamped in the center on the top of the piston that ones doesnt

 

[super noober]

Well..to start with, you will NOT see your reflection in a good hone job. a good hone job will reveal a dull looking cross hatch pattern. This throws into question the sizing/clearance of your bore/hone job. Is that piston a wiseco?? probably not, they dont usually come apart.

i was thinking that too with the crosshatching, last time i got a fresh bore back it was dull and kinda rough

 

[yb200]

i was thinking that too with the crosshatching, last time i got a fresh bore back it was dull and kinda rough

yup thats the way it should be