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Discussion Starter #1
4.530 bore
4.25 stroke
Big m block
Diamond custom pistons
.043 top ring
Diamond says setup to .007 piston to wall.
Two kits of nitrous 500-600+ worth
I ended up with one bore at .0095-.010
The rest between .007 and .008
Run it?

They had a info sheet in the box also stating
.007 (for heavy nitrous use add an additional .001-.003 for .008-.010) also stated that the .007 was a minimum spec......
Not sure why they would put this in but when called specify .007 when talking with them. What is classified as "heavy nitrous" I guess?

I see some guys setting up .009 .010 on purpose. Am I worrying over nothing?

I figured I would ask this here also since this forum section gets a little more action.
 

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A lot of this depends on piston design and skirt profile and design.
Where do they say to measure the piston?
Is this a semi round piston, full round?? Inboarded strut type??
I'd say .007 would be the absolute minimum....depending....
P.s. hope you got a heavy wall pin ...
At least .220 wall with that much hose.
 

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500 ish id set up at .008 ish, maybe a little more depending on if im doing the tune, or someone who may fuck it up........lol , and enough top ring gap to tolerate that heat. and enough pin clearance to tolerate the flex.
 

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I'd be at about .0085-.0086, no more than .009 for that combination and Line2line on the skirts. Just have them coat one piston a little extra for that o/s bore. JMO
 

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I'd be at about .0085-.0086, no more than .009 for that combination and Line2line on the skirts. Just have them coat one piston a little extra for that o/s bore. JMO
you have had luck with the line2line stuff?
I did one set for the 500,m i think the piston guy fucked up and made the piston too big under the coating, but the damn thing galled up on the dyno almost immediately and Ive been scarred to try it ever since.
 

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you have had luck with the line2line stuff?
I did one set for the 500,m i think the piston guy fucked up and made the piston too big under the coating, but the damn thing galled up on the dyno almost immediately and Ive been scarred to try it ever since.
Had excellent results, never an issue. Probably used near a dozen times now.
They have a few options as to how much they will apply. It's based on a percentage of bore clearance. The ultimate is to apply enough to where you have to hand fit the pistons. They want them tight enough to not slip though the bore but you can push through with a finger. If that's the case, there is a very specific break in procedure you have to use. I used it on a BBF I did where we had to clean up the cyls after a wash down. Bores were about .0015 over what I wanted and instead of buying new pistons, Ed @ Total Seal told me about Line2line. Saved my bacon. 611" engine went on to make excellent power, ran 8800-9000 on the track. Been using it ever since. You can get them to apply less material which takes a little less break in. I usually get about 40% of bore clearance now on our street stuff. Doesn't require a break in. They tell me they've figured that's about where it stops wearing on most apps. Hope that helps.
 

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Had excellent results, never an issue. Probably used near a dozen times now.
They have a few options as to how much they will apply. It's based on a percentage of bore clearance. The ultimate is to apply enough to where you have to hand fit the pistons. They want them tight enough to not slip though the bore but you can push through with a finger. If that's the case, there is a very specific break in procedure you have to use. I used it on a BBF I did where we had to clean up the cyls after a wash down. Bores were about .0015 over what I wanted and instead of buying new pistons, Ed @ Total Seal told me about Line2line. Saved my bacon. 611" engine went on to make excellent power, ran 8800-9000 on the track. Been using it ever since. You can get them to apply less material which takes a little less break in. I usually get about 40% of bore clearance now on our street stuff. Doesn't require a break in. They tell me they've figured that's about where it stops wearing on most apps. Hope that helps.
i may have to try it. It sounds good in theory, as it should wear in to the exact shape the motor wants. I just had a negative experience, so im skeert...lol
 

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Had Brain Neal at L2L in SC add .002” per skirt (.004 total) to a set of billet pistons that I ran at .0065” P to W previously. Had a slight clean up hone done to the cylinders, put the same rings back in, picked up .5” vacuum through the rpm range with no other changes to the short block.
 

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you have had luck with the line2line stuff?
I did one set for the 500,m i think the piston guy fucked up and made the piston too big under the coating, but the damn thing galled up on the dyno almost immediately and Ive been scarred to try it ever since.
Had the same thing happen. Was probably more tune up / top ring gap in my case but have been scared since.

Pistons will grow alot, I would be somewhere around .010 in this app, but thats just me. Not worth chasing it IMO
 

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My thought if i try it again. If i think i want .008 im going to grind the piston for .014 or so naked, and have them coated so it should settle in where it wants, with coating still on the piston. I never stripped the coating off, the piston guy wanted them and i heard nothing back....lol. But ill bet my ballsack he ground them big, and thats what lead to the very rapid failure.
 

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My thought if i try it again. If i think i want .008 im going to grind the piston for .014 or so naked, and have them coated so it should settle in where it wants, with coating still on the piston. I never stripped the coating off, the piston guy wanted them and i heard nothing back....lol. But ill bet my ballsack he ground them big, and thats what lead to the very rapid failure.
I would talk to them before you make any decisions on clearance. If you want .008, I'd grind the pistons for .008 and let the coating do what it does but again, I'd talk to them. JMO
 

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okay cheers, got it. How long were you leaving the engine between heat cycles?
Honestly I don't remember as far as actual time. However long it takes for it to cool off enough. Kind of a judgement call.
 
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