LLY: How much can a stock bottom end LLY take?

malibu795

malibu795

misspeelleerr
Apr 28, 2007
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DMAXchris said:
I cant believe it took 22 posts to ask this question.
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i saw it while back.. thought why would he put head/main studs w/o at leat a hone job on each group.. i can buy the head studs w/o hone job, but main studs will bind the crank once torqued to spec... figured they where in a pile waiting to get isntalled.. then he cleared that up...

i know head studs will flex the cylinder walls some .002-.003" with current tq specs... someone(johnboy?) mention that there was no wall flex when ARP gave there first tq spec of 90lbft?

pretty sure stock main clearance is .0020-.0035.. i havent heard how much main studs will distort the main bearing bore
 
J

jkholder09

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Jan 8, 2012
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paint94979 said:
Timing... Really? I've run as much as 38* at 3600 rpm. My engines still running well. You should stop regurgitating what you have read on the internet.

OP if you're tuning it you are going to want to tune out as much torque as possible. In my experience a detorqued tune and sensible street driving is feel comfortable pushing it to 650hp but anymore than that is going to be a gamble
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SSchmi5519 said:
Lots of worn out LB7 pump trucks prove otherwise.
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With bad tuning they just don't last.
I don't think anyone with any sense here would say 38 degrees of timing is a safe level.
I would suggest limiting maximum timing to 30 degrees just to be cautious.
 
SSchmi5519

SSchmi5519

LLY Cult Leader
Oct 19, 2008
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jkholder09 said:
With bad tuning they just don't last.
I don't think anyone with any sense here would say 38 degrees of timing is a safe level.
I would suggest limiting maximum timing to 30 degrees just to be cautious.
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If you don't know the pulse how do you know 38* is too high? oh that's right you don't.

Go ahead and limit to a flat 30, have fun melting pistons. :rolleyes:
 
J

jkholder09

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Jan 8, 2012
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SSchmi5519 said:
Go ahead and limit to a flat 30, have fun melting pistons. :rolleyes:
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I have never melted a piston in an lb7/lly and won't.
And it would be more likely that they crack with big pw before they melt.
He said lb7/lly not lbz/lmm steve.:roflmao:

To the op:
To help keep you safe I would recomend staying below 3000 pulse and 30 degrees of timing.
 
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paint94979

paint94979

Beer Nazi
Sep 18, 2006
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jkholder09 said:
I have never melted a piston and won't.
And it would be more likely that they crack with big pw before they melt.
He said lb7/lly not lbz/lmm steve.:roflmao:

To the op:
To help keep you safe I would recomend staying below 3000 pulse and 30 degrees of timing.
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So I've ran 3300 pw since 2007 ranging from 34-38* timing above 3200 rpm running 12.3's all the way down to 11.8... I've got roughly 350 1/4 passes on it with many dyno pulls and dicking around on the street. Timing and big pw does not kill LB7 and LLY pistons in my experience.
 
TheBac

TheBac

Why do I keep doing this?
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Apr 19, 2008
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Don't take this wrong, but just because something works on one truck doesn't mean it'll work or be safe on another. In this case, I have to agree with Holder. Keep pulse and timing reasonable (3100us/28*) and the engine should be ok
 
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