piston slap problems

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Jul 18, 2012 | 02:17 AM

#21

2baditsnotachev

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From: Minnesota

Well I pulled every piston out of the first motor and theres not so much as a scratch in those pistons let alone any cracks or crushed ring lands. They all mic out at 3.773 on the skirts to 3.750 at the top. Si what actually happened to cause them to start slapping?

Jul 18, 2012 | 06:57 AM

#22

Sarg

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From: Atlanta, GA

Hopefully getting my jy 5.3 together this weekend. I will see if I can't measure ptw and see what mine is straight from the junkyard with under 100k miles.

Jul 18, 2012 | 07:05 AM

#23

lsxmalibu

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this is how loud mine is, i know which cylinder it is because when I got the motor it had a rust spot on one cylinder, so I ran a hone through that one cylinder....it goes away about 30 sec when warm, still runs great and ill continue to run it. same as you, it just started on my motor after a 12 lb test run, woke up the next morning and slap slap slap.....its a fine line of 100's of an inch and it will slap.

Jul 18, 2012 | 10:07 AM

#24

2baditsnotachev

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From: Minnesota

Both mine are louder than that and even when warm don't fully go away just sounds like valvtrain noise when warm.

Jul 18, 2012 | 11:42 PM

#25

Fbodyjunkie06

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From: Greensboro, NC

Quote:

Originally Posted by 2baditsnotachev

Well to the guys running them for years, ill assume most of them aren't just letting them slap the whole time right? Cause I am getting alot of "that's just what they do" type comments also.

Some of them do slap a fair amount.

Jul 19, 2012 | 03:03 AM

#26

2baditsnotachev

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From: Minnesota

Well I dialed my timing back to 28 and I pull at a faster rate down to 16@20psi

Jul 20, 2012 | 01:01 AM

#27

Fbodyjunkie06

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From: Greensboro, NC

Just straight pump gas or do you use methanol injection also?

What is the AFR reading in boost?

Jul 20, 2012 | 02:07 AM

#28

2baditsnotachev

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From: Minnesota

Quote:

Originally Posted by Fbodyjunkie06

Just straight pump gas or do you use methanol injection also?

What is the AFR reading in boost?

E85 at wot its a little rich still 10.9-11.1 no meth

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Jul 20, 2012 | 11:01 PM

#29

dilsnick

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dont get pissed but what intake do you have?

my motor sounded like hell. one of the bolts holding down the intake was too long and it was slightly touching a pushrod. this caused a horrible knocking noise.

might not be your issue, but if it is its an easy fix.