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Thread: Noisy forged Pistons??

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2011-03-22 05:13:35
Noisy forged Pistons??
K so I just put the new motor in my car that was built with Weisco 9.0:1 Pistons. Its been ran before for a lil bit. But not very long. Is it normal for them to be noisy on first start up after sitting for a good while?

Motor runs perfectly, revs up fine, and started up on the first try btw. The noise doesnt follow the revs so its not rod knock.
2011-03-22 05:54:06
ive heard of pistons being cut wrong and hitting the squirters... you might want to check that
2011-03-22 06:02:18
From looking around its normal before they warm up to be noisy. I didnt get to run the motor long since my neighbor came over and told me to shut my loud shit off lol. I didnt realize what time it was! The motor runs perfect. I just couldnt let it warm up cause I have a lil coolant leak on the back of the block where I forgot to put sealant on the coolant temp housing. Im excited to drive it tom!
2011-03-22 06:14:51
Not usually noisy. I just got done putting together an S14 motor that I fully built for a buddy, eagle rods, JE pistons, ACL bearings, Cosworth headgasket, block was freshly bored and honed to the final bore of 86.5mm. Pistons are 8.5:1 and the thing started within the 2nd revolution of the crank on the first try and was quiet as a mouse. After fixing a massive coolant leak on a hose under the manifold I let it warm up and all was good.

Did a couple other cold startups on it and the only noise was the timing chain rattling for a second because he is using the old style tensioner.

You sure its not lifter noise or any of that.
2011-03-22 06:32:30
Took the valve cover off just to make sure it wasnt from there. But everythings good. Ill see tommorow if it goes away like it should. Cant really do anything tonight. Oh well
2011-03-22 06:32:54
double post
Last edited by Johnny wangwang on 2011-03-22 at 06-37-12.
2011-03-22 23:22:20
It sounds lke its coming from the timing chain tensioner. But im not sure. It seems loudest in that area though. Im gonna swap it out and see what happens. Im gonna need to drive on it for a lil bit though. Its not gonna kill anything is it to drive on it for a lil?

Cars runs great though ! Now I just gotta tune it with the SAFC and Ill be good! Now its on to working on this stupid Vette!
2011-03-22 23:24:59
Is it a constant sound? Does it speed up as the revs increase?

Guess I should say that yes, forged slugs can be a bit more noisy than their cast counterparts.

Get a video.
Last edited by Cliff on 2011-03-22 at 23-28-00.
2011-03-22 23:31:59
I dont really have any way to Video it. Its wierd though. It only happens from like 2500-3000rpm now. I got under the car and you can clearly hear the pistons. But when you get close to the head you can hear it the loudest. Obviously its either the pistons or the Tensioner. But From my research forged pistons in SR's normally make a little clacking at certain rpms depending on the tolenrances of the piston to cylinder. So....I guess its time to pull out a stethescope! I fixed the coolant leak and now im leak free knock on wood. So this is the only other issue.
2011-03-22 23:57:52
you often hear things about forged pistons being noisy and smokey on cold start up cos of the bigger clearances and higher thermal expansion of them, however i think it's a bit of a myth that its ok/normal tbh. My ve has forgies in and isn't noisy or anything, i was careful to get the clearances all spot on. just my 2p

hopefully it's not that and like you say it's something tensioner/top end related. chain rattle etc
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