Piston slap or lifter noise on cold startup
09-26-2012, 06:46 PM
#21
If it starts and goes away it is piston slap, if it starts and gets seemingly worse it is more than likely lifters. Neither will leave you stranded at first sign but should be addressed. The LS1 with the common "piston slap" issues are very over sized when originally built. We have been measuring them for a few years and on a rebuild most come apart .004-.006" over in spots. That is a BIG #. you get a lot of piston rock until you get some heat in it. I wouldn't loose sleep over it if it has just started but start looking into a permanent fix before it becomes a problem that can not be resolved with an oversized piston or basic short block.
02-06-2014, 10:16 PM
#22
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Piston Slap vs Valve-train noise If it starts and goes away it is piston slap, if it starts and gets seemingly worse it is more than likely lifters. Neither will leave you stranded at first sign but should be addressed. The LS1 with the common "piston slap" issues are very over sized when originally built. We have been measuring them for a few years and on a rebuild most come apart .004-.006" over in spots. That is a BIG #. you get a lot of piston rock until you get some heat in it. I wouldn't loose sleep over it if it has just started but start looking into a permanent fix before it becomes a problem that can not be resolved with an oversized piston or basic short block.
I think you mean it is undersized. Oversized would mean that the piston is larger than stock.
Either way, the problem on some of these that is causing the slap is the short skirts pistons. Not sure about the LS1 motor but many of the HP motors have short piston skirts that will allow the piston to rock more. Since the motor is cold, the piston is smaller then. The rock is more pronounced as thompson said already and therefore will slap the sleeve. There are some companies that will coat your piston that help prevent wear and will help fill more area on the skirt to help with this.
It is not cheap but not too bad. It would help.
10-25-2014, 09:43 PM
#23
Hi all,
Ive got this cold start noise and Im trying to determine if its piston slap or lifters. I know its hard to diagnose over a audio file, although I might get some ideas.
Seems to be more apparent now its alot colder at night.
Ive run Penrite HPR10 and Castrol Magnatec both resulting in similar noises at a cold startup.
The noise practically goes away after about 3-5 minutes.
http://www.youtube.com/watch?v=Kcicg0xnLcs
Ive got this cold start noise and Im trying to determine if its piston slap or lifters. I know its hard to diagnose over a audio file, although I might get some ideas.
Seems to be more apparent now its alot colder at night.
Ive run Penrite HPR10 and Castrol Magnatec both resulting in similar noises at a cold startup.
The noise practically goes away after about 3-5 minutes.
http://www.youtube.com/watch?v=Kcicg0xnLcs
02-12-2016, 06:21 AM
#25
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I have experimented with this problem for years on my truck I bought new. It started about around 5k miles. The Dealership was no help. " it is normal for it to make this sound".
But as I have built from scratch Chevy engines I know that this is not true.
And with the "knock" worse on start up in the morning, I believe it to be that the lifters are bleeding down over night, and after a while running and driving, the noise goes away.
If it were a piston problem, bearing etc. the noise would not go away. I have a good results with adding a oil " stabilizer" with a 10-40 oil. But I am going to change the lifters with non-bleed down lifters.
I will post the results soon. After I find the right lifters etc.
keep tuned.
02-12-2016, 10:00 AM
#26
Bro... This thread started in 2012... And died. Then was resurrected in 2014... And died again. Let the poor ****er rest lol.
If you need to ask a question or discuss something about your car, start a new thread. Don't post in old ones.
As for piston slap, this has been beat to death. If it goes away when warm, likely not an issue.
If you think its a lifter issue, check the oil pump pickup o ring. As these cars age the o ring cracks/tears and allows air into the oil, this causes a noisy lifter and/or valve tick.
If you need to ask a question or discuss something about your car, start a new thread. Don't post in old ones.
As for piston slap, this has been beat to death. If it goes away when warm, likely not an issue.
If you think its a lifter issue, check the oil pump pickup o ring. As these cars age the o ring cracks/tears and allows air into the oil, this causes a noisy lifter and/or valve tick.
02-12-2016, 12:31 PM
#28
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Piston slap was a common LS1 issue in 2012, and 2014, and even 2002. It still accounts for many of the cold-start noises that people hear today. Contrary to some of the posts in this thread, you don't have to do anything to "correct" this, assuming it's piston slap, the engine will run just fine for a normal lifespan even with the cold start slap. My '02 was just a few years old when I bought it, and it did this every day from then until 2014 when I sold it with ~110k miles. It ran just fine and the problem never got any better or worse.
02-14-2016, 09:29 PM
#29
Piston slap was a common LS1 issue in 2012, and 2014, and even 2002. It still accounts for many of the cold-start noises that people hear today. Contrary to some of the posts in this thread, you don't have to do anything to "correct" this, assuming it's piston slap, the engine will run just fine for a normal lifespan even with the cold start slap. My '02 was just a few years old when I bought it, and it did this every day from then until 2014 when I sold it with ~110k miles. It ran just fine and the problem never got any better or worse.
