Ls1 rod knock or bad lifter?
Thread Starter
Staging Lane
Joined: Aug 2019
Posts: 97
Likes: 5
Ls1 rod knock or bad lifter? Hi, Um, I switched to full synthetic 2 days ago. I was warming up my car this morning and my brother goes out of his way to redline my car while it’s fully cold. After a short drive, I notice this sound coming out the engine... he tells me it’s a coincidence, I think he abused my cold car. Anyways, can anyone tell me if this is a rod knock or if it’s a bad lifter? Should I dump the oil and check for metals? What’s my next step... it’s a 98 Ls1 z28 with 93k miles. 6 speed :/ I also need to add that this video is taken at a fresh cold start and you can hear the noise get quieter after the first rev. I understand rod knock only gets louder as the car warms up so that’s why I’m thinking it’s a lifter?
Last edited by Bakir Bakir; Feb 5, 2021 at 10:32 PM.
That is how mine sounded when my lifter destroyed my ls1. Don't start it anymore, drain the oil and see what if any debris comes out. Pull the head remove the lifters. Pray the lifter just collapsed and the roller is still there (mine broke off)
Depending on the roller tip and the status of the lifter, Replace the lifters under both heads, perhaps the cam if need be, continue on with life. Punch your brother in the nuts.
Depending on the roller tip and the status of the lifter, Replace the lifters under both heads, perhaps the cam if need be, continue on with life. Punch your brother in the nuts.
Thread Starter
Staging Lane
Joined: Aug 2019
Posts: 97
Likes: 5
That is how mine sounded when my lifter destroyed my ls1. Don't start it anymore, drain the oil and see what if any debris comes out. Pull the head remove the lifters. Pray the lifter just collapsed and the roller is still there (mine broke off)
Depending on the roller tip and the status of the lifter, Replace the lifters under both heads, perhaps the cam if need be, continue on with life. Punch your brother in the nuts.
Depending on the roller tip and the status of the lifter, Replace the lifters under both heads, perhaps the cam if need be, continue on with life. Punch your brother in the nuts.
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From: Central Cal.
Because if the lifter went south and grenaded the roller, it would destroy the lobe. IF the roller did survive intact, cam should be OK.
Thread Starter
Staging Lane
Joined: Aug 2019
Posts: 97
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it still turns on! I am just making the decision not to turn it on! I will post a picture of the oil tomorrow. I’m assuming i don’t need to drop the pan? As long as I drain it and check it right?
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TECH Enthusiast
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I'd pull the valve covers and look for broken spring coil pieces.
Wiggle push and pull on the rocker arms looking for something loose in the valvetrain. If you find something not right at least you'll know which head to pull first... of the two.
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Staging Lane
Joined: Aug 2019
Posts: 97
Likes: 5
Sorry I misread that... to "it won't start anymore
I'd pull the valve covers and look for broken spring coil pieces.
Wiggle push and pull on the rocker arms looking for something loose in the valvetrain. If you find something not right at least you'll know which head to pull first... of the two.
I'd pull the valve covers and look for broken spring coil pieces.
Wiggle push and pull on the rocker arms looking for something loose in the valvetrain. If you find something not right at least you'll know which head to pull first... of the two.
Not sure if you are a mechanic or not but there is a great guide on LS1howto that shows how to removed the heads. I'm a youtube mechanic so that guide was great.
--Also, as previously stated, if the lifter did turn or come apart, it more than likely messed up the lobe on the cam and thus the cam would need to be replaced or perhaps the motor like me.
Best of luck!! Here is a picture of my "tapping" lifter. I hope it is not this for your sake lol
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Thread Starter
Staging Lane
Joined: Aug 2019
Posts: 97
Likes: 5
I always hope for the best finding something irregular up top. If you have an issue like the photo of the lifter above... you will easily find that by removing the valve covers and wiggling/pushing on the rockers and pushrods. I've seen broken springs still holding the valve in place with pieces of the coils laying on top of the head that mimic the same sound. A rod knock can be isolated by removing one plug wire at a time. Without that cylinder firing the knock is diminished somewhat. I understand you not wanting to re-fire the engine.
Bru I almost have the right side valve off. Got all coils off just don’t know how to remove this hose lookin thing from the back. The passenger side is really annoying cuz there’s 2 hoses going to the back that are blocking me from remove some bolts and I can’t reach back far enough with something to release the the hose clamps..
The brake booster vac hose comes out with the manifold. Don't bother trying to undo it while the manifold is on.
Do yourself a favor and use www.ls1howto.com
there it will show you how to remove the manifold and then the heads. No guess work needed...
Do yourself a favor and use www.ls1howto.com
there it will show you how to remove the manifold and then the heads. No guess work needed...
Thread Starter
Staging Lane
Joined: Aug 2019
Posts: 97
Likes: 5
The brake booster vac hose comes out with the manifold. Don't bother trying to undo it while the manifold is on.
Do yourself a favor and use www.ls1howto.com
there it will show you how to remove the manifold and then the heads. No guess work needed...
Do yourself a favor and use www.ls1howto.com
there it will show you how to remove the manifold and then the heads. No guess work needed...
My own mechanical knowledge is limited so I don't really know how to check the lifters without looking at them aka pulling the head. I forget what person said you can tell by pushing on the rocker/pushrod side or something, perhaps he can shed more light on that.
The hose I though you were talking about was on the drivers side so I am not sure what hose you are referring to. I don't have any hoses on that side except a few PCV hoses
Originally Posted by 00cls1camaross
That is how mine sounded when my lifter destroyed my ls1. Don't start it anymore, drain the oil and see what if any debris comes out. Pull the head remove the lifters. Pray the lifter just collapsed and the roller is still there (mine broke off)
Depending on the roller tip and the status of the lifter, Replace the lifters under both heads, perhaps the cam if need be, continue on with life. Punch your brother in the nuts.
Depending on the roller tip and the status of the lifter, Replace the lifters under both heads, perhaps the cam if need be, continue on with life. Punch your brother in the nuts.
It does sound like a valve train noise but I wouldn’t pull the Intake off yet until the valve covers are off. Maybe you will get lucky and find something under the valve cover. I doubt it though. Good luck though and take your time
Thread Starter
Staging Lane
Joined: Aug 2019
Posts: 97
Likes: 5
Ahhhhhh, is this my problem? still haven’t done the other side, I’m not sure if this noise is normal, it only comes from some of them. I bet it’s my problem but can anyone tell me if I need to take the heads off? And I should probably check the other side right?
Thread Starter
Staging Lane
Joined: Aug 2019
Posts: 97
Likes: 5
https://youtu.be/CoXjtFAfI8E
still haven’t done the other side, I’m not sure if this noise is normal, it only comes from some of them. I bet it’s my problem but can anyone tell me if I need to take the heads off? And I should probably check the other side right?
still haven’t done the other side, I’m not sure if this noise is normal, it only comes from some of them. I bet it’s my problem but can anyone tell me if I need to take the heads off? And I should probably check the other side right?