LS7 Possible Stuck Lifter?
Thread Starter
Cruising
Joined: Oct 2021
Posts: 11
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LS7 Possible Stuck Lifter?
First post on my new to me 2007 C6 Z06! It's just unfortunate it isn't a positive one but nonetheless I need some help diagnosing this sound i've been hearing lately on cold start (i know its one of those "what's that sound posts"). It only happens occasionally when its a little cold and lasts for a few minutes of driving after which it quietens down. My guess is its a leaky lifter that's slow to pump up. I'm pulling my heads for a different reason so I'll be able to inspect the lifters. What should I look for to properly diagnose the problem?
Video of the noise I'm hearing:
Video of the noise I'm hearing:
Race Director
Joined: Dec 2005
Posts: 11,888
Likes: 107
From: God's Country, ID
First post on my new to me 2007 C6 Z06! It's just unfortunate it isn't a positive one but nonetheless I need some help diagnosing this sound i've been hearing lately on cold start (i know its one of those "what's that sound posts"). It only happens occasionally when its a little cold and lasts for a few minutes of driving after which it quietens down. My guess is its a leaky lifter that's slow to pump up. I'm pulling my heads for a different reason so I'll be able to inspect the lifters. What should I look for to properly diagnose the problem?
Video of the noise I'm hearing: https://youtu.be/3q_5vSbNd0k
Video of the noise I'm hearing: https://youtu.be/3q_5vSbNd0k
Race Director
Joined: Dec 2013
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Would check the cam lobs as well, since if the trays are allowing the lifters to rotate in the trays, your going to have cam lob damage as well.
As for head, would do a full pull down to check the amount of lash between the valve stems and the valve guides too. On some of the Lt1 motors in the C7, the bottom of the valve guides where chamfered, but not the top side channels; leaving sharp edge burs that would break off under the valve seals to drop down between the guides stems, to either egg out the top of channels if the piece could work it way down to pass down to drop out the bottom, or if a big enough bur that broke off, stick the valves open to slap the pistons and break the valve isntead.
As for head, would do a full pull down to check the amount of lash between the valve stems and the valve guides too. On some of the Lt1 motors in the C7, the bottom of the valve guides where chamfered, but not the top side channels; leaving sharp edge burs that would break off under the valve seals to drop down between the guides stems, to either egg out the top of channels if the piece could work it way down to pass down to drop out the bottom, or if a big enough bur that broke off, stick the valves open to slap the pistons and break the valve isntead.
Thread Starter
Cruising
Joined: Oct 2021
Posts: 11
Likes: 2
Would check the cam lobs as well, since if the trays are allowing the lifters to rotate in the trays, your going to have cam lob damage as well.
As for head, would do a full pull down to check the amount of lash between the valve stems and the valve guides too. On some of the Lt1 motors in the C7, the bottom of the valve guides where chamfered, but not the top side channels; leaving sharp edge burs that would break off under the valve seals to drop down between the guides stems, to either egg out the top of channels if the piece could work it way down to pass down to drop out the bottom, or if a big enough bur that broke off, stick the valves open to slap the pistons and break the valve isntead.
As for head, would do a full pull down to check the amount of lash between the valve stems and the valve guides too. On some of the Lt1 motors in the C7, the bottom of the valve guides where chamfered, but not the top side channels; leaving sharp edge burs that would break off under the valve seals to drop down between the guides stems, to either egg out the top of channels if the piece could work it way down to pass down to drop out the bottom, or if a big enough bur that broke off, stick the valves open to slap the pistons and break the valve isntead.
Race Director
Joined: Dec 2005
Posts: 11,888
Likes: 107
From: God's Country, ID
At 60k I'd definitely be swapping them out. That was the aprox miles when I had an oem lifter let go in the turbo LS2 with a small cam.
I run a set of 2110 in a 403 stroker LS. I looked at the linked lifters but decided they were just overkill for my set-up.
Here's some additional info comparing several lifters (that has been posted before).
I run a set of 2110 in a 403 stroker LS. I looked at the linked lifters but decided they were just overkill for my set-up.
Here's some additional info comparing several lifters (that has been posted before).
Thread Starter
Cruising
Joined: Oct 2021
Posts: 11
Likes: 2
Thanks for the video that really helped clear things up! Based on that info and looking through some other posts I've settled on the regular 2110. I figured I don't need the reduced travel for my application and it'd help give me some leeway setting up the preload.
