Spun bearing or Bad lifters
Thread Starter
Launching!
Joined: Nov 2008
Posts: 284
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From: Pembroke pines FL
Spun bearing or Bad lifters SO a little background: I have a 2002 Z06 that for a while has had a knocking noise right after a cold start that would subside and eventually stop as the car warmed up. I assumed this was a bad lifter at first till one day I start the car and it has NO OIL PRESSURE. I immediately shut it off and checked the oil level to make sure it wasent a hole in the oil pan or somthing. so that checked out and i started the car again and it built oil pressure but was at around 25psi instead of the normal 50psi or so.
so i preceded to let it sit for a while assuming i had to rebuild the engine and it has sat there for about 8 months now. yesterday i start it up to move it a bit, at this point im already convinced of a rebuild and doing a 383 stroker and all other things involved with that etc. and when it starts up it had NO OIL PRESSURE and was knocking a bit but then after a few seconds (maybe 20 seconds tops) it shoots up to 50psi as it would normally be and stayed there and the knock started to subside as before.
basically im asking can a bad lifter cause a low or no pressure reading. I have experienced this before with my brothers z28 and we ended up changing the lifters and oil pump and he hasent had an oil pressure issue since.
ill try to post a video of this when i can.
so i preceded to let it sit for a while assuming i had to rebuild the engine and it has sat there for about 8 months now. yesterday i start it up to move it a bit, at this point im already convinced of a rebuild and doing a 383 stroker and all other things involved with that etc. and when it starts up it had NO OIL PRESSURE and was knocking a bit but then after a few seconds (maybe 20 seconds tops) it shoots up to 50psi as it would normally be and stayed there and the knock started to subside as before.
basically im asking can a bad lifter cause a low or no pressure reading. I have experienced this before with my brothers z28 and we ended up changing the lifters and oil pump and he hasent had an oil pressure issue since.
ill try to post a video of this when i can.
On The Tree
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From: Houston
Thread Starter
Launching!
Joined: Nov 2008
Posts: 284
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From: Pembroke pines FL
Yes but I am trying to gauge if people have experience the same issues. I know bad lifters can knock but can they affect oil pressure. Im trying to verify if what I experienced before with the Z28 was a fluke or if that really was the solution to the problem.
mainly I want to know has anyone else seen bad lifters affect oil pressure like as I described. because i know a spun bearing can cause the same issue.
mainly I want to know has anyone else seen bad lifters affect oil pressure like as I described. because i know a spun bearing can cause the same issue.
TECH Addict
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Very little, you wouldn't be losing 25 psi through the lifters unless one was broken in pieces. You might see lifters causing oil pressure gauge fluctuating a small amount. Moore likely you have oil pump -pickup tube problems.
Thing to consider is the oil pump pickup tube oring letting air past it. This will cause noisy lifters and lower than normal oil pressure.
Thing to consider is the oil pump pickup tube oring letting air past it. This will cause noisy lifters and lower than normal oil pressure.
Last edited by RockinWs6; Aug 22, 2013 at 06:59 PM.
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From: So.Cal.
If a lifter was not present there would be a leak... if the lifter is present it restricts the leak (it regulates oil flow up the pushrods)... so a single lifter leaking (due to being internally stuck) may not cause that much drop in oil pressure, but maybe multiple lifters may.
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Verdad Gallardo TECH Addict
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Depends the orings can move around and depending on temperature seal or leak. Mine leaks down cold but warmed up seals ok. Cold start I get terrible valve clatter everytime until the air purges out of the lifters. Hot its quiet as a mouse once the oring gets warmed up and seals. Its gotta be changed soon.
The oring wear over time and shrink, the acids in the engine oil also attack them. Its not always a tear failure but usually a wear failure.
The oring wear over time and shrink, the acids in the engine oil also attack them. Its not always a tear failure but usually a wear failure.
Last edited by RockinWs6; Aug 23, 2013 at 07:34 PM.
TECH Addict
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If a lifter was not present there would be a leak... if the lifter is present it restricts the leak (it regulates oil flow up the pushrods)... so a single lifter leaking (due to being internally stuck) may not cause that much drop in oil pressure, but maybe multiple lifters may.
Thread Starter
Launching!
Joined: Nov 2008
Posts: 284
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From: Pembroke pines FL
So I have begun tearing into it. Took out one of the heads for now. I'll keep you guys posted. Will also be replacing heads and cam for a milled .030 243s and a .228/230 .571/.573 112 las cam. I don't think I should have any piston to valve clearance issues.
