I agree, it sounds like that piston is stuck again.
Oil pump question.
Thread Starter
Melting Slicks
Joined: Aug 2006
Posts: 2,167
Likes: 11
From: Powell TN
Cruise-In VIII Veteran
It runs great and feels strong. It is an automatic with the 2.73 gear, and feels every bit as strong as my 6 speed C5 with about 420 crank hp.
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Man,,,, I feel bad for you!
I "KNOW" how much it SUCKS to pull the front of that engine apart more than once!
Your only guessing if you don't pull it apart and check. The oil pump goes straight to the oil filter and from the filter to the oil pressure sensor which is at the entry of the lifter and main bearing galleries.
If you have LOW oil pressure, the engine will still run without weird noises. The lifters will be the first to show signs of no oil pressure. You will start to hear them tap when there is no oil pressure.
Unless the oil pick up is clogged again or the pump relief is stuck partially open, the next thing would be main bearings. If you pull the pan to check the pick up strainer, pull a main bearing cap and see how they look.
BC
I "KNOW" how much it SUCKS to pull the front of that engine apart more than once! Your only guessing if you don't pull it apart and check. The oil pump goes straight to the oil filter and from the filter to the oil pressure sensor which is at the entry of the lifter and main bearing galleries.If you have LOW oil pressure, the engine will still run without weird noises. The lifters will be the first to show signs of no oil pressure. You will start to hear them tap when there is no oil pressure.
Unless the oil pick up is clogged again or the pump relief is stuck partially open, the next thing would be main bearings. If you pull the pan to check the pick up strainer, pull a main bearing cap and see how they look.
BC
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
I just had the exact same problem. The pressure relief valve had about 3 pieces of metal shavings in it from someone porting it and not completely cleaning it. The piston was stuck open slightly and caused it to have 0 oil pressure until I revved it up. Then it had too much pressure. This was because the piston wouldn't move up or down. If you rev it up cold and have over 75 psi, the piston's stuck again I'm sure. You may start it and have no oil pressure at all until you bump the throttle. If you bump it and still have nothing, shut it down and start tearing it apart. The problem with having this stuff in your oil passages is that it can clog up your lifters, pushrods and other small clearance oil passages. As much as it hurts to hear this, it might be time to remove the entire engine and clean it thoroughly.
Thread Starter
Melting Slicks
Joined: Aug 2006
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Likes: 11
From: Powell TN
Cruise-In VIII Veteran
That's a normal 1/2" drive beside it.
If you have LOW oil pressure, the engine will still run without weird noises. The lifters will be the first to show signs of no oil pressure. You will start to hear them tap when there is no oil pressure.
Unless the oil pick up is clogged again or the pump relief is stuck partially open, the next thing would be main bearings. If you pull the pan to check the pick up strainer, pull a main bearing cap and see how they look.
BC
Unless the oil pick up is clogged again or the pump relief is stuck partially open, the next thing would be main bearings. If you pull the pan to check the pick up strainer, pull a main bearing cap and see how they look.
BC
I just had the exact same problem. The pressure relief valve had about 3 pieces of metal shavings in it from someone porting it and not completely cleaning it. The piston was stuck open slightly and caused it to have 0 oil pressure until I revved it up. Then it had too much pressure. This was because the piston wouldn't move up or down. If you rev it up cold and have over 75 psi, the piston's stuck again I'm sure. You may start it and have no oil pressure at all until you bump the throttle. If you bump it and still have nothing, shut it down and start tearing it apart. The problem with having this stuff in your oil passages is that it can clog up your lifters, pushrods and other small clearance oil passages. As much as it hurts to hear this, it might be time to remove the entire engine and clean it thoroughly.
Tech Contributor
Joined: May 2008
Posts: 2,843
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From: Howell Michigan
St. Jude Donor '09-'10-'11
What was odd was, while I was driving, any time I let off of the gas, the oil pressure would increase around 10 psi. For example, if I was driving along and the readout was showing 17 psi, as soon as I let off it would increase to 25-27 psi. If the readout was showing 21 psi, the psi would increase to 30-31 psi. I even drove down a long downhill section and the oil pressure stayed up the whole way down, until I got back on the throttle. I still don't hear any abnormal noise out of the bottom end.
Does this sound like bearings? or is the pressure relief valve stuck open again?
Does this sound like bearings? or is the pressure relief valve stuck open again?
Keep us posted on your progress.
Regards,
Eric D
Drifting
Joined: Jul 2001
Posts: 1,312
Likes: 2
From: Lake Havasu City AZ
If its a bearing, it will act the same every time you start it cold as the oil and tolerances will be the same. If its debris in the valve, it won't. If its debris get some cheap filters and let it idle in the garage and do multiple filter changes. It shouldn't hurt the engine if you monitor it and shut it down if it falls below the spec of 10 psi/K of RPM.
I have a hard time thinking a paper towel could jam open the valve. Put a paper towel in a blender and see what happens...its pulp.
Mike V
I have a hard time thinking a paper towel could jam open the valve. Put a paper towel in a blender and see what happens...its pulp.
Mike V
Thread Starter
Melting Slicks
Joined: Aug 2006
Posts: 2,167
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From: Powell TN
Cruise-In VIII Veteran
I started it again late today, so that the oil was completely cooled off. Pressure was immediately 38 lbs., nearly the same as yesterday when it was 42 lbs. at idle. Is this even normal LS2 oil pressure on a "new" motor? My 100,000 mile C5 has 48 lbs at idle.
I almost forgot to post the pics of the stuff I found after filtering everything through a paint filter. I poured all the oil through the filter and washed the oil filter media into it.
After I cleaned it and let it dry, this is what I ended up with. I really expected more material than this.
You can see a couple of metallic looking pieces in it, but it isn't supposed to do this is it?
I almost forgot to post the pics of the stuff I found after filtering everything through a paint filter. I poured all the oil through the filter and washed the oil filter media into it.
After I cleaned it and let it dry, this is what I ended up with. I really expected more material than this.
You can see a couple of metallic looking pieces in it, but it isn't supposed to do this is it?
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Thread Starter
Melting Slicks
Joined: Aug 2006
Posts: 2,167
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From: Powell TN
Cruise-In VIII Veteran
Right click, save. Thanks Bill, that's a lot better than what's in the service manual.
That's the first thing I'll do. In fact, I was thinking of draining the oil out of the oil pan directly through a filter also.
So, I should have low/no pressure when the oil is cold also? 38 lbs doesn't sound too bad, except when I start my 100,000 mile LS1 and it has 10-12 lbs more.
I think the paper tower they are talking about are the "shop" type. I have some and it is all you can do to tear them in half. I don't know what they are reinforced with, but it is stout stuff.
The low pressure could be a bad main or rod bearing, however I would suggest pulling the current oil filter off, and cutting it open before tearing everything down on the engine. Inspect it and see if you have the fiber stuff in it again. As long as you don't find anything metallic, I would replace the filter and try it again. You didn't have a means the first time to flush all the oil passages. They might be clear now.
Keep us posted on your progress.
Regards,
Eric D
Keep us posted on your progress.
Regards,
Eric D
If its a bearing, it will act the same every time you start it cold as the oil and tolerances will be the same. If its debris in the valve, it won't. If its debris get some cheap filters and let it idle in the garage and do multiple filter changes. It shouldn't hurt the engine if you monitor it and shut it down if it falls below the spec of 10 psi/K of RPM.
I think the paper tower they are talking about are the "shop" type. I have some and it is all you can do to tear them in half. I don't know what they are reinforced with, but it is stout stuff.
Drifting
Joined: Jul 2001
Posts: 1,312
Likes: 2
From: Lake Havasu City AZ
If it was a shop towel, I think it would still have some color in it if it were tinted. If you have metal in it, of course your problems are more serious than the fibers.
Good Luck.
Mike V
Good Luck.
Mike V
Pro
Joined: Aug 2007
Posts: 619
Likes: 1
From: ATLANTA GA
Have you considered the thought of installing a oil filter bypass for diagnosis only?
Thoroughly clean everything again, infact before the crank is damaged by any of the bearings Id go ahead and slide new bearings in both the rods and the mains(they are cheap)
- Micropolish the pump piston valve, and its bore, so hopefully it would resist binding again,
- Do the shim mod by adding a .100" shim on the end of the spring, make it to where it fits within the allen head plug, This gives the pump MUCH more spring pressure again to resist binding within the bore, you will also notice more oil pressure by it not cutting off at 65PSI
-Install the Filter bypass setup and see if pressure issue is fixed, then you can reinstall the filter id be changing oil frequently for awhile..
Thoroughly clean everything again, infact before the crank is damaged by any of the bearings Id go ahead and slide new bearings in both the rods and the mains(they are cheap)
- Micropolish the pump piston valve, and its bore, so hopefully it would resist binding again,
- Do the shim mod by adding a .100" shim on the end of the spring, make it to where it fits within the allen head plug, This gives the pump MUCH more spring pressure again to resist binding within the bore, you will also notice more oil pressure by it not cutting off at 65PSI
-Install the Filter bypass setup and see if pressure issue is fixed, then you can reinstall the filter id be changing oil frequently for awhile..
Last edited by vettekidc5; Aug 4, 2008 at 03:37 PM.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
38psi is acceptable at idle. Rev the engine and see how much it goes up to cold to make sure the bypass is working. When my bypass was stuck, it went to 93psi. Remember that one little piece of trash in your pump could seize your bypass piston again. You would be amazed at the small size of the pieces that froze up mine. There were only 3 pieces that you could only see on a Qtip. I would recommend you at least pull the lower section of the oil pan and clean it well. The gasket is definitely reusable. You might even consider epoxying some strong magnets to the floor of the oil pan to help catch garbage before getting recycled through the pump.
Thread Starter
Melting Slicks
Joined: Aug 2006
Posts: 2,167
Likes: 11
From: Powell TN
Cruise-In VIII Veteran
Have you considered the thought of installing a oil filter bypass for diagnosis only?
Thoroughly clean everything again, infact before the crank is damaged by any of the bearings Id go ahead and slide new bearings in both the rods and the mains(they are cheap)
- Micropolish the pump piston valve, and its bore, so hopefully it would resist binding again,
- Do the shim mod by adding a .100" shim on the end of the spring, make it to where it fits within the allen head plug, This gives the pump MUCH more spring pressure again to resist binding within the bore, you will also notice more oil pressure by it not cutting off at 65PSI
-Install the Filter bypass setup and see if pressure issue is fixed, then you can reinstall the filter id be changing oil frequently for awhile..
Thoroughly clean everything again, infact before the crank is damaged by any of the bearings Id go ahead and slide new bearings in both the rods and the mains(they are cheap)
- Micropolish the pump piston valve, and its bore, so hopefully it would resist binding again,
- Do the shim mod by adding a .100" shim on the end of the spring, make it to where it fits within the allen head plug, This gives the pump MUCH more spring pressure again to resist binding within the bore, you will also notice more oil pressure by it not cutting off at 65PSI
-Install the Filter bypass setup and see if pressure issue is fixed, then you can reinstall the filter id be changing oil frequently for awhile..
I thought about the shim mod when I was in there before, but I didn't know what thickness. Thanks
38psi is acceptable at idle. Rev the engine and see how much it goes up to cold to make sure the bypass is working. When my bypass was stuck, it went to 93psi. Remember that one little piece of trash in your pump could seize your bypass piston again. You would be amazed at the small size of the pieces that froze up mine. There were only 3 pieces that you could only see on a Qtip. I would recommend you at least pull the lower section of the oil pan and clean it well. The gasket is definitely reusable. You might even consider epoxying some strong magnets to the floor of the oil pan to help catch garbage before getting recycled through the pump.
I'm going to take a rod cap off and see what it looks like. And like vettekidc5 said, I'll probably at least put new rod bearings in it. They are the ones that take the most abuse, so would probably be the first to go.
Any ideas on why the oil pressure would go up 10 psi when I let off of the gas? Since it's an auto, the rpms go down, but the pressure would go up. As soon as I got back in the gas, oil pressure went back down.
Thread Starter
Melting Slicks
Joined: Aug 2006
Posts: 2,167
Likes: 11
From: Powell TN
Cruise-In VIII Veteran
That was with cold oil. After driving ~30 miles the oil pressure at idle was only 6 lbs.
I did this and my pressure rose up to nearly 70 lbs. It sounds like I may have multiple problems. A stuck pressure valve and some bad bearings.
I bet not nearly as interesting as you taking a Sawzall to your roof.
I bet not nearly as interesting as you taking a Sawzall to your roof.
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
^ Haha... Im just impressed by your willingness to tear into the car in your garage to this length. Never seen anything like those fibers in a motor, curious as to what the outcome will be.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
Well, if the piston is stuck in a different position and barely open, it will cause both low pressure and high pressure as this is exactly what happened to me. Just be careful with the pump when removing it not to jar anything so you can analyze the piston position when you get it apart. Or you can take the pump cover off and gears out in the car and take a look before removing the pump body. I'm anxious to see what you find.
Burning Brakes
Joined: Nov 2004
Posts: 781
Likes: 0
Do you have any tangible proof that the engine has actually been pulled out and rebuilt?
?Any physical indications that it has been torn down/reassembled (silicone on gaskets, tool marks/used bolts, obviously new parts... stuff like this?) ?
?Any physical indications that it has been torn down/reassembled (silicone on gaskets, tool marks/used bolts, obviously new parts... stuff like this?) ?