Debris in LT1 Oil
Thread Starter
Instructor
Joined: Mar 2002
Posts: 105
Likes: 1
From: Leesburg VA
Debris in LT1 Oil
So I got the oil pan off and found debris in the oil I was not expecting.
The debris I was expecting was the teeth from my water pump drive gear - of which I found at least one of the two that were missing.
http://forums.corvetteforum.com/c4-t...g-ticking.html
But I also found silver droplet shaped bits, 1.0 to 2.0 mm in diameter. They are steel or iron (and can be picked up with a magnet).
http://forums.corvetteforum.com/phot...68980/cat/1064
What am I seeing?
I have not taken the oil pump or tray off yet, so I have not done a full visual inspection of the underside of each piston. Should I pull a main or rod bearing to check clearances and look for other debris? Should I pull the intake or heads? Besides the noise from the cam gear, everything else seemed to be running fine - except for the opti was apparently about to fail on me after inspection (bad bearing and nearly failed rotor.)
Note: this car is an 1994 LT1 with 115,000 miles.
The debris I was expecting was the teeth from my water pump drive gear - of which I found at least one of the two that were missing.
http://forums.corvetteforum.com/c4-t...g-ticking.html
But I also found silver droplet shaped bits, 1.0 to 2.0 mm in diameter. They are steel or iron (and can be picked up with a magnet).
http://forums.corvetteforum.com/phot...68980/cat/1064
What am I seeing?
I have not taken the oil pump or tray off yet, so I have not done a full visual inspection of the underside of each piston. Should I pull a main or rod bearing to check clearances and look for other debris? Should I pull the intake or heads? Besides the noise from the cam gear, everything else seemed to be running fine - except for the opti was apparently about to fail on me after inspection (bad bearing and nearly failed rotor.)
Note: this car is an 1994 LT1 with 115,000 miles.
Last edited by rockken_vette; Jan 3, 2009 at 10:49 PM.
Team Owner
Joined: Mar 2001
Posts: 30,858
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From: Boston, Dallas, Detroit, SoCal, back to Boston MA
That's gear teeth!
You need to replace at least the drive and the timing gear set.
Take a look at the block where the drive sits as well as the cover
Ouch!
You need to replace at least the drive and the timing gear set.
Take a look at the block where the drive sits as well as the cover
Ouch!
Thread Starter
Instructor
Joined: Mar 2002
Posts: 105
Likes: 1
From: Leesburg VA
too much material
Yes, for sure 1 piece is a tooth from the water pump driven gear, maybe 1 1/2 teeth. Only 2 are missing, and the rest are fine. The Cam sprocket/gear has all its teeth, and 3 are slightly damaged. I have a new timing chain, cam gear/sprocket, and a used WP driven gear to install.
I know the pic has not been released yet, but there seems to be more material that I found in the pan than I thought I was missing. The gear has a golden appearance, as does the tooth I found (obvious). But what are the silvery ***** of metal.
Another small note fwiw ::: on occasion I have had a problem where it would blow bubbles out through the coolant fill reservoir. It never overflowed, just made noise. It never overheated (according to the gauges) either. I thought I might have had a pinhole in a cylinder head or a small head gasket issue, but I would be guessing.
I know the pic has not been released yet, but there seems to be more material that I found in the pan than I thought I was missing. The gear has a golden appearance, as does the tooth I found (obvious). But what are the silvery ***** of metal.
Another small note fwiw ::: on occasion I have had a problem where it would blow bubbles out through the coolant fill reservoir. It never overflowed, just made noise. It never overheated (according to the gauges) either. I thought I might have had a pinhole in a cylinder head or a small head gasket issue, but I would be guessing.
Last edited by rockken_vette; Jan 3, 2009 at 10:44 PM. Reason: not aluminum.
Thread Starter
Instructor
Joined: Mar 2002
Posts: 105
Likes: 1
From: Leesburg VA
Should I pull bearing caps? check clearances?
More info:
It looks like 3 or 4 of the debris pieces can be directly linked to the WP gear and cam sprocket gear. The small, silver round ***** are not aluminum, as I checked them with a magnet. The largest of the 9 ***** is 2mm x 3mm. The rest are approximately 1 to 2mm in diameter. They look a bit like casting flash, but I just don't know. The undersides of pistons 7 and 8 (5 and 6 to a much lesser extent) have some marks on them that look like they were nicked by something flying around in the crankcase, but it does not look like anything is really damaged beyond a superficial nick.
The engine has 115K miles on it. I wonder If I should mess with removing a rod cap or main bearing cap to see if there is any debris in the bearings. I seemed to have (what I thought) was good oil pressure for the age of the car, 50-60psi cold, 20-30psi hot, at idle before I tore everything apart. At higher RPMs, Oil pressure would come up as expected, mybe 60psi max warm.? I also checked clearance between connecting rods and found 0.017 to 0.019".
Thoughts? I'd like to start buttoning everything back up.
Ken
It looks like 3 or 4 of the debris pieces can be directly linked to the WP gear and cam sprocket gear. The small, silver round ***** are not aluminum, as I checked them with a magnet. The largest of the 9 ***** is 2mm x 3mm. The rest are approximately 1 to 2mm in diameter. They look a bit like casting flash, but I just don't know. The undersides of pistons 7 and 8 (5 and 6 to a much lesser extent) have some marks on them that look like they were nicked by something flying around in the crankcase, but it does not look like anything is really damaged beyond a superficial nick.
The engine has 115K miles on it. I wonder If I should mess with removing a rod cap or main bearing cap to see if there is any debris in the bearings. I seemed to have (what I thought) was good oil pressure for the age of the car, 50-60psi cold, 20-30psi hot, at idle before I tore everything apart. At higher RPMs, Oil pressure would come up as expected, mybe 60psi max warm.? I also checked clearance between connecting rods and found 0.017 to 0.019".
Thoughts? I'd like to start buttoning everything back up.
Ken
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Joined: Apr 2005
Posts: 3,624
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From: Dale City VA
More info:
It looks like 3 or 4 of the debris pieces can be directly linked to the WP gear and cam sprocket gear. The small, silver round ***** are not aluminum, as I checked them with a magnet. The largest of the 9 ***** is 2mm x 3mm. The rest are approximately 1 to 2mm in diameter. They look a bit like casting flash, but I just don't know. The undersides of pistons 7 and 8 (5 and 6 to a much lesser extent) have some marks on them that look like they were nicked by something flying around in the crankcase, but it does not look like anything is really damaged beyond a superficial nick.
The engine has 115K miles on it. I wonder If I should mess with removing a rod cap or main bearing cap to see if there is any debris in the bearings. I seemed to have (what I thought) was good oil pressure for the age of the car, 50-60psi cold, 20-30psi hot, at idle before I tore everything apart. At higher RPMs, Oil pressure would come up as expected, mybe 60psi max warm.? I also checked clearance between connecting rods and found 0.017 to 0.019".
Thoughts? I'd like to start buttoning everything back up.
Ken
It looks like 3 or 4 of the debris pieces can be directly linked to the WP gear and cam sprocket gear. The small, silver round ***** are not aluminum, as I checked them with a magnet. The largest of the 9 ***** is 2mm x 3mm. The rest are approximately 1 to 2mm in diameter. They look a bit like casting flash, but I just don't know. The undersides of pistons 7 and 8 (5 and 6 to a much lesser extent) have some marks on them that look like they were nicked by something flying around in the crankcase, but it does not look like anything is really damaged beyond a superficial nick.
The engine has 115K miles on it. I wonder If I should mess with removing a rod cap or main bearing cap to see if there is any debris in the bearings. I seemed to have (what I thought) was good oil pressure for the age of the car, 50-60psi cold, 20-30psi hot, at idle before I tore everything apart. At higher RPMs, Oil pressure would come up as expected, mybe 60psi max warm.? I also checked clearance between connecting rods and found 0.017 to 0.019".
Thoughts? I'd like to start buttoning everything back up.
Ken
The small round debris could be parts of the support bearing (ball) for the WP drive gear. Check its condition closely before you put a new WP drive assy in it.
They could also just be teeth off the WP drive gear that got chewed up and spit out eventually.
As much as I HATE to re-crush brgs... with chunks of metal that big floating around in the pan, I'd have to pull the caps to see what kind of damage the smaller chunks (the ones you haven't found yet) did.
I'd also check the oil pump strainer and depending on what I saw there, probally the condition of the oil pump gears.
Will
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Burning Brakes
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From: fighter pilots make movies, bomber pilots make history
Kenneth,
If your oil screen is intact, you do not have any metal going thru the oil pressure system (after pump). That metal has been knocking around in the lower block, but probably no bearing damage
Since you have the pan off, you might as well check the bearings, but I bet they are OK. Save your money for the real Vette the 65 you are restoring.
Joe
If your oil screen is intact, you do not have any metal going thru the oil pressure system (after pump). That metal has been knocking around in the lower block, but probably no bearing damage
Since you have the pan off, you might as well check the bearings, but I bet they are OK. Save your money for the real Vette the 65 you are restoring.
Joe
Thread Starter
Instructor
Joined: Mar 2002
Posts: 105
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From: Leesburg VA
bearing status...
I decided to take the rod bearings off. So far, i have just looked at all the cap sides, and they are all worn. Plastiguage said about 0.0035" clearance. I have ordered a replacemnt set of stock sized bearings, for $28.
The last bearing (closest to the back of the block (I don't remember if it was 7 or 8) seemed to have some debris in it, away from the center wear area. Not bad, but not like all the rest.
I also took apart the oil pump, and found the gear teeth to be slightly marked. It didn't look like there was any damage that was causing any problems though. I plan on re-using the pump.
I have not pulled any mains.
Ken
The last bearing (closest to the back of the block (I don't remember if it was 7 or 8) seemed to have some debris in it, away from the center wear area. Not bad, but not like all the rest.
I also took apart the oil pump, and found the gear teeth to be slightly marked. It didn't look like there was any damage that was causing any problems though. I plan on re-using the pump.
I have not pulled any mains.
Ken
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From: Dale City VA