LY6 issues... NEED HELP
03-20-2017, 08:10 PM
#22
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I know I have that front plug but is there any reason the rear plug would ever go bad? And if it was leaking alittle, would it cause an otherwise solid engine to only run 10 or 15 psi at idle?
03-22-2017, 04:03 PM
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I found that the oil galley front plug, and the rear dogbone diverter were not re-installed into the engine.
I have new ones already installed and both covers back on the motor. I tried cranking it over again and it still has no oil pressure. So I tried starting it for a few seconds to see if I could get it to prime up with the faster rotations, NOTHING.. I tried a mechanical gauge with the plastic tubing, I tried gauge right on the fitting, and I tried my digital gauge which will actually read as low as 3 or 4 pounds of pressure and it never moved.
It is not rattling or knocking. It fires up hard and runs good. But I just don't have a clue what could be the problem. It does move oil thru the galley and I assume thru the filter because when I removed the fittings to change the pressure senders, oil came running out. When I didn't have the plug in the front of the block and cranked it over, it pushed oil up thru there as well, but not at a high pressure or flow. I could put my thumb over the hole and it would not try to push my thumb back. There is a new O-ring on the pickup tube, I have tried 2 different oil pumps, both are used and one came off an engine I had running back in January. But both are from a Gen3 4.8/5.3 and this is a GEN4 6.0.
Any ideas would be appreciated.
I am certain that the dogbone is installed properly because the O-ring is at the back edge of the block.
Friend of mine thinks it could be a cracked crankshaft not letting the pressure build up, or possibly a bad oil pump(s).
I would like to try the Melling High volume with a brand new pickup tube and O-ring before calling it quits and having to tear it completely apart again to see if anything is amiss. I did clean the pickup tube and screen on this one and installed a new o-ring, but I am completely at a loss.
Are there any other internal plugs or ports that I might have missed closing off that they would have removed a plug from for dipping the block?
I have new ones already installed and both covers back on the motor. I tried cranking it over again and it still has no oil pressure. So I tried starting it for a few seconds to see if I could get it to prime up with the faster rotations, NOTHING.. I tried a mechanical gauge with the plastic tubing, I tried gauge right on the fitting, and I tried my digital gauge which will actually read as low as 3 or 4 pounds of pressure and it never moved.
It is not rattling or knocking. It fires up hard and runs good. But I just don't have a clue what could be the problem. It does move oil thru the galley and I assume thru the filter because when I removed the fittings to change the pressure senders, oil came running out. When I didn't have the plug in the front of the block and cranked it over, it pushed oil up thru there as well, but not at a high pressure or flow. I could put my thumb over the hole and it would not try to push my thumb back. There is a new O-ring on the pickup tube, I have tried 2 different oil pumps, both are used and one came off an engine I had running back in January. But both are from a Gen3 4.8/5.3 and this is a GEN4 6.0.
Any ideas would be appreciated.
I am certain that the dogbone is installed properly because the O-ring is at the back edge of the block.
Friend of mine thinks it could be a cracked crankshaft not letting the pressure build up, or possibly a bad oil pump(s).
I would like to try the Melling High volume with a brand new pickup tube and O-ring before calling it quits and having to tear it completely apart again to see if anything is amiss. I did clean the pickup tube and screen on this one and installed a new o-ring, but I am completely at a loss.
Are there any other internal plugs or ports that I might have missed closing off that they would have removed a plug from for dipping the block?
03-22-2017, 05:03 PM
#27
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No. when trying to diagnose the problem, I had the front timing cover off when cranking it over, and nothing was leaking from there. And there was no oil residue on the front of the block either.
I just spent 29 minutes on the phone with a mechanic at the GM dealer here in town. he thinks its the oil pump. So apparently I have 2 bad pumps. I am going to order a new Melling high volume oil pump when I get back to work and start getting some money in.
I just spent 29 minutes on the phone with a mechanic at the GM dealer here in town. he thinks its the oil pump. So apparently I have 2 bad pumps. I am going to order a new Melling high volume oil pump when I get back to work and start getting some money in.
03-22-2017, 05:48 PM
#28
Cant see 2 different pumps being bad, and not giving you any pressure... would think even if the pumps were worn out one of them would give you something, especially if one was working fine previously! I agree get a new pump but something is going on, bearing clearance somewhere, oring on valley plate not sealing, something..... have you tried pulling the top plate and seeing if you have oil coming out of the dod supply ports while its cranking, and to check those seals? Assuming you plastigaged the rod/main bearing!
03-22-2017, 05:58 PM
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rods were .0015 to .002
all 5 mains were .002
top plate is a new ICT Billet plate with all new O-rings I am not really wanting to remove the intake to mess with that when the oil pump is a possibility. One of them has been sitting for quite a while, and the other came off a running engine earlier this year.
But to be safe and to prevent me having a stroke over the seal being damaged on the ICT plate, I will grab a Melling High Volume pump first. The mechanic thinks the relief valve may be bad or weak which would let it go by before building pressure. Neither of us could identify or guess of any other plugs that would be causing the issue. and with my gauge being right at the filter, it should be reading pump pressure direct from the pump before it reaches any bearing journals. I know that the back pressure is what actually builds the pressure, but surely SOMETHING would show up on the gauge. I have zero, wo whatever is being pumped, is not being pumped hard enough to build the back pressure, but is being pumped enough to keep it from letting it rattle.
Other than that, I have NO CLUE
all 5 mains were .002
top plate is a new ICT Billet plate with all new O-rings I am not really wanting to remove the intake to mess with that when the oil pump is a possibility. One of them has been sitting for quite a while, and the other came off a running engine earlier this year.
But to be safe and to prevent me having a stroke over the seal being damaged on the ICT plate, I will grab a Melling High Volume pump first. The mechanic thinks the relief valve may be bad or weak which would let it go by before building pressure. Neither of us could identify or guess of any other plugs that would be causing the issue. and with my gauge being right at the filter, it should be reading pump pressure direct from the pump before it reaches any bearing journals. I know that the back pressure is what actually builds the pressure, but surely SOMETHING would show up on the gauge. I have zero, wo whatever is being pumped, is not being pumped hard enough to build the back pressure, but is being pumped enough to keep it from letting it rattle.
Other than that, I have NO CLUE