oil pressure problems
09-28-2014, 09:59 PM
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oil pressure problems got a AES 390 shortblock stock heads running an F1A on around 12 lbs. Melling high volume pump. previously running 20w-50 Valvoline VR1 oil and having 60-80lbs oil pressure.
was out testing a tuning one night and oil pressure started acting wierd and dropping a good bit down to the point i was afraid to even run the engine. i made it a few miles home and shut it down, i replaced the oil pressure sensor twice to make sure it wasnt that. i also installed a mechanical gauge an had the same results.
i was going to install a new oil pan anyways so i did that and installed a new pickup and new oring, added fresh oil and nothing changed still oil pressure dropping to 5-10 lbs at idle. see video below.
my question is what the hell? what should i look for i got the cam out today and the bearings look perfect and none of the moving parts look hurt or damaged i cant see anything thats causing a problem, pulled the melling oil pump off and it seems fine. i'm really at a loss as to what to look for or what could be wrong. the engine made 0 noise or knock before i pulled it only very low pressure.
was out testing a tuning one night and oil pressure started acting wierd and dropping a good bit down to the point i was afraid to even run the engine. i made it a few miles home and shut it down, i replaced the oil pressure sensor twice to make sure it wasnt that. i also installed a mechanical gauge an had the same results.
i was going to install a new oil pan anyways so i did that and installed a new pickup and new oring, added fresh oil and nothing changed still oil pressure dropping to 5-10 lbs at idle. see video below.
my question is what the hell? what should i look for i got the cam out today and the bearings look perfect and none of the moving parts look hurt or damaged i cant see anything thats causing a problem, pulled the melling oil pump off and it seems fine. i'm really at a loss as to what to look for or what could be wrong. the engine made 0 noise or knock before i pulled it only very low pressure.
09-28-2014, 10:50 PM
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The sound your hearing is the procharge spinning. When I removed the belt there was no noticible noises from the engine that I could hear. Only noise I ever hear were the injectors clicking.
09-28-2014, 11:05 PM
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May be time to check the bearings else is the oil getting hot, do you have an aluminum body oil pump they crack.
I ones had an unusual case of low oil pressure when oil pan was removed I found something similar to a fur ball gathered at the oil pick up screen it looked like the pistons had let go of their skirt coating, after a thorough investigation it was the GM head gasket coating had come off and gathered at the pick up screen effectively blocking a good percentage of flow. I know these sound weird but happened to me.
That was the last time I used stock GM gaskets who knows where in China they came from.
Please let us know the outcome and good luck...
I ones had an unusual case of low oil pressure when oil pan was removed I found something similar to a fur ball gathered at the oil pick up screen it looked like the pistons had let go of their skirt coating, after a thorough investigation it was the GM head gasket coating had come off and gathered at the pick up screen effectively blocking a good percentage of flow. I know these sound weird but happened to me.
That was the last time I used stock GM gaskets who knows where in China they came from.
Please let us know the outcome and good luck...
09-28-2014, 11:16 PM
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May be time to check the bearings else is the oil getting hot, do you have an aluminum body oil pump they crack.
I ones had an unusual case of low oil pressure when oil pan was removed I found something similar to a fur ball gathered at the oil pick up screen it looked like the pistons had let go of their skirt coating, after a thorough investigation it was the GM head gasket coating had come off and gathered at the pick up screen effectively blocking a good percentage of flow. I know these sound weird but happened to me.
That was the last time I used stock GM gaskets who knows where in China they came from.
Please let us know the outcome and good luck...
I ones had an unusual case of low oil pressure when oil pan was removed I found something similar to a fur ball gathered at the oil pick up screen it looked like the pistons had let go of their skirt coating, after a thorough investigation it was the GM head gasket coating had come off and gathered at the pick up screen effectively blocking a good percentage of flow. I know these sound weird but happened to me.
That was the last time I used stock GM gaskets who knows where in China they came from.
Please let us know the outcome and good luck...
i'm running Cometic head gaskets and the old pickup was clean of debris along with the new one.
09-28-2014, 11:17 PM
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thought of that and changed to a new pickup and oring with the new oil pan and had the same problem, when i puled the pan today the pickup was sealed very well and looks perfect so i dont think its a problem with that part.
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09-29-2014, 12:49 PM
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got the back cover plate off and the last cam bearing looks fine, the rods have no play in them.
the reluctor wheel is a little discolored but the main bearing behind it looks fine.
the little plastic plug in the back looks ok i guess never had to inspect one before.
any ideas????
the reluctor wheel is a little discolored but the main bearing behind it looks fine.
the little plastic plug in the back looks ok i guess never had to inspect one before.
any ideas????
09-30-2014, 10:07 PM
#14
check for a leak at the cam plate...if its not sealed, you lose pressure
check for a leak at the oil pan, above the filter, if the o-ring on the pan gasket isnt good, it can blow oil directly back into the pan instead of thru the oil galley.
if a lifter has partially collapsed, it may not make any noise(as if you can hear it over the procharger anyways..LOL) but it could be allowing oil to get past and just dribble down into the pan instead of going thru the lifter and the oil galley (had it happen once to me)
you can use a pressure can and force feed oil thru the galleys and look and listen for leaks...
pull the front cover off and you can look thru the splash window for things up higher
(had to do that today to diagnose a leaky DOD delete kit on an LS3)
check for a leak at the oil pan, above the filter, if the o-ring on the pan gasket isnt good, it can blow oil directly back into the pan instead of thru the oil galley.
if a lifter has partially collapsed, it may not make any noise(as if you can hear it over the procharger anyways..LOL) but it could be allowing oil to get past and just dribble down into the pan instead of going thru the lifter and the oil galley (had it happen once to me)
you can use a pressure can and force feed oil thru the galleys and look and listen for leaks...
pull the front cover off and you can look thru the splash window for things up higher
(had to do that today to diagnose a leaky DOD delete kit on an LS3)
10-01-2014, 06:44 PM
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check for a leak at the cam plate...if its not sealed, you lose pressure
check for a leak at the oil pan, above the filter, if the o-ring on the pan gasket isnt good, it can blow oil directly back into the pan instead of thru the oil galley.
if a lifter has partially collapsed, it may not make any noise(as if you can hear it over the procharger anyways..LOL) but it could be allowing oil to get past and just dribble down into the pan instead of going thru the lifter and the oil galley (had it happen once to me)
you can use a pressure can and force feed oil thru the galleys and look and listen for leaks...
pull the front cover off and you can look thru the splash window for things up higher
(had to do that today to diagnose a leaky DOD delete kit on an LS3)
check for a leak at the oil pan, above the filter, if the o-ring on the pan gasket isnt good, it can blow oil directly back into the pan instead of thru the oil galley.
if a lifter has partially collapsed, it may not make any noise(as if you can hear it over the procharger anyways..LOL) but it could be allowing oil to get past and just dribble down into the pan instead of going thru the lifter and the oil galley (had it happen once to me)
you can use a pressure can and force feed oil thru the galleys and look and listen for leaks...
pull the front cover off and you can look thru the splash window for things up higher
(had to do that today to diagnose a leaky DOD delete kit on an LS3)
i checked those gaskets and i actually took the procharger belt off first to listen for noises haha
how do i force feed oil through them? i dont see any tapped holes to put a fitting or anything on, not to sure what your talking about i guess
i spoke with Brian at AES and he suggested a collapsed filter, but i've went through three filters and oil changes before i yanked the motor so i cant imagine that would be it unless it did and somehow sucked up something into a oil passage?
10-06-2014, 11:54 AM
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any other ideas? i hate to put it back in the truck and have the same problem, but i also dont want to pull the rotating assembly for no reason. kinda in limbo here lol
10-06-2014, 05:14 PM
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remove the pump and on the outside you'll see a bolt that is about 3/4" or soo in diameter and has a female hex hole , remove and check the piston for free travel in n out of bore . and check for debris in bore and piston . depending on the spring pressure you moght want to check pressure and shim for a higher over-pressure relief point. a cpl posts before you said brian at aes said maybe a collapsed "filter" . sure he did'nt say/mean a collapsed LIFTER ? good luck
10-06-2014, 05:36 PM
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remove the pump and on the outside you'll see a bolt that is about 3/4" or soo in diameter and has a female hex hole , remove and check the piston for free travel in n out of bore . and check for debris in bore and piston . depending on the spring pressure you moght want to check pressure and shim for a higher over-pressure relief point. a cpl posts before you said brian at aes said maybe a collapsed "filter" . sure he did'nt say/mean a collapsed LIFTER ? good luck
OK thanks I'll take a look at it when I get home!
And yeah I'm sure he said a filter and not a lifter, he said I should go to wix filtetd and avoid the paper element ones.
Is there a way to check the lifters before I put them back in?
