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Oil pressure

This is a discussion on Oil pressure within the Internal Engine forums, part of the LSx Technical Help Section category; At the first week of idle the oil was at about 3 or 4 bars, which is roughly around 40 ...

  1. #1
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    1986 Turbo 944

    Oil pressure

    At the first week of idle the oil was at about 3 or 4 bars, which is roughly around 40 psi.

    After letting it run for its usual 30 mins for a few times over a week, I decided it was time to drive it. Seemed to be fine. After 3 weeks into the startup I took it to town the other day and after 5 mins into the drive I realized my oil pressure is dropping down past 1 bar, about 14 psi or less. The chevy mech man here told me the engine only need 4 psi per thousand to run.

    It has a brand new oil pump and brand new everything. I am running royal purple break in oil. I took the pressure sender off and tried to hook my manual gauge up but it only reads 25psi or above. So no go, I unhooked the oil sender and cranked the engine and the oil came out. So I have oil traveling my engine.

    There is no over heating problems, oil level is good and there are no leaks or unexplained smoking like a bad seal some where. Checked the gauge and have full movement. I am not sure what to do next. Please help.

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    Just to clarify a little, on my setup I am running a remote filter kit. The pan has ports on it that the oil lines connect to and run to the filter.

    I unhooked lines and had my wife turn the key over and saw oil come out of both lines, in and out, instead of just one.

    Does this sound like a pump issue?

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    10 psi of oil pressure per 1,000 r.p.m. is an old standby. Down to 14 psi under load = immediate shutdown in my book. Any chance you have a faulty sender and/or gauge? Best thing to do is test it with a master pressure gauge... which is a difficult thing to do on an F-body, but not so bad in other body styles. Your car, I have no clue.

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    I have checked with a master gauge and still no luck.

    I am not sure whats up yet, I am in the process of tearing down my front end to get the pan off and possibly the pump if everything looks good in the pan. I am hoping not to have to pull the whole engine out of the car.

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    OK....I am the slowest guy here so bear with me.
    "new oil pump and everything..."....I do not know what in the hell that means. Define "everything"......
    What kind of motor is this?
    What mods?
    Did you put a cam in it?
    Heads?
    What?

    When you say it ran for 30 minutes a day before you drove it....are you telling me you broke your engine in just letting it idle for 30 minutes a day?

    Sorry ....but I am lost here.

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    Never mind If you wasn't a good 'ol boy from Arkansas I would have just gone back to my newspaper and coffee......

    Do you by any chance have a Displacement on Demand Valley Tray in that? I went and read a bunch of your post and looked at your video's but could never find if the donor motor was a GM DoD motor or not?

    All bets are off until we find out what valley tray you have in there...............

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    You saw a pressure difference between the dash gauge and the unknown mechanical gauge -- that's why I recommended a master pressure gauge which should be a precisely calibrated unit. 25 psi at idle is not terrible -- but you did not provide any specifics. Does the pressure rise from there with increased rpms?

    Please answer Sarge's questions as he certainly knows what he is talking about (even when posting from a beach with a Tequila Sunrise in hand). Some more details would be very helpful...

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    no the master gauge would not even register. 25 psi is the first number and it didnt even get there.

    It is an LS1 block with LS6 heads. I rebuilt everything on this motor, cam, rockers, pushrods, bearings, rods, pistons, heads, crank was checked. All clearances double checked.

    The mods I am running are the LS6 heads, dual springs, 1.72 rockers, short lift lifters, Comp Cam 228/330 w/ .571 lift. Cloyes timing chain set. LS6 oil pump. Forged rods and Pistons.

    For the first week I would let the car run at idle until operating temp was reached, 202*F. I would let it run for about 20 more mins. I did this a few times over a week and made sure all the temps, pressures, and leaks were all good.

    I then took it on a couple 5 min test drives down the road and back at about 3k rpm.

    After that I took it to town, and about 5 mins into the Drive I saw the pressure gauge had dropped. I pulled over and double checked the engine and oil levels. I saw the break in oil was pretty thin so I let the car sit at O'reilly's for a couple hours to see if that helped. The pressure came back up to 3 bars and will increase slightly with rpm gain. Now it will get to 1 bar and not make much more of a move.

    Checked with a master gauge where the sender goes and the gauge would not register pressure. I then took the gauge out and turn over the engine, oil came out, so I have some oil traveling through the engine. I then looked into my filter relocation routing and made sure the lines were correct. That is when I found that the oil is being pumped both forwards and backwards to the filter. This would cause a pressure issue since there is not a single route it is taking.

    I have done further researched throughout the night and found that a pressure regulator valve in the pump could be the issue. Which this would make since if it is stuck open then the pressure is allowed to run both ways, like a turbo wastegate being stuck open, you could never build pressure past the main resistance of the tubes.

    I am taking apart the front of the car to double check the bottom end of the motor. I will drop the pan and pull the crank pulley to get to the pump. While I am there I will drop a rod cap and look at the bearings. Planning on taking off the valve covers and looking at the top end since that would be the place alot of oil issues would damage first.

    I hope this clears anything you were lost about up.
    What is this Displacement on demand Valley tray you are talking about? I am running stock Displacement.

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    Chevy made many DoD engines in the past few years. When you install a cam/lifters et all and leave the DoD valley tray it does exactly what you describe. You have to get a LS3 (2009 vette) valley tray to get oil pressure worth a shit.

    DoD valley trays have 4 big solenoids. If that is what you put back on there you need to replace it with a 09 Vette Valley Tray to get your oil pressure problem fixed.

    This is the valley tray
    http://www.google.com/imgres?imgurl=...ed=0CB8Q9QEwAg
    Last edited by Sarge; 12-26-2010 at 12:23 PM.

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    Ok, I dont understand how the oil pressure was good for the first week and then once I actually drove it it went down. The pressure issue does not solve why the oil is being pumped out of the inlet and outlet ports on the pan, does it?

    Sarge just curious how the valley tray affects the oil pressure, Mine looks just like that on top, are they different underneath?
    Last edited by cfgioja; 12-26-2010 at 02:43 PM.

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    Mine was fine for awhile also. Then those fucking solenoids start to bleed and "poof"...your oil pressure drops to shit. Yes you have to see if you have those 4 big ass solenoids underneath. The non DoD does not have them. You can use the same valley tray. Many guys just tap/screw in plugs and reuse the DoD valley tray.

    It made me crazy also. I cammed the Silverado and lost oil pressure....down to what you describe...of course I thought it was the ORing around the pickup tube or something. After awhile I found this is common as hell when going from DoD to Non DoD.

    Go ahead and check the normal oil pressure suspects. But I would take the valley cover off. You will see the big ass solenoids quickly. If you have them there is your problem. Very common. Takes what? 30 minutes to pull your intake and check.

    http://www.ls1tech.com/forums/genera...t-o-rings.html

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    I will make that part of my check too. I want to make sure anything that could be wrong is good.

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    Here man.....
    http://www.g8board.com/forums/showthread.php?t=19612

    You are not the first to have this happen. I was clueless about this DoD bullshit.
    Looked at my OP Gauge one day and had like 15lbs of oil pressure. I about shit......

    Actually...it is a easy fix....less than an hour. My local Chevy dealer had the 09 Vette valley cover for like $70 bucks and that was with gaskets and stuff.

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    Just curious, I didn't think any genIII had available dod.

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    The 5.3 in our 'Burb is a DOD engine. Even has a display that can be toggled on that reads either "V4 Mode" or "V8 Mode" to show the DOD in action.

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    Member Jay37's Avatar
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    I've melted alot of lead, and welded alot of galvanized steal in my day plus a couple car wrecks, I can be a little, slow.
    Anyway I don't think he has dod available in the ls1 or ls6 GM introduced it in the '05 gen IV models.
    Once you do all the above mentioned.
    Did you check the cam bearings and all the oil plugs are were there suppose to be? It seems to be common for the cam bearings to slide forward/aft and uncover the galley.
    Last edited by Jay37; 12-26-2010 at 07:44 PM.
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    I will double check the upper end after I finish the lower, I am trying to avoid dropping the engine again. Its hard enough to work inside my cramped bay let alone install all the bell housing bolts again. If you don't know from my profile, this engine is in my 944 turbo pporsche body.

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    Quote Originally Posted by Jay37 View Post
    Just curious, I didn't think any genIII had available dod.
    GM started it in 2001 with the Caddies. In 2003 they put it in the trucks and the Impala, Monte Carlo SS and of course in 2008 they started putting it in the many of the LS3's and announced it would be in the "new" Camaro.

    So it is in hundreds of thousands of V8 GM Blocks. This is why I was asking about the donor motor specific. As you know many of the donor motors ending up in our Hot Rods come from truck motors.

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