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350 chevy with low to no oil pressure

Discussion in 'The Hokey Ass Message Board' started by Dooley, Aug 22, 2012.

  1. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    i noticed low pressure on my 79 010 350 today, so I changed oil and filter 20-50 stp oil treat and ac delco filter...

    no oil pressure at all when started. So i shut it off. SW mech guage with clear tube for sender, and no oil was moving through the sender.

    I pulled the dizzy and used a drill and oil primer and finally got the oil pressure to move but it was low, only 20 or so with the drill full on. Put the dizz back and it gets oil pressure when revved, lower than ever, and it droppes to nothing at idle with no il moving through the clear tube sender...
    Is my pump shot?
    Relief valve?


    Car does not smoke or knock...
     
  2. Sphynx
    Joined: Jan 31, 2009
    Posts: 1,143

    Sphynx
    Member
    from Central Fl

    Could be cam bearings....
     
  3. Not the pump. Not all of a sudden.
     
  4. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    it has about 8 thou since it was fresh built....
    I did notice that my pcv/breather had come off before I pulled it out today and I thought that was the reason for the low pressure, but after the oil change it was worse...
     
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  5. maybe the pickup is plugged with crap?
     
  6. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    if that is the case would a motor flush work to remove all of that crap....otherwise I have to pull the motor
     
  7. did you fill the oil filter before you cranked it...if not it takes a little while to fill it....
     
  8. maybe the pickup tube fell off?
     
  9. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    maybe i'll try some gunk motor flush and if that does not work out she goes
     
  10. aaggie
    Joined: Nov 21, 2009
    Posts: 1,543

    aaggie
    ALLIANCE MEMBER

    If it has only been 8K since it was rebuilt I wonder where any sludge would have come from. It sounds more like a gallery plug was left out or a problem with the pump or pickup tube.
     
  11. Fogger
    Joined: Aug 18, 2007
    Posts: 1,192

    Fogger
    Member

    Are you getting oil to the rockers when using the preluber? If not pull the pan before anything else. Could be the oil pump pickup has fallen off. I wouldn't take a chance running it any longer.
     
  12. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    i am getting oil to the rockers.....slowly....it has got to be a pump related problem and i have to pull the motor to get the pan off....good news is I needed to freshen up the paint on the motor so....


    fun.......wow.......
     
  13. Dooley, if you don't find your issue after pulling the pan, plan on pulling the timing cover. Did you remove those 3 galley plugs for the rebuild and if so how did you reinstall them? If you used just press in cup plugs did you stake them? I'll walk you through the proper way to tap them if you like. After you remove the pan, try and get a measurement of how close the pick up was to the bottom of the pan. Hopefully the pick up is still in place too. It seems strange that oil would make its way up the push rods but not through the plastic oil line to the gauge, or is oil visable in the line now that it is going up to the rockers?.
     
  14. fiddy
    Joined: Sep 24, 2009
    Posts: 163

    fiddy
    Member

    Try adding an extra quart of oil to it. If the pressure picks up chances are your pickup has fallen off.
     
  15. Those 3 pressed in plugs should never (ever) be used on a major SBC overhaul.
    It takes a 1/4" NPT tap,,about 10 bucks for three 1/4 alum pipe plugs and about 30 minutes of your time.
    Its a little tricky though,,if the tap gets ran in too far it will block an oil passage.Not far enough & the plug wont engage the threads properly and/or the plug will be in the way of the cam sprocket.
    I have a trick way of doing this with pics if anyone is interested.
    Those pressed in plugs are "okay" but I kinda like something a little more positive when it comes to oil pressure.The holes should be threaded before the block ever goes to the jet cleaner/machinist.
    Theres also a pressed in plug above the rear main cap that should be looked at as well.
    Dumping more oil in is a great idea right now.
     
  16. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    I can only get oil through the clear tube, and thus to the tops of the rockers at 2000 rpm or more anyrhig less and there is no movement through the tube and 0 readng on the guage.
     
  17. Dooley, listen to me if you need to tap and replace the 3 front oil galley plugs, do NOT use "aluminum" pipe plugs.

    Furthermore, there are MILLIONS of SBC, stock or mild rebuilds that have staked in galley plugs and they won't come out done properly, period. Does the other poster want you to completely tear down the engine just so you can tap the three holes, when they have been staked sucessfully for over 50 years?

    We engine builders also have a remedy for proper thread engagement in shallow depth pipe plug holes.
     
  18. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    i wil check the timing cover is I do not find something in the pan.

    I am just a tad higher than the full mark, and have never had to run over to get oil pressure
     
  19. Dyce
    Joined: Sep 12, 2006
    Posts: 1,581

    Dyce
    Member

    Did you add the STP to the engine with the oil? You should add the STP to the oil with the engine hot and running so it mixes good. If the stp hits the filter unmixed it could plug it up.
     
  20. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    i added stp to the engine when dry before the oil
     
  21. Dyce
    Joined: Sep 12, 2006
    Posts: 1,581

    Dyce
    Member

    I'd try a new filter. It's cheap and easy.
     
  22. Pardon if someone asked this already. Did the pick-up tube get welded on ?
     
  23. 65elcaminos
    Joined: Apr 8, 2010
    Posts: 3

    65elcaminos
    Member
    from kc mo

    you might check the oil galley plug in the rear of the block, if it is run in too far it will restrict the oil from getting to the gage and rockers.
     
  24. Commish
    Joined: Jan 9, 2010
    Posts: 374

    Commish
    Member
    from NW Ok

    Dooley, that is scary, added that way it is setting in the bottom of the pan, if you have been doing this on previous changes since the rebuild, then that is probably your problem, if not then it is something else. I would not use STP in anything but a worn out engine that I was trying to extend the life of.
     
  25. swanwaco32
    Joined: Feb 7, 2005
    Posts: 98

    swanwaco32
    ALLIANCE MEMBER

    Had one break a rear main cap bolt and press dropped. pulled oil pan and found the head of the bolt.
     
  26. Rex_A_Lott
    Joined: Feb 5, 2007
    Posts: 362

    Rex_A_Lott
    ALLIANCE MEMBER

    I'm guessing "blue glue" in the strainer. Several good suggestions...no way around pulling the pan, maybe you'll get lucky and its something simple. Good Luck.
     
  27. If the new STP is anything like the old STP, this could be an issue. I've seen it coagulate when mixed with other oil additives, the oil pick up looked like wax was poured into it.

    I've seen this too in small amounts (squeezed out from gasket installation), a possibility.

    Pulling the pan is the only way you'll see what's up. The pickup tube is probably still on, but rotated enough to have a trace of pressure, got $2 riding on this theory.. any takers?

    Bob
     
  28. Dooley
    Joined: May 29, 2002
    Posts: 1,820

    Dooley
    Member
    from Buffalo NY

    thanks guys....i used the stp for the zinc....not sure if I added it first before or not...
    I'll need to find time to pull her out and we'll see what I find....
     
  29. aaggie
    Joined: Nov 21, 2009
    Posts: 1,543

    aaggie
    ALLIANCE MEMBER

    Just so you know, if you use a screwdriver blade chucked in a drill to prime the oil pump it will only prime one side of the engine. The distributor body seals to the block and sends the oil to both galleries. Thats why the priming tools you buy are shaped like distributor shafts. You may be adding an unwanted variable to your troubleshouting.
     
  30. bjinatj
    Joined: Jun 24, 2008
    Posts: 390

    bjinatj
    Member

    You put 20w50 in a motor with only 8k miles?
     

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