Rebuilt engine still using oil

Discussion in 'Small Block Tech' started by 69WILD, Sep 25, 2022.

  1. 69WILD

    69WILD Ron

    Yes. Probably around 10.5 compression. Definitely may be running rich.

    I will check blow by at idle later tonight.

    Thanks again for the insight. ;)
     
  2. 69WILD

    69WILD Ron

    I removed the breather hose from left valve cover before I shut engine down for the night. I plugged the valve cover grommet with my thumb while idling 600-700rpm and feel quite a bit of suction/vacuum. I can hear the sucking noise when I pull my thumb off.
     
  3. 72gs4spd

    72gs4spd Well-Known Member

    I would do the same test while disconnecting/ plugging the PCV valve. If you still have vacuum I would thing intake gasket bad.
     
    69WILD likes this.
  4. Jim Nichols

    Jim Nichols Well-Known Member

    Did you try retorquing the intake?
     
  5. sean Buick 76

    sean Buick 76 Buick Nut

    Also try using a propane torch without lighting it to poke around the intake and if the engine revs up you have an intake leak.
     
  6. 69WILD

    69WILD Ron

    I will check those items again. Thanks everyone :)
     
  7. Stevem

    Stevem Well-Known Member

    Just note that while a propane test is easy and can be very helpful, in your case if oil is getting sucked into however many intake ports that may be leaking , that sucking is taking place where a propane test will serve no purpose.

    I really think your at the point now of getting what you need to either do a leak down test, or pull the intake to see what’s taking place.
     
    sean Buick 76 likes this.
  8. 69WILD

    69WILD Ron

    I plugged the pcv and removed the valve cover vent. No vacuum. Smoke but not a lot of pressure if I plug the hole. Smokey pulses.

    I don't notice any smoke out exhaust.

    Seems like it might be normal at idle?
     

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    Last edited: Sep 28, 2022
  9. 69WILD

    69WILD Ron

    Thinking maybe install a catch can on the pcv hose to see if a lot of oil is escaping?
     
  10. Stevem

    Stevem Well-Known Member

    Doing that will not guide you towards nailing down what the issue is of which I see two that could be the cause.

    If you do not want to rent or by a leak down tester to rule out rings, then I say it's high time to yank the intake manifold
     
    Max Damage likes this.
  11. 69WILD

    69WILD Ron

    Ok I'll try to do a leakdown test next. Thanks for your thoughts. :D
     
  12. Stevem

    Stevem Well-Known Member

    Just lets review what's happening here so you don't possibly go spending money you don't need to.

    If all 8 plugs are showing the same basic level of being black & oily, then do the leak down test first.
    If some plugs are far more oiled down then I would pull the Intake off first to look for gasket vacuum leaks.
     
  13. 69WILD

    69WILD Ron

    Yes. Thanks again.
    I posted pictures of the plugs on post #7 with the compression test results. The plugs seem fairly uniform. A bit black at base and a VERY slight bit of oil on threads only. The picture of plug #2 (the lowest) may be slightly blacker but they don't seem to me like they are seeing a quart every 200 mi. And no noticeably smoke out exhaust. No misfiring.

    I may try the loaner compression tester from autozone and see if I can add a port for my compressor. Harbor freight wants $85 for a leakdown tester. o_O
     

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    Mark Demko likes this.
  14. Mark Demko

    Mark Demko Well-Known Member

    Are you needing a leak down tester or a compression tester? I’m confusedo_O
    If you need a leak down tester, I would buy one and add it to your tools, you’ll find yourself using it quite often for diagnoses. It’s actually more useful than a compression tester.
     
  15. 69WILD

    69WILD Ron

    I need a leakdown tester to diagnose the rings sealing. But if it confirms they haven't seated yet I'm not ready to tear the engine apart. So maybe there is no point. :(
     
    Last edited: Sep 30, 2022
    Mark Demko likes this.
  16. Mark Demko

    Mark Demko Well-Known Member

    Rings seal the first few miles, if they haven’t seated by now they’re not going too
     
  17. Fox's Den

    Fox's Den 355Xrs

    there is too much fuel change what ever you have to change in that Q-jet to cut the fuel down the plugs are black too much fuel. If you bare washing down walls with too much fuel then it will never seal. Then you guys put in those extended tip plugs and up the timing, there's a disaster waiting to happen. I run 32* total timing with non extented tip NGK plugs 5 gal race gas with 15 gal of 93 and my plugs are brown no issues no oil burning but it will smoke some from sitting and probably leaks down the valve guides but after a trip down the track it is all cleaned up. Highway does same thing.

    Do the leakdown test, I just did mine and after 25+ years I still get over 90% with 8% leakage at the worst cylinder with most at 5-6% leakage my compression test had them all past 185
     
    TrunkMonkey, 70skylark350 and 69WILD like this.
  18. Jim Nichols

    Jim Nichols Well-Known Member

  19. 69WILD

    69WILD Ron

    Leakdown tester arrives this afternoon from Amazon.

    Picture of #2 spark plug pulled again this morning.
     

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  20. 69WILD

    69WILD Ron

    Oil still looks pretty decent after 1500+ mi. No gas smell.
     

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