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can bad vacuum booster cause oil burbning?

Discussion in 'The Hokey Ass Message Board' started by freebird101, Nov 29, 2009.

  1. freebird101
    Joined: Feb 13, 2009
    Posts: 1,203


    My cousin just got a '51 Pontiac with a flathead straight 8...... while we were driving we smelt burning oil and were wondering if it might be a bad vacuum booster may have caused it. can any one help us find out.
  2. Edelbroke
    Joined: Dec 12, 2008
    Posts: 767


    If you could smell it while you were driving I would think the oil burning would be coming right off the motor and through thr firewall. Leaky valve cover?
  3. Orn
    Joined: Jul 17, 2005
    Posts: 1,035


    If you have a double action fuel pump with a bad vacuum section it can burn oil.
  4. bobwop
    Joined: Jan 13, 2008
    Posts: 6,079


    blow by out the breather and through the firewall. Add a quart of transmission fluid, drive it for 15 minutes, change oil and add a quart of Lucas. Might do the trick
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  5. fearnoevo
    Joined: Nov 28, 2009
    Posts: 218

    from Iowa

    The breather on my '64 Bel Air wagon used to vent down by the exhaust pipe and stink to high heaven. At 200K miles the valve seals were more than a little worn. So it vented a lot. 12 feet of stolen garden hose some where in Illinois at 2 in the morning fixed it nicely, and it only took 2 cases of oil to get to Clarksville, Tn for the Nationals that year.

    Thanks to a Sunday morning monsoon, half the field went home and we qualified as 2nd alternate our first time to the Nats. We were unemployed and didn't have to be to work on Monday

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  6. Maybe slightly off the subject but possibly a little bit related-

    The crankcase breathers on my Studes gave off that oil smell too until I put hoses on them and ran them a different way that moved the openings far away from the engine or passenger area.

    When you do that, be careful that you don't slow down or stop the venting of the crankcase, or increase it so much that you start pulling the heavy oil vapors out.

    On my pickup I simply extended the lower road tube farther back past the cab, and made sure the oil-breather/filler-cap with the filter mesh was somewhat in line with the opening of the air cleaner snorkle.

    That way all the smells were either burned in the engine, or let out away from the cabin area. Be careful not to make a vacuum at the "intake" end of the vent system or you could get reverse flow without the benefit of the exit-baffles that make the oil droplets stay in the crankcase. Engines normally have baffles or long pathways to help the oil particles drop out before the fumes exit the road tube. If it flows the wrong way, a lot of oil often goes with it because the other end is not usually baffled.

    My Hawk ended up somewhat duplicating some of the mid-60's cars PCV systems. The engine was completely sealed, and all vapors vented though filters and burned in the engine much like a modern engine.

    No more oil or exhaust smells.

    Sometime back in the early 50's the Willys company did experiments with burning the crankcase vapors in their engines. Their reasearch said that cylinder wall wear was somewhat reduced when the engines burned their own crankcase vapors.
    A good idea that took a while to catch on.
  7. flynbrian48
    Joined: Mar 10, 2008
    Posts: 6,182


    Uh, your '51 Pontiac has a vacume booster? Where? More than likely nowhere, unless somebody has added power brakes, cause these don't have boosted brakes from the General. Probably the old girl has enough blowby that you're smelling crankcase fumes. You might, if it's not terminally tired, plumb a PCV valve in rather than the road draft tube, but more than likely, it really wants new rings for Christmas...

    Oh, a bad vacume modulator on a trans can cause trans fluid to get sucked up and lay down clouds of blue smoke, but you don't have one of those either.
  8. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    Member Emeritus

    Just got it? Did you degrease the engine yet? If it's like most of the old cars that I have picked up, it will have lots of gunk and caked on grease that has accumulated over the years. Some engine degreaser and a few hours with a pressure washer can reduce some of the smells. The breathers are often filled with years of grease. When that grease gets warm it will smell. Cleaning all the caked grease and oil spills can do wonders.

    Don't panic if you see wisps of smoke coming from the breather when it is idling in the driveway. That is normal for a car from that era. When the car is moving those wisps will get sucked out through the road draft tube underneath and not go into the cabin.
  9. Kencary
    Joined: Dec 17, 2009
    Posts: 9

    from Cary, NC

    Thanks for posting this to HAMB.

    All the smoke stopped after a tank of new gas and a little driving.

    As you and I suspected, the smoke was not oil as it did not smell like oil.

    I think the oil smell when you are I were in the car was just spilled oil on the motor somewhere. Maybe the original owner spilled some when filling the oil bath air cleaner.

    All is fine now that the car is here in NC. I can floor it up a hill without even a hint of smoke once it is warked up.


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