Oil in distributor

Discussion in 'Troubleshooting & Diagnosis' started by GPN, Jul 3, 2020.

  1. GPN

    GPN Veteran Member

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    Does anyone know why oil would pool in my distributor-up where the rotor sits—not below at bottom of shaft. It is a little hard to see from this pic—but is right there below the wires
     

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  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    What brand distributor?

    There’s a seal (or sealed bearing) at the top of the shaft which is supposed to keep the oil out of the upper distributor area.
     
  3. GPN

    GPN Veteran Member

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    I’m trying to identify distributor. There are a couple of numbers in it, but no brand name.
    This is a newer crate motor with less than 2000 miles.
     
  4. Camaro Tim01

    Camaro Tim01 Veteran Member

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    Should all be the same size ....
    mark where rotor is to base, where rotor is to engine block, yank it out, knock the pin out of gear, pull shaft out look at top of housing and change the seal there. If there's any O rings on the shaft itself, change those too.... any autoparts store should have those parts.
     
  5. GPN

    GPN Veteran Member

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    Thank you....sure seems like an unusual issue. Even the shop that installed my engine had never see oil pooling there
     
  6. Camaro Tim01

    Camaro Tim01 Veteran Member

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    it is but manufacturing mistakes and defects do happen...
    once shaft is out inspect the old seal and note how much if any of the rubber is missing from it, might have broken off and fallen into the engine...could get stuck on your oil pick up screen or possibly block an oil passage.
    Watch oil pressure if you have gauge after you fix it for any erratic needle movement ( piece moving around )or lower than normal readings ( blockage).
    If you ever drop the pan, look for the seal pieces and remove them
     
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  7. GPN

    GPN Veteran Member

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    Thanks. Engine is out now, so I should be able to give thorough inspection
     
  8. Rocky Rotella

    Rocky Rotella New Member

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    It looks to me like it's a typical HEI. Typically, there aren't any rubber seals or sealed bearings in an HEI unless it's been redesigned by a given aftermarket manufacturer. In an HEI, the main shaft rides on two bushings pressed into the housing--one upper and one lower. The lower bearing is lubricated by oil splash in the and the housing body is fluted internally (around the bushing) to allow oil drain back. In a GM HEI, the upper bushing is surrounded by a well packed with grease that liquefies at operating temp to lubricate the shaft. Many modern reproductions have no grease backed in there and the upper bushing has no provisions to pass lubrication.

    In my opinion, if an HEI has oil puddled under the cap, I'd suspect a windage and/or pressure issue inside the crankcase. The crankcase pressure is escaping through the operating tolerance in the HEI bushing/shaft design and its taking oil mist with it. I'd strongly suggest checking that your PCV system is operating properly and moves enough volume.
     
  9. hd_cat

    hd_cat Member

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    Sounds like positive crankcase pressure, might want to check PCV system and add a breather to the valve cover. I recently saw a comment recommending against use of aftermarket PCV valves, I just bought a Delco for the 377 in the '73.
     
  10. GPN

    GPN Veteran Member

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    thank you
     

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