VACUUM PUMP FOR HEMI?

Engine, Trans & Driveline

  1. eightstackhemi

    eightstackhemi FBBO Gold Member FBBO Gold Member

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    Any suggestions for adding a vacuum pump to my 472" Hemi to reduce pressure in the crankcase? I have a rear main leak that I think will clear up if I add one. I hope!
    I'm running synthetic VR1, but may go back to conventional VR1, too.
    What about used units, salvage yard or wherever, or new?
     
  2. PurpleBeeper

    PurpleBeeper Well-Known Member

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    What about those race "catch can" setups where you run a high temp hose into the collectors of the headers? I've never run one, so I don't know jack about them, but they look simple enough. I'm betting you will have to replace that rear main seal though...maybe it will save the next one
     
  3. snakeoil24

    snakeoil24 FBBO Gold Member FBBO Gold Member

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    The vacuum pump will not do anything to stop your leak. Infact it will harm the ring seal quickly. Instead order the replacement seal retainer from Indy which is a machined replacement with strip seals. Install it and say good by to your issue.
     
  4. Hemirunner

    Hemirunner Well-Known Member

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    Huh? Running a crankcase vac pump will improve ring seal almost 100% of the time. Depending on the nature of his rear main seal leak, it may or may not have any impact on it. If it’s an old MP crate engine, the rings may have never sealed in the first place and the resuting blow by is pushing oil out the rear main. There’s also a dozen other things that could cause it as well. As to the pan-o-vac solution mentioned above, those don’t work too well with full exhaust. If you want to run a vacuum pump on the street, the GZ Motorsports versions are street friendly.
     
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    • snakeoil24

      snakeoil24 FBBO Gold Member FBBO Gold Member

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      Vac pumps for drag racing are fine. But street cars just dont seal well. Hemis all have issues with valve seals and poor seal on crank seal. The Indy seal will correct this.
       
    • Hemirunner

      Hemirunner Well-Known Member

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      Maybe in stock form with cheap umbrella seals and loose iron guides. A well built engine regardless of type doesn’t have these issues. The engine won’t know if it’s in a race car or a street car.
       
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      • coloradodave

        coloradodave FBBO Gold Member FBBO Gold Member

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        But, but Greg's (GZ Motorsports) vacuum pumps are made in, GULP, California and everyone knows nothing good comes out of our state...
         
      • eightstackhemi

        eightstackhemi FBBO Gold Member FBBO Gold Member

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        I have an evac system that runs to breathers on both rocker covers, but that's not a 'catch can' setup. It does its job, but doesn't take care of all that crankcase pressure.
         
      • eightstackhemi

        eightstackhemi FBBO Gold Member FBBO Gold Member

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        The block is a 1999 Series Iron Hi Nickel Alloy 426 MP block that is built to 472". It is not a street motor, but a race motor w/12.5:1 CR and driven on the street once in a while to shows & cruise-ins. Currently, it runs 814hp/684tq on F&L's SP3 - 113 octane fuel.
         
      • Hemirunner

        Hemirunner Well-Known Member

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        Sounds like a fun one. How quick is it?
         
      • PurpleBeeper

        PurpleBeeper Well-Known Member

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        Holy blow-by Batman! Still blowing out rear main seals with an evac system? Wow. Yeah, maybe you do need some type of vacuum pump (& a new rear main seal). Are you constantly blowing out valve cover, timing cover & other gaskets too? Maybe your rings never seated like the other member mentioned?
         
      • eightstackhemi

        eightstackhemi FBBO Gold Member FBBO Gold Member

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        The leak is not massive, just drips after running it and sitting in garage. Doesnt lose much, just annoying. Sometimes, drips don't show up until the next afternoon. Ugh!
        Since built it probably has no more than 600 miles on the car.
        The car does NOT have an oil leak anywhere else on the motor! Dry as a bone!
         
      • eightstackhemi

        eightstackhemi FBBO Gold Member FBBO Gold Member

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        The original and only owner (and builder) of the car had it at the drag strip in Pamona ONLY ONCE back in 2005 right after the car was built. At the time, it was equipped with a 4000 stall & 4.56 gears & a pair of D-2 Eagles. Made the pass - got loose at 1100ft and lifted. Got the time slip and it read 9.96 et @ 139.62 mph.
         
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        • 2quick

          2quick FBBO Gold Member FBBO Gold Member

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          I'm running a Moroso new style vac pump on the street for the same reason, Trying to keep leaks under control. I'm running a BCR Girdle and windage tray so lots of stuff going on around the pan gasket. Now I just have to figure out how to mount the dam thing.
           
        • Ranger16

          Ranger16 Well-Known Member

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          Are you running a PCV? If so, wouldn't repaceing the intake filter with an oil fill cap on the intake side valve cover accomplish the same thing? Not sure I'd recommend that, but I suspect it would accomplish what you want. That said, if you ARE running PCV, you'd probably have to eliminate it in order to create a vacuum.
           
        • not so famous bob

          not so famous bob Well-Known Member

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          I had two 426 hemi`s back in the day. Raced one for 14 yrs., the other was a street car I rebuilt, neither one ever had a rear main leak. I did have to use kotex`s one week end for a front pump seal leak. It had to be changed every run, but worked, we won that race . Everyone said it was on the rag ! no brag, just fact ,.
          Vacuum pumps will work if set up right. Can u say, bad ring seal ?
           
        • 6PKRTSE

          6PKRTSE Well-Known Member

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          I have the Moroso 4 vane on my Hemi.

          20160507_120139 (002).jpg 20160429_111243 (002).jpg
           
        • eightstackhemi

          eightstackhemi FBBO Gold Member FBBO Gold Member

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          Good question, but No PCV valve on it!
           
        • Ranger16

          Ranger16 Well-Known Member

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          In that case, maybe it would be cheaper and easier to simply add a PCV valve to one valve cover and leave the intake side alone or maybe even eliminate the valve itself and just run the vacuum line off of the carb with no PCV valve for full time vacuum. In theory, I would think that would solve your problem. Just a thought.
           
        • not so famous bob

          not so famous bob Well-Known Member

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          Would be HEll w/ a big backfire !!
           
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