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225 Intake - Plugging The Exhaust Ports To Carb Y/n

Discussion in 'Early CJ5 and CJ6 Tech' started by jwmckenzie, Feb 9, 2017.

  1. Feb 9, 2017
    jwmckenzie

    jwmckenzie Sponsor

    Boston, MA
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    Working on a '67 225 Dauntless, the intake manifold has two ports (5/16"holes) that bring exhaust to the base of the carburetor. The guy that re-built my carb suggested blocking them off.

    Assume this keeps the carb at the right temp to preheat the fuel/air mix, right?

    Thoughts? If you have blocked them off what did you use?

    Here is pic of the exhaust ports (at pencil tip) I am referring to.

    [​IMG]
     
  2. Feb 9, 2017
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2020 Sponsor 2019 Sponsor

    cordele, Ga.
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    Those two exhaust ports under the throttle base plate usually plug themselves with carbon after a while and become in-effective. If they are plugged now just leave them unless you live in extremely cold climate.
     
    47v6 and Twin2 like this.
  3. Feb 9, 2017
    n6ifp

    n6ifp Member 2019 Sponsor

    San Bruno/...
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    My local carb shop recommeded plugging them during my last visit with them. One reason he mentioned for plugging them was it took heat away from accelarator pump. He says since doing this he has had very little Acc pump problems on GMs with this setup. It doesn't seem to bother my warm up since doing that. It also saves on base studs from rusting out.
     
  4. Feb 9, 2017
    tarry99

    tarry99 Member

    Northern California
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    Find a two barrel gasket that is blank and does not have those two holes.............or make one.
    Check the OD of the holes and either resize or buy a small freeze plug and plug them.............or If you have a Lathe make a plug out of aluminum.
    or...........if you know someone that works in a foundry have them pour the holes after you block off the other side like I did in these V6 cylinder heads.

    [​IMG]
    [​IMG]
     
  5. Feb 9, 2017
    jwmckenzie

    jwmckenzie Sponsor

    Boston, MA
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    Thanks All.

    The holes are not plugged with carbon. By the time I got them cleaned out they were larger than 3/8. I was able to cut some threads using a 1/8 NPT (pipe thread), but not enough to hold a plug unless I JB Weld it in.

    Some worried about the JB Weld holding up at the exhaust temp.

    Will go look for freeze plugs after the snow is cleared tomorrow. Looks like Dorman has a 13/32" steel plug, that will work.
     
    Last edited: Feb 9, 2017
  6. Feb 9, 2017
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    I had a carb gasket that looked like exhaust manifold material that was made to cover those holes. It's been on there for years.
     
    Twin2 likes this.
  7. Feb 9, 2017
    BJHitson60

    BJHitson60 Member

    San Rafael, CA
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    Nov 20, 2009
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    I have always pulled the intake manifold and cleaned these holes out (and the ones in the heads as well). A real PITA. I agree you don't really need them unless living in a cold climate but it does help the engine and carb. warm up faster assuming your heat riser valve is working properly - not a bad thing IMHO...
     
    Keys5a likes this.
  8. Feb 10, 2017
    jeepcj

    jeepcj Member

    cincy, Ohio
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    My 327 intake manifold has same type of holes in it but are a tad smaller. PO plugged them with large screws and looks like he ground the heads of the screws flat as to not stick up. then as terry mentioned get a gasket that does not have the holes.
     
  9. Feb 18, 2017
    jwmckenzie

    jwmckenzie Sponsor

    Boston, MA
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    To close this out, I plugged them with 13/32 freeze plug, Dorman 555-001. Still looking for a gasket that covers these holes. FLAPS counter guys look like I am speaking a foreign language, wait, I may be.....
     
  10. Feb 19, 2017
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member 2019 Sponsor

    Tri-Cities WA
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    Rochester 2g Float
     
  11. Feb 21, 2017
    BJHitson60

    BJHitson60 Member

    San Rafael, CA
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    I am pretty sure that the NAPA carb. kit for the Rochester 2G comes with lots of extra base gaskets - including one that covers the two holes... You may want to check that out if you cannot find a single gasket that covers the holes.
     
  12. Feb 21, 2017
    jwmckenzie

    jwmckenzie Sponsor

    Boston, MA
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    I will check out NAPA tomorrow. Thanks.
     
  13. Mar 7, 2017
    jwmckenzie

    jwmckenzie Sponsor

    Boston, MA
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    Alright finally found the gasket. Fel-Pro 17820

    [​IMG]
     
    Beach66Bum and BJHitson60 like this.
  14. Apr 23, 2017
    Beach66Bum

    Beach66Bum ‘66 Tux 2020 Sponsor 2019 Sponsor

    Big Island on...
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    This is the gasket I need! Thanks for the pic!
     

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