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Thread: Blocking off emissions / exahust sytem questions

  1. #1
    Join Date
    Jun 2009
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    17

    Default Blocking off emissions / exahust sytem questions

    My scout is titled as historic so emissions issues aren't an issue.

    My 1980 345 scout that I just got has a seized emissions pump, no belt, and no hoses. It'd be costly to get it set back right, so I was hoping I could just plug the emissions manifold holes on the exhaust manifold, but I am not sure how bad (if at all) that would be for the engine.

    Also, I was wondering what kind of exahust systems there are from the manifold back. Do people just go with a custom exhaust with flowmasters or something?

    Thanks!
    6/16/2009 - Bought my 1980 Traveler (345A)!

  2. #2
    Join Date
    Jun 2009
    Location
    Hurlburt Field, FL
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    495

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    Can't tell you if you can plug off the smog pump or not, but I can say that my last '79 didn't have a smog pump at all. They run fine without it if you can figure out how to get rid of it. And for exhaust I've always just had a shop put on true duals with no catalytic converter (most shops will let you get away with it if it doesn't have one when you bring it in, so just cut your old one out).

  3. #3
    Join Date
    Jun 2009
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    Unfortunately the '80 scouts were not dual exhaust. I'd want to see some good under-body pics of a 79 to compare and figure out if I could do dual. I'd definitely like to do duals, but it'd probably be a bit more complicated.

    I didn't know if the EGR stuff tied into the carb.
    6/16/2009 - Bought my 1980 Traveler (345A)!

  4. #4
    Join Date
    Jun 2009
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    Hurlburt Field, FL
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    Yeah, I know most of them weren't dual exhaust. A good shop will be able to do it anyway though. I think the most I ever paid for a full job was 250.00 because you just have them turn the pipes down from the manifolds and come straight back running right along the frame rails, and make a custom hangar right before the rear axle, and turn them out. I think the smog pumps were more for emissions than anything. There may be more to them than that, but I don't know.

  5. #5
    Join Date
    Feb 2009
    Location
    Aiken, SC
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    2,423

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    The smog pumps were there to pump air into the exhaust so that unburned fuel would have oxygen and burn the fuel the rest of the way. Purely a smog thing, mandated equipment, very poor legislation. Nissan finally showed that spark plugs on the exhaust stroke were just as effective, but it required 8 plugs on a 4 cylinder engine. Right after that, fuel injection started to become more common, and the smog pumps went away.

    The smog equipment can be bypassed. Just tune without it. If you have your heart set on just getting rid of it, you can get plugs for the holes in the heads. IH used to sell them, but they have a standard thread. I forget which size, but you can match them up. It is possible you will get a little bit of whistle from the odd surface where the tubes previously extended into the head, once you plug the holes. You can insert the plugs and grind it all smooth, or you can insert the plugs, mark them, remove them, and grind them down and re-insert them. This method requires that you don't mix them up after you mark them. Either way, you pull the exhaust manifold to do all this, so new gaskets are needed, as well as new donuts (because you have to be an idiot to not replace them when you pull the manifolds).
    Allan E.
    Curmudgeon Extraordinaire
    Charter Member, Old Hippie IH Club
    Old fashioned binder freak

  6. #6
    Join Date
    Jun 2009
    Posts
    17

    Default

    What about the louver on the passenger side manifold? I don't like taking stuff out that I don't understand the consequences first.
    6/16/2009 - Bought my 1980 Traveler (345A)!

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