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How to de-smog an 74 with F engine..

Discussion in '40- & 55-Series Tech' started by 74cruiserintexas, Jan 1, 2003.

  1. 74cruiserintexas

    74cruiserintexas

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    What all can be removed as far as vacuum lines?? What do you do with the fittings where the air injection rail went into each cylinder?? Has anyone had any problems with removing the smog stuff??
     
  2. Gumby

    Gumby Supamod Staff Member s-Moderator

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    You can pull everythng but the EGR and the vacuum advance for the distributer. The tubes in the head are a pipe thread. 1/4 NPT, I think, but I would take the rail into the hardware store to match up for sure. Buy 6 plugs and lock-tight them in there.
     
  3. rick_d

    rick_d

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    Please, do the cruiser community a favor and keep the smog equipment together and sell it off as a package. 1974 F's (pass side filter) have somewhat unique systems and many owners in smog states (ala California) really need this equipment.

    I would use anti sieze in the air rail plugs, just snug them down. the Allen head ones are better than square head if you can find them.
     
  4. woody

    woody Internet Fireman Staff Member

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    Home Depot has brass allen plugs that would work nicely - I used a few when I pulled Vacuum stuff off my TBI intake this week.

    And do keep that stuff for another buyer - or if you ever sell the rig and the buyer is in a smog-required zone.

    And check your local stuff too....not all areas are sniffer only, some require underhood inspection.
     
  5. 74cruiserintexas

    74cruiserintexas

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    Thanks guys....all of the vacuum lines on the stock carb...how many are still needed?? Or would i need to change carbs??
     
  6. Gumby

    Gumby Supamod Staff Member s-Moderator

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    NO need to change carbs. Buy a package of vac line plugs. You'll like them better than a chunk of vac line with a bolt in the end. If you don't lock-tite the plugs in, be sure to carry a couple extra. I had problems with them coming loose.
     
  7. 74cruiserintexas

    74cruiserintexas

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    So all of the points on the carb that have vacuum lines I just need to cap off?? Or do any of them still need vacuum??
     
  8. woody

    woody Internet Fireman Staff Member

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    you'll trace each vacuum line thru....there may be 1-2 that are kept....

    does the Jim Chenoweth diagrams in the tech links show what to keep and not keep??? <hint hint> lol
     
  9. 74cruiserintexas

    74cruiserintexas

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    Tell me if this sounds right....need 1 vacuum line from intake to distrubutor, one line from intake to throttle position diaphragm on carb, one line from intake to charcoal canister. From the Haynes manual and the diagram on here that is what it looks like but I guess I need reassurance. Thanks...
     
  10. PHAT MAX

    PHAT MAX

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    well, when we got our 74 (with 76 2f in it) I just said, well that doesnt need to be there. neither does that, oh and that too. I knew NOTHING about cruisers and it still runs fine. i dont think they are that picky :D

    i took off the AIR rail and put in some pipe plugs we had laying around (actually dad got some more from work) they just screw right in. we didnt even loctite them and so far no leaks. we are doing the same thing on our 78. IIRC, i kept the dist vacuum advance, not the retard (mech told me retard is for retards) and kept the charcoal canister. also removed the air pump and plugged the hole for that on the air cleaner.

    hth,
    Max
     
  11. fresno-lc

    fresno-lc

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    you can take out the charcol canester too
     
  12. Gumby

    Gumby Supamod Staff Member s-Moderator

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    I would keep the EGR too. It cools the piston heads and helps with detonation.
     
  13. onesprung60

    onesprung60

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    Don't get too happy pulling everything off until you know exactly what it was suppossed to do. Unless you are using an aftermarket carb. you most likely want to keep the evaporative emissions system, choke breaker, choke opener, positive crankcase ventilation and high altitude compensation valve (if equipped). Remember that many of the emissions controls on the 2F lean out the carb. so you will need to re-jet and readjust the carb when you are finished. If you have a grainger supply nearby the part number for the air injection plugs is #3P878, these ones are the inverted hex head and are made of brass, they fit very well and give the head a nice finished look.