Distributor vacuum line quandry

Discussion in '40- & 55-Series Tech' started by Spencer, Sep 25, 2003.

  1. Spencer

    Spencer

    Messages:
    11
    I have a 1978 FJ40 with stock 2F engine. My distributor is a "For USA/semi-transistorized" per the diagrams in the Toyota and Haynes repair manuals. This distributor has "Vacuum Retarder" with a vacuum line nipple on each side of the retarder diaphram. When I bought the truck, all of the pollution stuff was removed and these two lines were capped as well as the vacuum lines on the carb. The engine starts and runs fine, but when I accelerate, there is a pause in the power and then a surge at full pedal. I have recently replaced the plugs, coil and ignition wires. Questions:

    1. I cannot find any diagrams in the manuals that I have available that show how to connect the vacuum lines. I have run a vacuum line from a vacuum nipple on the carb base to one side of the distributor "retarder", leaving the other vacuum nipple plugged, with no noticable improvement in performance. Switching the vacuum line to the other side of the retarder does not change anything. Does this distributor need a vacuum retard(advance) to operate properly? If so how can I make it work?
    2. Is this distributor problem likely the cause of the "flat spot" in the engin power.
    3. I also have a "parts" FJ40 of the same (1978) year. It has an Except for USA/Conventional" distributor with a vacuum retarder that has a single vacuum nipple on the outer side of the vacuum advance diaphram. Would I be better off using this distributor and connecting the retarder vacuum nipple to a vacuum nipple in the base of the carb.
    4. Any other suggestions.
  2. Landpimp

    Landpimp

    Messages:
    13,118
    Location:
    PNW
    I'm not great with this stuff but, with all the emisions stuff off there is no need to retard. If anything use the other dizzy and just hook up the advance.

    I would say yes you need advance to make what you have work. Retard is gonna cut power not give you more. Is this the cause of your problem.....I don't know :(

    I'm SURE someone who knows what there talking about will chime in.

    John H
  3. spotcruiser

    spotcruiser Geezer SILVER Star

    Messages:
    2,408
    Location:
    Western WA
    Spencer,
    Spark retard is a smog control function. As John said, you want spark advance. The stock carb and distributor are totally unsuited (in the stock configuration) for proper operation without the smog gear.

    You can't get proper vacuum from the stock carb, because the vacuum ports are not drilled in the correct location. Contact Jim Chenoweth ( FJ40Jim@aol.com ) about modifying your carb for vacuum advance.

    It sounds like you have a Federal spec distributor with retard for smog and advance for High Altitude (vac hose on each side of the bellows). Even if you get proper vac to the advance port, the advance won't be of the magnitude a properly designed vac advance system would have. I think Jim C. can also rework your distributor.

    Contact Jim. Tell him your situation and ask his opinion. He's a goldmine of information, he's very generous with the information, and he'll tell you straight up. His prices seem pretty expensive, but after he's done you'll have a vehicle that operates the way you want it to and you'll only have to pay for it once.

    Just my opinion. HTH.
    Todd Bull.

    P.S. If you need info to connect stuff stock, I have all of the diagrams for '78 and I have a one-owner '78 as a reference. :)
  4. dd113

    dd113 Supporting Vendor

    Messages:
    2,838
    Vac retard does not help much but it does help smog issues. I would cap the closer to the dist of the 2 ports ,that should be the retard, then run the Hi altitude port, the one furthur out, to the carb. You will run better but not perfect. As the other post said, contact Jim C for serious info.
  5. Spencer

    Spencer

    Messages:
    11
    I got pretty much the same advice from SOR Tech Service. According to SOR, I can run it like it is or, to get true vacuum advance, I would have to get a Toyota vacuum advance distributor (which I think by extra parts vehicle has) and a connect to a carburator with a "ported vacuum" which the stock USA carbs have. It sounds like I need to get someone to modify my carburator for a vacuum advance. I emailed Jim Chenoweth per Todd' suggestion, but have yet to get a reply.

    Any ideas?

    Do the Weber carbs have a "ported Vacuum" port?
  6. Spencer

    Spencer

    Messages:
    11
    Excuse me - the stock USA carbs do not have "ported Vacuum" per SOR Tech, only manifold vacuum, which will not work for the vacuum advance distributors.

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