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318 woes..please help

Discussion in 'The Hokey Ass Message Board' started by rev106, Jan 27, 2007.

  1. rev106
    Joined: Dec 13, 2006
    Posts: 542


    Here’s my problem: The motor in my van will idle rough for a few seconds and then smooth it’s self out and sound bitchin’. Give it a little gas and it will miss a little and then run rough again, and then smooth its self out again. My friend that’s helping me has been a hot-rodder for 50 years and has never seen anything like it. Any suggestions would be helpful.

    318 motor, 1966 dodge van
    new manifold (edelbrock), rebuilt carb (holley 4 barrel), new distributor. It has headers if that matters?

    My friend is convinced the problem is in the motor. I’m pretty ignorant of what he’s trying to tackle, so any pointers would be nice.

    Thanks for your time.

    Paul in So Cal
  2. Shagrat
    Joined: Dec 18, 2006
    Posts: 212


    I'd search for vacuum leaks first.
    If you can rule out the carb, that helps a lot. Swap on a carb that works good from another car. If the problem's still there, then it's on to ignition.
    If it's still got the point's set-up, I would recomend updating to electronic in any event. Mopar-Performance makes a kit that has the dist.,wiring,ballast-resistor and orange box with all the neccesary instructions.
  3. timing chain/ gears

    5 dodge vans 71-87...
    always what it has been after chasin down the ignition stuff
  4. If the fan is a solid fan and not a clutch fan grab it, and rock the engine back and forth. You should be able to FEEL the slop in the chain.
    I've owned dozens of small blocks, never had one skip a tooth, although the factory nylon covered upper gears can contribute to a scenario where it is possible.
    Is the dwell at 30 degrees? About .017 or so for a gap...?
    What's the timing set at?
    Accelerator pump has a good shot? Have you looked down the carb and seen if the accelerator pump is working??
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  5. k9racer
    Joined: Jan 20, 2003
    Posts: 3,117


    This morning I found the same problem on a neighbors 360 carbed truck.. The fix.. Tighten the bolts that hold the intake manifold..I hope this helps.
  6. Could be a timing problem, but I'd check for vacuum leaks first.

  7. recardo
    Joined: Aug 31, 2006
    Posts: 833

    from Winslow

    Change all the rubber vacuum lines, swap carbs, then take the manifold back off, clean the surfaces real good (maybe check the surfaces for flatness) and reinstall it.

    Torque the manifold on, inside bolts to outside bolts. Don't go by feel. I think 30 pounds is pretty common. More isn't better.
  8. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,536


    If it is a 66 318 and still has the original timing chain and gears, I would start there. Those nylon cam gears devolope a lot of slop as does the chain itself. If when the timing light is on the marks with the engine running there is any vairation of the timing marks, that indicates slop in the gears/chain. Some of the biggest performance issures of stock 318s are the sloppy timing chains/gears, small carbs, and choked exhaust. Gene
  9. Was the motor running fine before the intake and carburetor change? If so, this is why I suspect a vacuum leak. I would start here, then check out the timing.

    I'm sure the motor probably could withstand a new chain and gears if they've never been replaced, but they may not necessarily be the reason the motor is acting up.

  10. Abomination
    Joined: Oct 5, 2006
    Posts: 6,692


    Is this a Poly 318? '66 was the last year for it.

    Or did someone put a '67+ LA 318 in there?

  11. rev106
    Joined: Dec 13, 2006
    Posts: 542


    I'm going to guess it's the og motor, it's greasy enough. So far most people have said carb or timing chain. I guess I'll look into those and see what turns up.

  12. Abomination
    Joined: Oct 5, 2006
    Posts: 6,692


    A Poly 318 has scalloped valve covers, like this:

    For more info, feel free to browse Tha Polyspherical Engine Association website:

    Or stop by the 318 Poly Yahoo Group:

    Or the 318 Poly Forum:,6.0.html

    I've inherited webmaster duties at the Polyspherical Engine Association, and have recently updated the Business Directory in an attempt to make hard to find parts a lot easier to find!


  13. set your timeing mark on 0 then pull the dist cap off.
    rotate the motor with a socket or by hand and see how much the timing mark it off when the dist starts to turn.

    my bet is timeing chain also.

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