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Help timing my truck

Discussion in 'Classic Dodge Trucks - Pre 1981' started by charm, Jul 8, 2019.

  1. charm

    charmMember

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    1975 Dodge D300 with 360

    The truck has issues. Lots of issues. I'm working my way through them though. This latest one involves the distributor, electronic, which appeared to have had some mechanical issues. Bought a new one, Spectra, from Amazon and installed it today. Set everything to TDC, and everything went smoothly. I expected some tweaking of the timing afterwards, but things are odd. It's not 180* out, since I can get the backfiring to stop adjusting the timing, but I can't get initial timing anywhere near 6* advance (I seem to recall that's the goal). I can get it to run pretty smooth, haven't tried driving it, with the vacuum advance connected, but without it (and the vacuum line plugged) it doesn't run well and the timing mark is nowhere to be found by the light.

    Any thoughts on things I can check? I thought about moving the plug wires one plug clockwise on the cap.



    Since somebody will ask, the big issue, I thought, was vapor lock. But I've isolated as much of the fuel line from heat as I can and it hasn't been that hot out. Also have a 1/2 inch phenolic riser under the carb (quadrajet, don't ask, long story). The carb is set up for a Chevy 350 and was recently rebuilt by somebody far better at than I am. Further research shows that issues with the distributor can present as vapor lock as can a failing fuel pump. The new fuel pump came today and I haven't installed it.
     
  2. 7mopar

    7moparWell-Known Member

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    Time it with the vacuum disconnected to 6* if that's what the timing spec. calls for. I would guess the vacuum is not ported correctly. It should be above the throttle plates. Vacuum advance should not start until about 1700 rpm. and be all in by 2800 rpm.
     
  3. 65 sporty

    65 sportyWell-Known Member

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    Pull #1 plug and bring it to TDC, use a long piece of wire and feel the top of the piston, have a helper roll the engine by hand with a bar and socket clockwise until the piston starts to go down, then counterclockwise until it comes back up and starts to go down again. Roll it clockwise again until the piston comes all the way up and check your TDC mark, it should be really close.
    Pull the distributor cap and see if the rotor tip is pointing to #1 terminal or is way off.
    When you had it running did it sound lazy(late timing) or did it run ok but would kick some( over advanced timing)?
     
  4. charm

    charmMember

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    TDC was set by removing the valve cover and ensuring that both exhaust and intake valves were closed while the #1 piston was at top of its throw...it was set to TDC. When at TDC, the timing mark was a hair advanced of 0, less than 1/2*. Rotor looks reasonably close to #1 plug, but that’s something I’ll triple check tomorrow.

    While it was running, it was lazy. Moving the distributor in either direction would either make it stumble and stall out or, in the other direction it would kinda buck, then stall out. So, while I could get it running, I couldn’t quite get better...if that makes sense.

    I would love to time it to 6* advanced if the timing mark we’re anywhere in view of the timing light. That, in a nut shell, is the problem. I can get it running, but the mark is so far away from the gauge, I can’t get it in view to adjust to 6* advanced. I’m trying to figure out what it is I’m missing. I’ve tried it with vacuum plugged, at base of carb, and connected to vacuum advance. Runs better with the vacuum advance, but still not well.
     
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    • 7mopar

      7moparWell-Known Member

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      I will have to dig the quardrajet and check the vacuum port location out. Have you checked the mechanical advance in the distributor to make sure it functions? Also what is the reluctor gap set at? You may also what to check the reluctor phasing. If off the rotor and coil fire timing will not be correct.
       
    • charm

      charmMember

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      This occurred to me earlier today. I’ll have to do some reading on how to measure all of that, but I’m hoping this is the issue.

      I double checked earlier and at TDC, the rotor points pretty close to the #1 plug, within range of being able to to time it. Thus, I bet I just need to do more to set up the distributor.

      Know of any posts on how to do this?
       
    • 7mopar

      7moparWell-Known Member

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      The factory put arrows on the reluctor that showed distributor rotation. That would be were I would start.
       
    • charm

      charmMember

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      I have it idling well, but when I put a timing light on it, the (I think it's a) magnetic pick up on the dampener is at 6* advanced and the timing mark is nowhere to be seen.

      At TDC, the rotor is pointing to #1 plug wire.

      The pick-up is in between the splines on the reluctor at 0* timing with the rotor point at the #1 plug wire.

      Thoughts with that?

      I won't have time to get to it again until Sunday. Should I try moving the plug wires 4 spots clockwise? Wouldn't that move things 180*?
       
    • 65 sporty

      65 sportyWell-Known Member

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      This may sound dumb, but you have the timing light pickup on the #1 wire right?
      From what I have read you have done everything right, I am puzzled by what is going on. If the marks is in line with 0 when #1 is at TDC and the rotor is pointing to the #1 terminal you should be able to see the mark with the timing light. Timing light pickup on #1 and vacuum advance disconnected the mark should be visible. If it's idling good the timing has to be close
       
    • 7mopar

      7moparWell-Known Member

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      Magnetic pickup on the dampener? Not familiar with that on a 75 truck engine. Timing mark should be nothing but a groove in the dampener. What side of the timing cover are the timing marks on?
       
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      • charm

        charmMember

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        Driver's side.

        I'm FAR from certain it's a magnetic pick-up. I just think I read that somewhere. It's an indentation, about 1/2' in diameter in the harmonic balancer. It is not close to the timing mark on the balancer, although I have not tried rotating it to see how far away it is.

        I did run a quick test earlier, because the idea popped into my head. I started the truck and moved the pick-up from the timing light around to all of the plug wires. Still couldn't find the timing mark. But it seemed like a good idea.
         
      • 7mopar

        7moparWell-Known Member

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        Just for giggles have you checked the casting date on the block? Something makes me think the timing marks on the cover should be on the other side. But I am not sure what year they switched.
         
      • charm

        charmMember

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        I'll look at the casting number AND look up when it switched...hopefully Sunday. Although I imagine if the crank is for a passenger side casting, it won't matter which side the block ends up on. If that's the problem...ugh.
         
      • 7mopar

        7moparWell-Known Member

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        If the timing mark lines up when TDC is found there should be only two reasons for it to not show up with the light. Cam or ignition timing one has to be off. Just because the distributor is orientated with number 1 on the cap would not mean cam timing is correct. That can only be verified by compression at number 1 cylinder when the crank comes up on TDC on number 1 cylinder. The finger over the plug hole or the removal of the right bank valve cover and watch the intake valve close are the only ways to verify that.
         
      • charm

        charmMember

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        Which is where I started, with the valve cover off, before I started all of this making sure that it was at TDC.
         
      • 7mopar

        7moparWell-Known Member

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        It should not disappear just because its running. With the timing at 6* on the dampener were does the rotor point? That would be where I would start setting timing. Connect a test light to the distributor side of the coil with the ignition switch on. Turn the distributor against normal rotation past number 1 and then turn it with it till the light flashes. Then turn the distributor back to just before to light flashes. It should be real close to where the timing mark will be with it running. Number 1 terminal should be connected to number 1 plug and all should be well. You will not even need the cap on doing it this way. Just make sure to mark where number 1 terminal should be on the distributor housing.
         
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        • Polara_500

          Polara_500Well-Known Member

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          Um, a wild shot here, ignore if I'm off base. Are you messing with one that has the tube going down to the balancer and getting some confusion there?
           
        • 7mopar

          7moparWell-Known Member

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          The tube down the balancer takes an adjustable light. You thinking that's the problem. Would have not been used with a standard 75 electronic ignition. The timing mark will never show threw it when running.
           
        • charm

          charmMember

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          I need to buy a test light, but I'll try this tomorrow.

          I was able to get back to the truck today. I pulled the valve cover, again, to check that it is at TDC. The timing mark on the dampener lined up to zero when the intake and exhaust rocker arms were loose (valves closed) and the piston was at its highest point. I understand that to be the definition of TDC.

          I checked to make sure the plug wires were in order and going to the correct cylinder. All looked good there.

          I changed the fuel pump. It's cleaner now, but I'm not sure it needed replacing.

          I started it up and, same thing.

          I can get the truck to idle pretty nicely, but give it any gas, and it'll stall. I guess that's different...before, giving it gas made it backfire, then stall. I have plenty of room to rotate the the distributor clockwise or counter clockwise from there, but a degree or two of rotation in either direction and it won't start. The timing mark still isn't showing up with the timing light.

          I haven't checked the casting marks, but, logically, I don't think that's the issue. Before changing the distributor, I was able to time it, with this timing light, to 6* advance. Just didn't run well.

          I'm really at a loss here. I've gotta be doing something wrong here, I just haven't got a clue what it is!
           
        • 7mopar

          7moparWell-Known Member

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          I still think your new distributor has some problems with the reluctor, pickup timing and possible air gap. I will try to day to get and post a picture of their alignment. Air gap needs to be set between .008 and .010 with a non magnetic feelers gauge. At this point may not be a bad idea to check all lobes. I have seen some vary of a few .001 in air gap.
          Have you checked the ignition coil?
           
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