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Thread: Poor Performance When Hot

  1. #91
    Registered Member
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    Nov 2015

    Member #:2764
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    649
    Thanks. Before the distributor started getting worse and worse, I was running AC 42's and they were burning nice. Then with the AF gauge addition and setting the carb richer, I changed to hotter 43's. Then after a while they started looking too cold. I didn't know what was going on with the darn distributor and went to 44xt's and they still looked bad. The porcelain was medium brown and I think they had soot on the base of the threads. Now those same plugs cleaned themselves with the only change being the distributor. I can probably go a notch or two colder now. If I do, then is it a good chance I can advance the timing a bit? Maybe best I wait till the timer at the track is working.

    Most of the plugs are hard to read because some time ago I thought I had a knock and was using off the shelf octane booster which turns the plugs orange, now that orange is a sort of bright yellow. Turns out the noise was not pre igniton, hell I can't even recall what it was now? I had changed 1 and 2 so I could read them without the orange crap some time ago. I'm just so fricken happy it runs like it should again. I've heard MSD RTR's called Ready to Quit, and now I have a little round circuit board that agrees. I think I'll hang that little bastard on the wall with the oil pan baffle that the spot welds broke loose.
    Tony

    1955 Bel Air Sport Coupe

  2. #92
    Junior Member
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    Jun 2018

    Member #:3817
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    27
    Glad you found it. Sometimes the simpler problems are the hardest to find. Frustrating at best!

  3. #93
    Registered Member chasracer's Avatar
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    Mar 2018

    Member #:3718
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    Sounds good on adding some additional timing with colder plugs. You might want to see how cold you can go. Back in the day (as they say) a "normal" small block Chevy would run Champion J-12Y plugs but I found that I was able to get down to a J-10Ys without any issues and turn up the timing a bit which helped get that sled moving. Of course there's a world of difference in the fuel today.

    I once chased a mid-speed misfire on a Buick engine for months. I can't remember all the crap I changed trying to find it and it ended up being a cracked ground lead inside the HEI unit. Soldered it back together and it ran great again - until my newly licensed teenage son decided to grenade the engine one day on the way to school....

  4. #94
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    Nov 2015

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    Right now my timing is advanced 18°. Cranks easy and no ping/knock. Is there any reason to bump it up a little till it gets hard to start (kicks back) then back off a little?
    Tony

    1955 Bel Air Sport Coupe

  5. #95
    Junior Member
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    Jun 2018

    Member #:3817
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    Quote Originally Posted by 55 Tony View Post
    Right now my timing is advanced 18°. Cranks easy and no ping/knock. Is there any reason to bump it up a little till it gets hard to start (kicks back) then back off a little?
    What worked for me was to pick a warm day and bump the timing almost til the motor starts to buck when cranked. Take it out and drive for a while to get full heat, then pick a long hill and push it some til it starts to ping. Pull over and back it off a tiny bit. Kept doing that a few times til the ping was gone. Of course some things like outside temp and different brand fuel would change things a little, but overall would be a good system for a street car. After everything was good I'd only then check the timing numbers and write it down somewhere (usually lost though). I'd do that for when cam or intake change time came. That number would get things back to close.

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