glowing spark plugs

Small Block Mopar Engine

  1. challenger57

    challenger57 cuda57

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    What causes spark plugs to glow at the base of were the porselin meets the hex? Not all 8 plugs just 1-3-5-7 that I can see?
     
  2. SGBARRACUDA

    SGBARRACUDA ROY FABO Gold Member

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    This is a very serious condition. Your running way to lean. Which could be the result of many things, vaccum leak, jets to small and or carb.
     
  3. SpeedThrills

    SpeedThrills FABO Gold Member FABO Gold Member

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    I've seen headers and exhaust manifolds glow, but not plugs! What's your combo? Recent history? Seems funny that just one side glows. Maybe can't see the "2-4-6-8" side?
     
  4. challenger57

    challenger57 cuda57

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    The motor is an older crate 360, the carb was running lean a few weeks ago. Gotit off ebay, it is a 750 w/ vac secondaries. It had #63 jets with a pluged power valve which did cause it to run lean. as I said a few weeks ago I changed it to #73 jets and a 3.5 power valve to fit my 7 in. of vac. I can not find any vac leaks. I do hear what sounds like an exhaust leak on the driver side. the exhaust leak is what made me look at in in total darkness finding the whiteish glowing plugs.
     
  5. camd64

    camd64 Remember Landy

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    If it is a dual plane manifold then the lean thing would make alot of sense since the carb. could have a restricted passage on that side. pull the idle mix scew out and spray it with some carb. cleaner and push a little compessed air through it and see what happens.
     
  6. SGBARRACUDA

    SGBARRACUDA ROY FABO Gold Member

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    Are you running to much total timing? What temp does the motor run? What do the insulators on the plugs in the cylinders look like? How much comp?
     
  7. toolmanmike

    toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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    Most dual plane manifolds feed cylinders 1,7,4,6 from one side of the carb and 3,5,2,8 out of the other. I'm guessing an open plenum manifold. You should overhaul yhe Holley or put something else on that you know is good.
    I would also put a new set of plugs in. toolmanmike
     
  8. moper

    moper FABO Gold Member FABO Gold Member

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    What color is the glow? Nothing will get white hot on the outside of the engine. But, there could be some chemical on the plug that could ionize and glow white or blue. How old are the wires and plugs, and what kind? What ignition?
     
  9. 3404speed

    3404speed Ancient Decrepit Member

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    HAD A 2.2 turbo exhaust manifold that glowed red...can't remember what I did to fix it...O2 sensor..I know, I know,jumping the thread, but it would have caused a lean mixture...looked neat at night.
     
  10. C130 Chief

    C130 Chief Mechanical Genius

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    How old are the plugs?

    If they are the resistor type, and the resistor has broken down, they may be arcing internally and "lighting up". Consider replacing them.

    Compare the plugs bank-to-bank. If they are visibly different colors, check your mixture distribution (clean the carb, check vacuum leaks, etc...). If they are similar and the insulator is bright white, try a cooler heat range.

    Personally, I am a big fan of running the coldest plug possible. If you are trying to "read" the plug, you need to get the right heat range first, and then tune the mixture. Running too hot a plug is a common mistake.
     
  11. kennmadruga

    kennmadruga 64dart360

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    ive seen this prob before...the seal at were the porselin meets the hex is leaking or cracked...............i would change plugs with colder ones..... good luck..........
     
  12. challenger57

    challenger57 cuda57

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    A lot of good thoughts- first to say it runs strong, lack of power was not concern, just trying to locate exhaust leak made me see plugs with white glow. It is a dual plane eldelbrock performer rpm intake. comp. i am guessing 10-10.5, plugs are .040 above deck bored .040 over with lots of valve relief cuts. Plugs are new, 1 step colder than stock, changed them after rejetting carb. Yes it does have alot of timing, 50 total but it seems to start and run better with it. Now after rejetting carb T will have to take another look about lower it to about 35. I will try cleaning driver side adjustment, but it does function proper, almost stalling when turned in totally. Wires are fairly new Accell factory cuts and crimped not do it yourselfs. Dist. is stock with vac canister. I have a newMSD mech. advance dist. and wire set I haven't tried yet. A to do along with these other things to try. And the temp is always cool, around 170-180 even with 3.91's except on highway which I do not do unless a must. Thanks guys for all Mark
     
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