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Heat Range (spark plug)

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Hossbaby50, Mar 10, 2004.

  1. Hossbaby50

    Hossbaby50 3/4 ton status

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    How do you determine the best heat range of spark plug for your motor? trial and error or is there a good way to tell?

    I am currently running AC Delco 43 series since the TPI swap. I pulled a plug yesterday and it looked pretty good. Light tan color.

    Can someone give me a recommendation for my setup? Stockish 350, MAF TPI, MSD wires, stock coil, 195* stat. runs at about 200* or so at cruise RPM. I see a mix of DD and highway use. 1200 ft elevation.

    I am thinking about switching back to the plugs I used to run before the TPI. Champion Truck Plugs #4018. any insight on this?

    Harley
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    the best way ive found is, trail and error /forums/images/graemlins/dunno.gif

    if it is a light tan then it is almost perfect, you may wanna try a r44ts.

    i dont like champion plugs and they don't like me. i put some in my truck and they lasted 2 months before 4 fouled /forums/images/graemlins/dunno.gif, put the ac delco 45s back in and ran great
     
  3. 84_Chevy_K10

    84_Chevy_K10 Banned

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    If you have plugs fouling, you either have the wrong heat range or an overly rich fuel mixture.

    Don't blame the brand of plugs if they're fouled, unless they're Bosch trash.

    I'd personally start with whatever is recommended for the TPI engine and adjust if necessary, but you probably won't have to mess with it.

    If they're a good tan now they're probably fine.
     
  4. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    they were the same heat range as the ac delco (acouding to the champion book) /forums/images/graemlins/dunno.gif
     
  5. POWERMAD

    POWERMAD 1/2 ton status

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    I think they are called Champions because if you insist on using them you become a champion at replacing spark plugs.
    Personaly I wouldn't run that plug in anything other than a lawnmower.
     
  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I think they are called Champions because if you insist on using them you become a champion at replacing spark plugs.
    Personaly I wouldn't run that plug in anything other than a lawnmower.

    [/ QUOTE ]

    OEM on Chrysler applications. /forums/images/graemlins/eek.gif

    I personally always run AC plugs in all my Chevys though.
     
  7. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Harley, I have a higher compression motor (83 305 9.2:1) and I usually run a range colder to keep from pinging at cruise in OD. I have regular ones in now, as Autozone was out last week. And sure enough once in awhile I can hear a light ping. With my new 33's I am not running OD much, so its no big deal. Gonna put the cold ones back asap though before it hits 100 degrees here. /forums/images/graemlins/thumb.gif
     
  8. Hossbaby50

    Hossbaby50 3/4 ton status

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    Ya, I might stay were I am for now. I will turn more RPM then you though because of the 4.56's and I would also never hear any pings because the computer would back my timing off now that the TPI is in my truck.

    I think I am just going to throw a set of Champion 4018's back in. I always had good luck with those plugs in this motor before the TPI. Hopefully that luck will continue. If not I will have my buddy (works at checker) warranty them for a set of Champions which are the next heat range down.
     
  9. 84_Chevy_K10

    84_Chevy_K10 Banned

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    You run platinums?
     
  10. Hossbaby50

    Hossbaby50 3/4 ton status

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    Nope, I run standard AC Delco's or I run Champion Truck Plugs. Neither are platinums. I won't run platinums because I have heard you can't pull them out, clean them, gap them, and then put them back in. I like to pull my plugs every now and then and see how everything looks and check my gaps out. Can't do that with plats.

    Harley
     
  11. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Ahh, they're truck plugs thus the high part number. I was simply curious.

    I'm not a platinum fan, either.
     
  12. fortcollinsram

    fortcollinsram 1/2 ton status

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    be careful...go too hot and you will burn a hole in you piston...some dude came to NAPA and got some plugs for a 351 that were a bit hotter than stock..it FOCKED up his motor. Just stick with stock...
    Chris
     
  13. R72K5

    R72K5 Banned

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    remember that X ones are extended plug tip ones and are great for getting spark deeper into the chamber and also good for high mileage engines with worn guides and such that are using some oil.

    light tan is preferable color, when engine is running optimum, the right fuel and timing and good condition and correct plug

    the only thing i get mixed up on is which way heat range is higher, higher or lower number, and what exactly it does,

    theres an ac delco plug chart in a link on this page somewhere plus billions of other good info too, save it somewhere to refer to: http://www.acdelco.com/html/pi_plugs_main.htm
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

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    As said before:

    For AC Delco plugs, R stands for resistor, 4 stands for 14 mm, 5 stands for the heat range (higher is hotter) T stands for tapered seat, and S stands for extended tip.

    Higher heat range plugs retain more heat after the combustion process. Lower heat ranges will disipate more heat, and thus the electrode tip will be, "colder" between combustion events, helping prevent preignition.

    As said above, shying on the colder side is always a wise idea if you're not exactly sure what you want.

    Too cold of plugs don't maintain enough temperature to stay clean, so they foul out.

    Too hot of a plug will still be glowing read the next time the intake valve opens with a fresh charge, and if it is glowing too hot, it might ignite the mixture prematurely, causing "preignition" which as stated above, can cause serious engine damage (holes in the tops of pistons are the commonly reported damage).
     

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