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Spark Plug Heat Range Question...

Discussion in 'The Garage' started by 1-ton, Feb 13, 2005.

  1. 1-ton

    1-ton 1/2 ton status

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    My 1985 K30 with a Big Block 454 is specified for AC-Delco R44T spark plugs, but I would like to go with one range hotter, in order to make sure I pass an emissions tail pipe test. Would AC-Delco R43T spark plugs be the next step up in heat range?
     
    Last edited: Feb 13, 2005
  2. 1-ton

    1-ton 1/2 ton status

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    Kool! Thanks :).
     
  3. diesel4me

    diesel4me 1 ton status Premium Member

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    i dont think so---!

    An R 45T would be one range hotter--the R 43T is one range COLDER than a R 44T plug---You probably wont notice much difference,its not that great of a jump up --if you are trying to avoid plug fouling from high oil consumption,or a rich mixture you could use non-foulers with the original heat range plugs(dont use non foulers AND hotter plugs== melted pistons!:frown1: )--I have also used R 45TS ac plugs in the 454's I had that smoked a little--the"TS" series are "extended reach" plugs,they stick out further into the combustion chamber than the "T" suffix plugs do--helps them stay cleaner,and not foul so fast..If you have a high lift cam,different pistons or heads than stock,or a combination of different parts bolted together,make sure the "TS" plugs dont hit the valves or pistons before starting it,if you decide to try them-(crank it slowly by hand with a wrench and make sure you dont feel any contact)-they will work on all stock big blocks with tapered seat 5/8 hex "peanut plugs",but a modified one might not have adequate clearences...:crazy: .
     
  4. ssls6

    ssls6 Registered Member

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    Sorry for the misinformation, my brain slipped a tooth. :blush:
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

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    No biggie!

    Thats ok--My brain has a few chipped teeth on its cogs too!--its not easy to remember all this crap you have to know to be a Mek-n-ik!...:D
     
  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Just so you know, a hotter plug doesn't mean you get a hotter spark, it means that it stays hotter through the combustion process to hopefully stay cleaner.

    I personally never put hotter plugs in engines. I'll put colder plugs in engines that have detonation issues but I never go hotter. R45TS in the trail rig, CR43TS in the old tow rig, R44TS in the old 305s.
     
  7. 1-ton

    1-ton 1/2 ton status

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    Thanks for the info. That is good information Diesel4me. The engine is a completly stock 454 (with roughly 120,000 miles on it), so the plug length will not be a problem. The problem with the engine is that it has one cylinder, which has a valve giude that is getting some (but not too much) oil through it. I just bought this truck, and I need to have it smogged.

    I rebuilt the Quadrajet Carburator on it, and got that adjusted a little on the lean side. Next, I am going to get that set of R45TS plugs, put a new air filter on it, check the timing, make sure the engine is good and hot, and that should do it.
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    yup--tune er up and go for it!

    It might not hurt to add a few bottles of isopropanol dry-gas to the tank just before you go for the sticker,it will reduce the hydrocarbons and CO ,it works best if you have a 1/4 tank or less of gas--getting the motor hot is very important--
    I flunked the emission test many times because after I got the motor good and hot after a few miles on the highway and "beat" it a little to get it good and hot--only to be sidelined in the parking lot of the inspection station,waiting for the guy in front of me to get his car inspected!--even idling the motor doesnt keep it hot enough,might even make it LESS likely to pass!--now I just go for another ride and come back later,and hope I can sneak right in the inspection bay before it cools down....this is why I now own a 74,79,81 gm trucks,and a 82 diesel--NO emission tests if they are 84 and older here!:grin:

    I have used R44T,R45T,R45TS and R46TS plugs in all my GM motors,250 six,305,350,454--and didnt really notice any real difference in plug life or engine performance--the hotter ones would not foul quite as quickly,but still would after awhile--I also tried the "extra gap" .080 thousandths gap plugs once,(R45TS8) but they were too wide a gap to get good starts in the cold weather with them--they did make a slight difference in power,and a smoother idle though,but sometimes I'd get a "hiccup" when accelerating with them,it went away when I put the "regular" R45TS plugs with a .045 gap back in...:crazy:
     
  9. AkMudr

    AkMudr 1/2 ton status

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    Not to hijack, but what would be the best plug for a stock 350 with 123k and leaky valve seals? IIRC ive got the R44TS's right now.
     
  10. diesel4me

    diesel4me 1 ton status Premium Member

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    you can use hotter plugs,BUT---

    You could use R45TS or R46TS plugs,they are one to two ranges hotter--but be aware the hotter plugs MAY lead to pinging or pre-ignition if you tow or drive at high speeds for long distances--listen to the engine while your driving,if it sounds like timing too far advanced,you might want to use the stock # plugs--but I havent had any issues with pinging,and my trucks dont even have the EGR valve hooked up..
    .I've used "non-foulers" on badly worn motors that guzzled oil,but they mask the spark,and raise the heat range way up,so its not a good idea to use them with hotter plugs,things get hot enough to melt sometimes--they also reduce the power of that cylinder,they say not to use them in more than half of the total number of cylinders
    I dont like them,they are a "crutch" to keep a junk motor running a few more miles,fixing it right is always the best way...valve stem seals dont usually foul plugs that quickly unless they are real bad,or the valve guides are shot--if one plug fouls,you can swap it into another cylinder and that will usually burn the oil off and clean it some--or just pop in a new one for 1.59!:crazy:
     
  11. AkMudr

    AkMudr 1/2 ton status

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    That all makes sense. My motor still ****s n gits, but leaky valve seals are causing a lil buildup on the plugs.
     

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