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propper spark plug gap

Discussion in 'The Garage' started by big_truxx, May 5, 2005.

  1. big_truxx

    big_truxx 1/2 ton status

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    just a quick question on gap. on HEI ignitions what do you gap them @? haynes says 45 a friend of mine told me 60 and my dad 50... I was thinking 50 would be good average of opinion but what does everyone w/ more knowledge than me think? :D
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Later it's pretty much all .035, though some .045 was thrown in depending on application. .060 was used the first year of HEI IIRC.

    Different engine, but Olds ran up to .080 gap on their plugs with the exact same ignition as Chev, so in our case, you can run just about anything you want.

    I tried .035, .045, .50 and none made any difference compared to the others in how it ran or economy.
     
  3. big_truxx

    big_truxx 1/2 ton status

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    :thinking: may go w/ 50 :dunno: had 40 or 45 think 50 won't hurt it. although i think i need to learn how to tune my holley :haha: thik it may be putting too much fuel through to the cylinders :D
     
  4. sled_dog

    sled_dog 1 ton status

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    I would go with .35, thats what I always gap to. If you had an MSD ignition I'd say go 50 but I don't think you do.
     
  5. big_truxx

    big_truxx 1/2 ton status

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    no it does not need msd :haha: :D its just my 82 crew dually 350/400 w/ 3.73's :waytogo: just needs to run well and all that good stuff. just has a basic HEI on it nothing special. :thinking: maybe I should go w/ 35... the plugs seemed a touch damp when I pulled them... maybe a little closer would spark better... also should learn to tune carb :D
     
  6. sled_dog

    sled_dog 1 ton status

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    both good ideas I'd say
     
  7. big_truxx

    big_truxx 1/2 ton status

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    and ditch the headers ;)
     
  8. sled_dog

    sled_dog 1 ton status

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    thats your thing.
     
  9. Hossbaby50

    Hossbaby50 3/4 ton status

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    I run .045 with my TPI. I ran .057 when I had MSD and a carb.

    Harley
     
  10. diesel4me

    diesel4me 1 ton status Premium Member

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    Wide gaps not good..

    I used a set of R45tsx "extended gap" plugs I got given to me free during a garage clean out--I gapped them at .080 like they said to (they actually belonged in a 231 V6,or Olds V8's!)--I noticed the idle was a bit smoother,and my mileage improved slightly--but I noticed more that I now had a "hiccup" upon acceleration,and if I floored it quick sometimes it would spit back trhu the carb...and the first 15 degree day we had...I noticed it would not start!! PERIOD!..the plugs were soaked like I had NO spark!--

    After removing them and putting the normal R45ts plugs back in,it started fine all winter,and my hiccups and backfires dissapeared too..my brother told me GM had troubles the first year HEI came out,they got a little carried away with how far a gap they thought HEI could jump,many cars had cold weather starting troubles,and they had the dealers install the R45TS plugs gapped at .045 on V8's and V6's,,.035 on straight sixes..that cured that problem... :crazy:
     

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