Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Going to HEI....one ?

Discussion in 'The Garage' started by steedalx, Oct 19, 2004.

  1. steedalx

    steedalx 1/2 ton status

    Joined:
    Dec 19, 2003
    Posts:
    142
    Likes Received:
    0
    Location:
    Chattanooga, TN
  2. ben427

    ben427 1/2 ton status

    Joined:
    Mar 10, 2002
    Posts:
    1,123
    Likes Received:
    0
    Location:
    Waverley, Nova Scotia
    Yep and you also need to run a larger ignition wire to the distributor to replace the smallish stock one.
     
  3. steedalx

    steedalx 1/2 ton status

    Joined:
    Dec 19, 2003
    Posts:
    142
    Likes Received:
    0
    Location:
    Chattanooga, TN
    OK I got it ordered, should be in by the weekend. I'm just looking through my Haynes manual and trying to determine which wiring diagram to use. Can someone go over which wires go where on the HEI unit.
     
  4. 3 on the tree

    3 on the tree 1/2 ton status

    Joined:
    Oct 16, 2004
    Posts:
    3,970
    Likes Received:
    0
    Location:
    gunnison colorado
    If I remember correctly, from my 70 Burb, All you need to do is put a new end on the hot wire that went to the coil and plug it into the IGN port on the new HEI. Its been about 20 years since I did this swap, but I remember that it was dead nuts simple. If I'm wrong, I'm sure that someone else will jump in and expose my poor memory.
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,546
    Likes Received:
    937
    Location:
    Massachussetts
    You need to run a new 10 or 12 gauge wire from the fuse block(hot only when key is in the "on"position)-the original wire to the points style coil is a resistance wire,wont allow the full 12 volts and amperage the HEI needs to work properly--sure it will run,but not at full spark potential.At my friends shop nearly every(older) GM truck he has worked on the owner had swapped in an HEI distributor had used the original coil wire--that turned out to be the reason the truck was brought in for a "tune up"more often than not--the trucks would not run well while pulling a load,or taking off from a dead stop,but ran ok under lighter loads--classic symptoms of weak spark.Low voltage to the HEI module can shorten its life quite a bit also. /forums/images/graemlins/crazy.gif
     
  6. ntsqd

    ntsqd 1/2 ton status

    Joined:
    Nov 28, 2002
    Posts:
    3,381
    Likes Received:
    0
    Location:
    So. CA
    You can also use a relay. Trigger it with a IGN only hot wire (like the original points coil wire), and pull the high amp power from the battery.
    I have some concerns about pulling the kind of current an HEI requires thru a circut not designed for it.

    Another way to go if you're considering using a MSD or similar box is to go with a small body HEI from Dave's Small body HEI's. Don't know the URL exactly, but a search should turn him up. Basically what he does is put the pick-up coil and relutor from an HEI in a points dist body. I can also do this work, but right now I'm back-up too far to take on more work.
     
  7. steedalx

    steedalx 1/2 ton status

    Joined:
    Dec 19, 2003
    Posts:
    142
    Likes Received:
    0
    Location:
    Chattanooga, TN
    [ QUOTE ]
    You need to run a new 10 or 12 gauge wire from the fuse block(hot only when key is in the "on"position)-the original wire to the points style coil is a resistance wire,wont allow the full 12 volts and amperage the HEI needs to work properly--sure it will run,but not at full spark potential.At my friends shop nearly every(older) GM truck he has worked on the owner had swapped in an HEI distributor had used the original coil wire--that turned out to be the reason the truck was brought in for a "tune up"more often than not--the trucks would not run well while pulling a load,or taking off from a dead stop,but ran ok under lighter loads--classic symptoms of weak spark.Low voltage to the HEI module can shorten its life quite a bit also. /forums/images/graemlins/crazy.gif

    [/ QUOTE ]

    Thanks for the help. Now this new wire that I run to the Coil, do I need to do it like the points system and splice a wire from it to the starter? Thanks
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,546
    Likes Received:
    937
    Location:
    Massachussetts
    You only need the one (new)wire--the old points system had a wire from the solenoid to by pass the resistance wire and give the coil full 12 volts while cranking only,to increase the intensity of the spark--HEI needs 12 volts direct,with no resistance,use a heavy wire like 10 or 12 gauge,it draws quite a bit of juice. /forums/images/graemlins/crazy.gif
     
  9. steedalx

    steedalx 1/2 ton status

    Joined:
    Dec 19, 2003
    Posts:
    142
    Likes Received:
    0
    Location:
    Chattanooga, TN
    Makes perfect sense....thanks
     

Share This Page