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HEI Gripes

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by BluThndr71JMMY, Feb 1, 2003.

  1. BluThndr71JMMY

    BluThndr71JMMY 1/2 ton status

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    Got an HEI on my ('98) crate motor 350 in my '71 Jimmy. On a warm day the ignition will crap-out on me after the engine gets hot. I replaced the module after someone told me that was my problem. After about 400 miles it's doing the same thing again. Is it the coil too? After about a 15 minute to 1 hour wait, the engine will start up and run just fine.I know it's not vapor lock. <font color="orange"> </font color>
     
  2. 70~K5

    70~K5 1/2 ton status

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    did you put the stuff under the module when you installed the new one?
     
  3. chevyracing

    chevyracing 1/2 ton status

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    When you took out the points dist and put in the HEI did you run a 12 volt wire to it? The factory wire that is used for the points type is not a full 12 volts and that could be causing the module to pull too hard and the result is it overheating. Another issue that can cause that as well is loose connections. If a connection is loose it will also cause a heat problem..

    John
     
  4. BluThndr71JMMY

    BluThndr71JMMY 1/2 ton status

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    '70-K/5: --Yes, I used the White Stuff. Probably white lithium grease. Both on the new unit and the old. Also used the included silicone dielectric (clear) grease under the rubber grommet on the new coil, along with a new cap and rotor today. [The old coil was installed 4/2000, old rotor looked oxidized and old cap was getting brittle] It started up good. I'll test run it tomorrow.Chevyracing: I don't remember getting a separate pure 12 VDC wire for the HEI distributor, I think I'm still spliced into the old wire that ran to the ballast resistor. Something to check out. If I do need a new lead, what gauge wire should it be and what source should I tap into? Excess resistance might just be why I kept burning up plug wires a couple of years ago... I thought it was the headers!Thanks Guys.
     
  5. chevyracing

    chevyracing 1/2 ton status

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    I put a HEI in my 72 and used good quality (Carol Cable brand) 14 gauge wire (multi strand) and ran it to my ignition switch. Haven't had a single problem since. I have an inline 20 amp fuse, that may be a little heavy though.

    John
     
  6. Steve_Chin

    Steve_Chin 1/2 ton status

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    The factory pink wire *is* a resistance wire. You must bypass it and run a moderate gauge copper wire to the HEI, or it will not run properly. I used a 37 strand 12AWG wire on my Blazer, along with factory terminal housings so that the strain reliefs work properly.
     
  7. arq

    arq 1/2 ton status

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    everthing is pretty much covered up above, another thing to check is ground wires. make sure they go everywere, chassis to batt, engine to batt to chassis to fire wall, etc. they put them there for a reson.

    ARQ.
     
  8. 70jimmy

    70jimmy 3/4 ton status Premium Member GMOTM Winner

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    Ballast resistor If that is the ceramic looking block thing on the firewall you need to get rid of that. I followed the wire to where it starts and ran a new one. Took the ballast resistor off the firewall and threw it away. I understood that with the old points system once the vehicle got running the voltage dropped because of that since the point system didn't need it. HEI needs full voltage all the time.

    HEI rocks once you get it set up. Except for when you blow the module then you are dead in the water. So keep an extra and some dielectric grease handy.
     
  9. BluThndr71JMMY

    BluThndr71JMMY 1/2 ton status

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    Chevyracing: Do I need a full 20@ fuze?ARQ: I put a new [M &amp; J] Firewall - Headlamp wire harness on last year, cured my runaway regulator gripes -- so I've been the whole grounding route already.Block is connected to frame w/ 1" braid.Dr. Chin: Where do I get Pink 12 ga. and factory terminals?'70Jimmy: I deleted the ballast resistor along with the old point distr, but I have it on hand in case I want to get one of my storage rigs running again. Chevy distributors work on any Chevy V-8, big or small block.On the whole, I think it's cheaper to get a new performance HEI from Jeg's or Summit, complete, than to get one from a junkyard and build up with new components.
     
  10. kiley

    kiley Registered Member

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    I just pulled my points distributor. When I tried to put the HEI distributor in it would not go all the way back in with the rotor facing the same direction. It's about 90 degrees off from what it was. What do I do? I thought that all chevy hei distributors worked with all engine. Please help!
     
  11. 70~K5

    70~K5 1/2 ton status

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    It doesn't matter where the rotor is pointing as long as it's pointing at the #1 plug wire and the firing order is right. You can switch the wires around on the cap for this.
     
  12. kiley

    kiley Registered Member

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    Do I need to find tdc on #1 and then lay out the wires in the appropriate firing order?
     
  13. 70~K5

    70~K5 1/2 ton status

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    Pull #1 plug and hold a finger over the hole as you turn the motor over to find the compression stroke and then turn the motor back to TDC to start out with. As long as you're not using one of those CRAB flat caps you should be fine. /forums/images/graemlins/thumb.gif
     
  14. BluThndr71JMMY

    BluThndr71JMMY 1/2 ton status

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    OK, I ran a new red 12 ga 20-strand copper wire from the fuze block to the "BAT" terminal on the Distr. Seems to run good. Also noticed my headlights don't flare and dip with RPMs anymore.Chevyracing, you called it!Funny how I got by so long on the yellow wire. It did check out at 12.25 vdc while cold. I traced the circuit out in the 1971 CT-CSM (p 12-26): It starts with the 12pnk3B wire at the Ign Sw which runs to 12pnk3A at the Bulkhead Connector, Terminal 3A, while splice 3 goes to "IGN UNFUSED." On the engine side of the bulkhead connector, Terminal 3 feeds out 20wht/or/ppl Cr.Tr.3 (?) [this is the resistance wire--single strand] to splice 3-7 forking into 20yel7 to the starter solenoid and 20yel7A to the (stock) coil.Thanks guys.As far as lining up the timing: Bump the engine over to line up the mark on the harmonic balancer with the TDC mark on the timing index. If you don't trust it, pull plug #1 and put your finger in the hole -- when compression pops it out, you're there. Once you're at TDC the rotor should point to the first cylinder. Make sure the distributor shaft is seated in the slot on the oil pump drive and the distributor seats all the way down.Good luck.
     
  15. kiley

    kiley Registered Member

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    There are two spots, 180 degrees apart from each other, where the distributor will seat all the way down. Does it matter which "side" I use?
     
  16. 70~K5

    70~K5 1/2 ton status

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    You can take a long screwdriver and stick it down the hole the distributor came out of and turn the oil pump drive to line up in a different spot too. /forums/images/graemlins/thumb.gif
     
  17. Steve_Chin

    Steve_Chin 1/2 ton status

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    I couldn't find pink, so I used red wire like you did. The factory housings I got off of cars in the wrecking yards (just bring wire cutters, hack 'em off, then separate the housing from the terminal in the comfort of your own La-Z-Boy). I got the terminals from Chevy Duty.
     
  18. BluThndr71JMMY

    BluThndr71JMMY 1/2 ton status

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    I think Francis Wire Works sells the GM-type terminal connectors. Not having the patience for a mail order wait, I just used 3M crimp-on terminals with a heat shrink collar, and called it good. /forums/images/graemlins/k5.gif
     
  19. Steve_Chin

    Steve_Chin 1/2 ton status

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    Ahhh... But not using the factory terminal housings leaves you with a single point of failure where the terminals connnect. The factory housings have latches to prevent the terminals from vibrating loose. If you bash your Blazer much, you could end up with your ignition mysteriously dying on you due to the terminals vibrating apart...
     

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