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6.2L donor vehicle

Discussion in '1982-Present GM Diesel' started by grumpy, Jun 3, 2001.

  1. grumpy

    grumpy 1/2 ton status

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    Hey All,
    I have a donor truck I am getting a 6.2L motor out of. Any tips on what else I should remove? BTW, the engine is going into my 74 K-5
    David
     
  2. NewK5Guy

    NewK5Guy 1/2 ton status

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    The 6.2 equipped trucks(to the best of my knowledge) all used the Bendix Hydroboost system for the brakes. The diesel doesn't produce it's own vacuum, so assist for the brakes is provided by the power steering pump. YOu'll need the ps pump, hydroboost lines, and hydroboost master cylinder(yes, it's different). The 6.2 has it's own little mechanical fuel pump and as long as it's working, you should be ok. What year is the donor truck? If it's pre 83, you'll need both the primary and secondary fuel filters. They are spin on affairs. One is mounted on the fire wall on the passenger's side, the other is under the truck(I think) on the passenger's side. If the truck is post 84, there is only one filter. A silver box mounted on the firewall on the passenger's side.
    You'll also need the complete wiring harness as well as the "Glow Plugs/Water In Fuel" dash indicator light. I suppose you could fashion your own as long as you know exactly what circuit works them. You'll need the glow plug relay(usually mounted on the driver's fender with a "High Voltage" warning sticker nearby). You won't necessarily NEED the dual battery setup, but if the donor is so equipped, then it's most likely a 24 volt starting system and you will have to. I don't know that all 6.2's had this setup, but I've seen that most of them do.
    You might as well take the fuel tank and lines as well. You'd have to do a very thorough flushing job to reuse gas lines and tank. Plus, the diesel tank has a special water rejecting pickup that you'll need so it'd be easier to just take the whole thing.

    <P ID="edit"><FONT SIZE=-1>Edited by NewK5Guy on 06/09/01 09:59 AM (server time).</FONT></P>
     
  3. DieselDan

    DieselDan 1/2 ton status

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    I don't mean to "sharp shoot" but....

    All civilian GM diesels are 12 Volt, the batteries are wired in parallel. Only the Mil-Spec CUCV version had 24 Volts (wired in series), and it was actually a 24V/12V system with dual altenators. Dual batteries are a necessity with glow plug cycles and cranking over ALOT of compression.

    Oh ya, Gm improved the glow plug controller and move it to the manifold on later models. (CUCVs never used the civilian style controller but used a seperate circuit board mounted under the dash with a firewall mounted solenoid.

    Real trucks don't have spark plugs!
     
  4. NewK5Guy

    NewK5Guy 1/2 ton status

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    Well I did say "to the best of my knowledge". Better you correct me than a certain someone else. I'm still learning about diesels as all my knowledge is in gas motor workings.
     
  5. grumpy

    grumpy 1/2 ton status

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    My donor is mil spec, are there any pros or cons compared to the civillian diesels? Not sure on the year 84 or 85 I believe.
    Thanks,
    David
     
  6. NewK5Guy

    NewK5Guy 1/2 ton status

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    Someone WILL have to correct me on this, but I think the MIL spec 6.2's were the heavy duty code models(J code). I'm not sure what made them heavy duty though.
     
  7. DieselDan

    DieselDan 1/2 ton status

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    I "believe" the only difference between the light and the heavy duty, was that the light duties had an EGR manifold. (Definately ditch that EGR on a 6.2) But I could be wrong....

    If the donor was Mil Spec (CUCV?) the starter was 24V, you'll have find a 12V or maybe a starter shop can rewind it. Also ditch the glowplugs (probably crap anyway) and get the AC 9G or 60G. The CUCV controller is up under the dash, above the brake pedal, in a little black box, cigarette pack size. It works on 12V (nice long cycles) it controlled 24v for the plugs. Not sure how much of your donor is left, or if you need more advice...



    Real trucks don't have spark plugs!
     
  8. grumpy

    grumpy 1/2 ton status

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    I pretty much have anything I need from the vehicle. It's a CUCV 11/4 ton PU. Do I need the glow plug controller or can I rig them to operate on a manual switch? Was everything on the military trucks 24 volt? Are civilian truck 24 or 12 volts?
     
  9. DieselDan

    DieselDan 1/2 ton status

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    Well, a glow plug controller is nice. A controller will cycle a few times after the engine has started to smooth out the idle, there is also much less chance of blowing the plugs, and others can drive without special training. On CUCV's it's a dual voltage system: starter, blackout lights, aux power for tactical radios and glowplugs* take 24V. Everything else is 12V. The glowplug system was the achilles heel of the CUCV. 24V Volts was routed from the bus bar thru ballist resistors (mounted behind the air cleaner) to the relay on to the plugs. The kicker is the glow plugs actually take 12V courtesy the resistors; BUT if one glowplug fails the remaining will now receive more (13.5v), then another craps out (15v), oops two more die (18v), crap it won't start! It was easy for a savy mechanic to check the health of the plugs by watching the voltage drop, at the relay, during cycling. 24 Volts - relay off, 12 Volts relay on plugs good (more voltage would indicate one or more dead plug).

    The actual circuit board is 12Volt. I'ld keep it, shitcan the resistors, wire the batteries parallel, and invest in the best plugs to-date.

    Real trucks don't have spark plugs!
     
  10. grumpy

    grumpy 1/2 ton status

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    Thank you to all the smoke belchers out there, I appreciate the good info.
    David
     

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