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6.5 take out engines - military re-powers

Discussion in 'GM 6.5 Diesel Engines' started by 3500GMC, Mar 24, 2010.

  1. 3500GMC

    3500GMC Stand Your Ground

    4,940
    42
    Jun 7, 2009
    Nashport, Ohio
    How about listing places to buy these engines.

    Places in each state.
    Things to watch out for when bolting into a 'civilian truck'.
    Ones to avoid.

    If one could find an engine in their own state, it would save freight costs and the total cost of their project.

    Any other pointers would be appreciated.
     
  2. WarWagon

    WarWagon Well it hits on 7 of 8...

    5,849
    257
    Nov 15, 2009
    AZ
    The 6.2 drop in to replace a 6.5 should be listed as an option. 6.2 blocks are stronger and the engines are more common than a sought after 6.5 by $500.00. You need a different oil feed line to the turbo.
     
  3. bk95td

    bk95td 6.5 nut job/addict

    2,548
    3
    Nov 26, 2008
    Military used 24 volt electrics. ip would have to be converted to use with 12 volts. Many have hummvee style oil pan. Would have to swap with truck style pan. 6.2 N/A used different injectors from 6.5 N/A and turbo. Military used v-belts. Have to swap water pump and plate for surp. drive and crank pulley. Accessory brackets to surp drive. If converting to electronic ip the timing cover and timing crank sprocket.
     
  4. 6.2 turbo

    6.2 turbo Active Member

    1,337
    15
    Jan 3, 2010
    pa
    I used to think 6.2 's were stronger until I pulled the pan of one at the junk yard ,it looked like brand new inside, but the block was cracked at the mains so bad that the cracks no longer lined up. The way I see it a 6.5 or 6.2 block is like bending a wire till it brakes,the blocks will flex for certain amount of times until they crack ,I believe it could be related somewhat to mileage. There is some cheap military 6.2' s on ebay ,but as is.
     
  5. I am going to go with a new block......... unless the diesel fairy leaves a P400 under the pillow.
     
  6. bk95td

    bk95td 6.5 nut job/addict

    2,548
    3
    Nov 26, 2008
  7. midniteplowboyy

    midniteplowboyy Recruit

    368
    0
    May 5, 2008
    NE, Texas
    If you run across later model HMMWV engines they could be equipped with the CPS timing cover and reluctor gear(required for the 4L80), also serp/reverse rotation water pumps.

    All Optimizer's should have the CPS setup, water pumps could be either way. I think the serp drive crank pulley is the same as the trucks(just take the spacer out).

    If you want to keep the DB2 pump, just swap the top off an old 12v pump or swap the solenoids.
     
  8. WarWagon

    WarWagon Well it hits on 7 of 8...

    5,849
    257
    Nov 15, 2009
    AZ
    Recall a 6.5 is a bored out 6.2. Advantage 6.2 for thicker cyl walls.
    The pistons are thicker in a 6.2. Advantage 6.2.
    Most 6.2's were non turbo --> less power = less stress. Advantage 6.2.
    6.2's couldn't get out of their own way resulting is full power high RPM running with black smoke. Advantage 6.5 turbo.
    6.2's cost less...

    As they are the same block with diffrent bores thay share a lot of common parts and problems.

    Edit:
    Compression ratio is higher on the 6.2. So a 6.5 setup put on a 6.2 has to run less max boost for the turbo master type users.
     
    Last edited: Mar 28, 2010
  9. 6.2 turbo

    6.2 turbo Active Member

    1,337
    15
    Jan 3, 2010
    pa
    I was thinking of the main webs,are the pistons definetly thicker ? I guess I could continue my search for one that is crack free.
     
  10. 3500GMC

    3500GMC Stand Your Ground

    4,940
    42
    Jun 7, 2009
    Nashport, Ohio
    Upon buying and checking out this 6.2 I now have, I have concluded- there is more MEAT in the block of a 6.2, PERIOD. With the extra bore dia. in the 6.5, flexing/cracking is the norm. When you stop and think why did GM go to 10mm outer main bolts in the 6.5, the pieces of the puzzle start aligning. Pistons in the 6.2 ARE thicker. I think GM thinned out the 6.5 pistons to compensate for the bigger dia. and to maintain 'bob weight' so the engine would not shake itself apart.

    Of course this is comparing OEM to OEM.
     
  11. WarWagon

    WarWagon Well it hits on 7 of 8...

    5,849
    257
    Nov 15, 2009
    AZ
    My 1988 6.2L ate the glow plugs when they came on at 65 MPH. Ate = blown in half. Replaced the defective sensor and the glow plugs. 50K later when I overheated and cracked a head the glow plug parts were still impacted in the piston tops when I removed the head.

    Something about thick pistons…
     
  12. WarWagon

    WarWagon Well it hits on 7 of 8...

    5,849
    257
    Nov 15, 2009
    AZ
    Stripped my 6.2 surplus engine down to the short block. You could eat off the valve covers. Looks like the engine was rebuilt and left as a spare. It was a 12v engine. I do not have to retime a IP. Just turned it up.

    Used 6.5 manifolds on it and changed the head gaskets w/ ARP studs. I have to adjust the TPS I transferred over to the 6.2 IP. Swapped injectors to the short body units.

    The H. balancer was shot on the 6.2.
     

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