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Whats the diff in 6.2's?

Discussion in '1982-Present GM Diesel' started by BigBad75K5, Apr 12, 2002.

  1. BigBad75K5

    BigBad75K5 1/2 ton status

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    Whats the diff in 6.2\'s?

    My fathers 84 Sub has a 6.2 in it, the crank broke. I located anouther 6.2 cheep out of an 83 pick up, the 84 has an open intake and the 83 has an egr valve in the middle of the intake air inlet.
    Whats the diff between the two engines?
    Which is better?
    Should I just pull the crank from the 83 and stick it into the 84?
    Any info would be nice, thanks.
     
  2. arveetek

    arveetek 1/2 ton status

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    Re: Whats the diff in 6.2\'s?

    Sounds like the '84 is a "J" code motor, and the '83 is a "C" code motor.

    The J and C stand for whatever letter is found in the VIN number. The J motors are heavy duty, which means they are EGR free, have no emission equipment, and are supposed to produce more power.

    The C codes are light duty, which means they have the EGR and emission equipment, but are supposed to deliver better fuel mileage.

    The J codes are usually only found in 3/4 and 1 ton trucks. All 1/2 ton trucks have C code motors.

    The only internal difference in the engines are supposedly that the heads are designed for more power on the J codes. My experience has been that there is little noticable difference between the two.

    I can almost gurantee you that the '84 block is trashed. What usually happens is that the block cracks around the main bearing webs, allowing the crank to flex and then break. Oftentimes, the crank will break off with a section of the block. I have seen a broken crank with one main cap still bolted to a big section of the block, but it was completely torn away from the rest of the block.

    Whatever the case, I imagine the '84 block is no good. So, you might as well use the complete '83 motor. Just go ahead and use the '84 open J code intake on the '83.

    Hope this helps.

    Casey
     
  3. BigBad75K5

    BigBad75K5 1/2 ton status

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    Re: Whats the diff in 6.2\'s?

    I pulled the oil pan off and found the crank broke right at the counter weight between #4 and the rear main. The block looked fine from what I could see but that does'nt mean anything.
    Do you think that I should put a new timing chain in the 83 motor? II've got to put a new timiming cover gasket on it.
     
  4. arveetek

    arveetek 1/2 ton status

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    Re: Whats the diff in 6.2\'s?

    Do you know how many miles are on the '83?

    As far as the '84, just imagine how much stress the main bearing caps had to go through when the crank went. If you wipe down all the main bearing webs real good, especially near the crank failure, watch for a few minutes. If you see oil appearing as if out of nowhere, in small, hair like fashion, then those are definite cracks.

    Casey
     
  5. BigBad75K5

    BigBad75K5 1/2 ton status

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    Re: Whats the diff in 6.2\'s?

    The fella said it had about 250k on it. But he also said the local chevy dealer put two new pistons in it for his father about 3 years ago. He didn't say why or seem to know what all was done. He said he took it out because it had a rough idle and his wife didn't like the diesel motor so he put a gas motor in it.
     

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