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.

6.2 blocks

Discussion in '1982-Present GM Diesel' started by odee, Apr 6, 2003.

  1. odee

    odee Registered Member

    Joined:
    Feb 5, 2002
    Posts:
    15
    Likes Received:
    0
    Location:
    Big Stone Gap Va
    I broke a crank in my 6.2 replace with 98 model 6.5 that engine developed a cracked cylinder wall. Now I have hauled home four 6.2 engines that were black in color,86 or newer? two piece seal blocks. I have found on all of the blocks to have cracks on the outer bolt holes of the main caps. I use the sub for some light towing of my jeep/racecar sometimes. Also want to build a diesel for my dually which does the majority of the towing. Are these block cracks something to worry about or should I continue to try to find a good uncracked block?
     
  2. bigblock454

    bigblock454 Clack Clack Clack Premium Member

    Joined:
    Jun 18, 2002
    Posts:
    546
    Likes Received:
    16
    Location:
    Terre Haute IN
    This is a somewhat common 6.2/6.5 problem, I suggest you find another block. Goto www.thedieselpage.com they have tons of information on the Gm diesels. Some companies also sell main saddles that are designed to prevent this cracking issue.
     
  3. arveetek

    arveetek 1/2 ton status

    Joined:
    Mar 1, 2002
    Posts:
    722
    Likes Received:
    0
    Location:
    Granby, MIssouri, USA
    Only '82 model year 6.2L diesels were painted red. All following years were painted black. Two-piece rear main seal means it was made before '91. That's when the one-piece rear main came out.

    I would continue searching for a block. My suggestion is to find a '92-93 block with a casting number ending in 599. This was a dual-use block, meaning it was used for both 6.2L and 6.5L engines during the transition years. If it was still a 6.2L, bore it out to a 6.5L and then you'll have an excellent base to build on.

    Check this out:

    http://www.thedieselpage.com/reviews/avanteng.htm


    Casey

    ON EDIT: corrected information....'91 was first year for one-piece rear main seals for 6.2L.
     
  4. Diesel Dan

    Diesel Dan 1/2 ton status

    Joined:
    Feb 27, 2002
    Posts:
    798
    Likes Received:
    0
    Location:
    Warren, Ohio
    I pulled a 6.2 with cracks this past winter. One thing I didn't care for was the main bolt holes weren't chamfered. If starting with a good block I would lightly chamfer the holes.
     
  5. odee

    odee Registered Member

    Joined:
    Feb 5, 2002
    Posts:
    15
    Likes Received:
    0
    Location:
    Big Stone Gap Va
    Are the 599 blocks a one piece seal or two piece? Where would a person turn one up at without having to give his life savings or first born up to get it? I've got another 6.2 I'm gonna try to get it is an early on with the red block hopefully I might just wind up with one that's not cracked. What about the cylinder walls? I was talking to a machinist friend last night and he said someone told him that these engines were bad to wear the cylinder walls about 1 inch down in the bore from the top really bad.
     
  6. arveetek

    arveetek 1/2 ton status

    Joined:
    Mar 1, 2002
    Posts:
    722
    Likes Received:
    0
    Location:
    Granby, MIssouri, USA
    The 599 block is a one-piece rear main seal. I looked up the info, and the one-piece block came out in '91. Good luck on finding one at a cheap price. If the seller knows what he has, it won't be cheap. You'll have to find an individual that wants to get rid of one, in order to get it cheap.

    Hadn't heard that about the cylinder walls. I know when I rebuilt my 6.2L, the cylinder walls had little wear, and there was no ridge at the top. I don't know how many miles were on it. I bought it used from a junk yard. There was rust in the cylinders, and I had to hone them to get the pistons out. After a good honing, I reinstalled the original pistons with new rings. I've logged 100,000 miles on my '82 red block motor since then on the original crank, rods, pistons, valves, etc. Only new bearings, rings, gaskets, timing chain, pump, and injectors. I personally feel that the '82 motors were one of the best years, if not the most powerful due to restricted head designs.

    Casey
     
  7. odee

    odee Registered Member

    Joined:
    Feb 5, 2002
    Posts:
    15
    Likes Received:
    0
    Location:
    Big Stone Gap Va
    thanks guys, I've got a line on another 6.2 I can look at within the next week or so. Were any of the red blocks made after 82? What about heads? I've gotten a couple of good sets now. I was thinking about useing the set off of my 6.5 because they have a fresh valve job and least miles on them. Thanks again
     
  8. arveetek

    arveetek 1/2 ton status

    Joined:
    Mar 1, 2002
    Posts:
    722
    Likes Received:
    0
    Location:
    Granby, MIssouri, USA
    Only 82 blocks were red. All rest were painted black.

    Use the 6.5L heads...they flow better and will deliver more power.

    Casey
     

Share This Page