4MG Rebuild

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Oxbow, Feb 19, 2024.

  1. broke down plumber

    broke down plumber Medium Load Member

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    Dumb question incoming . Could a sleeve not be machined to fit the hole if sleeve was slightly longer than needed , to do away with the shim ?
     
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  3. Oxbow

    Oxbow Road Train Member

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    Now for immediate questions:
    1. Can I steam clean the block with our hot-water pressure washer, or should I try to avoid getting moisture in the block?
    2. Is it critical to have the bevels going into the lower bores pristine so that they don't catch an o-ring? About half of the liners showed some damage to the top o-ring on the liner, but the other two were good.
    3. If the deck measures good and the counterbores do as well, can a guy get by with just cleaning everything up including where the water grommets go, or is that just foolish - take the block in and have it decked?
    4. Automatically plan on new cam bearings?
    That's about it for now. Thank you guys.
     
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  4. Oxbow

    Oxbow Road Train Member

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    As I understand it you can have the the block cut and Cast L sleeves pressed in, then machine the deck. I suspect that cutting counterbores became popular because it can be done in-frame.
     
  5. wore out

    wore out Numbered Classic

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    CHASIN THE DEVIL'S HERD
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    I would steam the piss out of it. If the lower bore itself is good but just the beveled transition itself has a spot on the thrust side I would get some of that high temp compound and just fill in that low area. Sand it down uniform with rest of block. What you want is an even taper so as to not roll a liner o ring going back. Now this is for sorta minimal wear. Though I have gotten by doing it at wore the Flip out too. The top I would put deck rings in it if it’s cut to 60 on one hole. The bad about that is they may come out with a liner if you get it sure enough hot. Which isn’t a earth shattering thing but a pain no less
     
  6. wore out

    wore out Numbered Classic

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    CHASIN THE DEVIL'S HERD
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    IMG_5449.png
    Finished product of last one I had rings built for. You set up on it and cut it, a machine shop builds the inserts. Then you put retaining compound on and press them in. Set back up on it and cut them down to within 1.5 thousandths then get your draw file and straight edge out. It’s a process
     
  7. Oxbow

    Oxbow Road Train Member

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    Thank you! It may have to go Cat as I don't have the equipment or knowledge to do any of that, and I'm not sure if other machine shops in the area do. Are Counter Bore cutting machines able to cut the bigger diameter for the inserts?
     
  8. wore out

    wore out Numbered Classic

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    CHASIN THE DEVIL'S HERD
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    The rings are no thicker than a shim. I have cut existing rings for a shim after they wear. You can see the lines in that block if you really blow it up. Usually anyone that cuts blocks can do it. I can get you the rings built if you need them
     
  9. Oxbow

    Oxbow Road Train Member

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    I see the lines, but thought they were pretty thick (like maybe a half inch). I get what you're saying now. So on that deep one that we have on #1 they would cut for that ring down to where the counterbore depth is or a touch more? Would we have them all cut the same depth? We have a good local machine shop, just not one that handles the whole block from what I have been told.

    So, I could get someone to come and cut those and then we can press them in here is what your thinking? I like that idea. I believe we can do the epoxy job on the lower bores ok. If I have the rings made do I ask for a specific material? They're not stainless by the looks of your picture.
     
  10. Oxbow

    Oxbow Road Train Member

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    I think I'll run into town and visit the machine shop. I called JPaydirt this morning to see where he gets his machine work done and he said that he didn't think they did truck engine blocks, but maybe the can cut the holes and build the rings. I'll update!

    Thanks Russ!
     
  11. wore out

    wore out Numbered Classic

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    CHASIN THE DEVIL'S HERD
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    I usually go about a 1/4 deep on the rings. They will need a counter bore tool for a 3400 series block. The ring will be roughly the same width as a shim, just needs to fit your cut snug. While still fitting the top of the liner. I do agree cut them all the same. I’ve never liked one deeper than another. Nor have I ever seen shims stacked. Course when you’re in that special spot trying to get by you’ll do things outta character or I have. Some of it worked some of it….ended just like ### lol
     
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