Thoughts on welding cast alumium block? Help?
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  1. #1

    Thoughts on welding cast alumium block? Help?

    Hello guys all i need some welding advise/help, I have a engine block that has a damaged main oil gallery basically a chunk is missing.
    The block is cast aluminum and the block itself cost $5k if i were to buy one online so i am wondering if this can be fixed with a piece of cast
    aluminum cut out to match the broken piece out of the block and tig weld it with 4043 filler rod?

    Any advice will help.
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  2. #2
    Join Date
    Oct 2015
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    Re: Thoughts on welding cast alumium block? Help?

    I am not sure why that broke out , it is a thin section that should not see much stress. I see no reason why it could not be tig welded and be perfectly fine. I personally would probably use 5356 but if I remember right there is an advantage to 4043 on cast. I am a little fuzzy on that. There is a 49xx aluminum filler that might be the ticket for this. I do not remember the exact number on it but A quick search on WW of welding cast aluminum will answer the alloy question real fast. I know I would weld it before entertaining replacing it.

    I would not piece in anything, I would just build it up with weld. That is the primary reason I would not like to use 4043. It needs base metal dilution to gain strength where 5356 does not.
    Last edited by thegary; 12-08-2018 at 02:46 PM.

  3. #3
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    Re: Thoughts on welding cast alumium block? Help?

    Not sure about your particular case but I can tell you my experience with welding an aluminum block for a 70 HP Evinrude engine. My son and I found a pretty nice Evinrude engine except for the part where it had a hole in the side of the block caused by a failed connecting rod. We took the engine apart and I took the block to a guy who is a superb TIG welder and asked him about patching it. He suggested I make a patch to fit and then he would weld it in place. I made a patch plate that fit into the trimmed up hole perfectly with suitable chamfers on the block and patch. He welded the patch in place and I took the block and skimmed the head surface and bored all the cylinders oversize just in case there was any warping of the block -- there was little if any warping. We put the engine back together, ran ran it for two years, sold it and so far as I know, it's still running. Given the cost you post about a new block, I'd say it's worth a try to see if you can repair it. But find somebody who really knows what he's doing to make the welds for you.

  4. #4
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    Re: Thoughts on welding cast alumium block? Help?

    Need to figure out why it broke. If it threw a rod there could be other hidden damage in the form of distortion that makes the block unusable.
    Otherwise, sure weld it up. Any oil passages in there?

  5. #5
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    Re: Thoughts on welding cast alumium block? Help?

    I'm "Not There." Can it wait six weeks or so ?

  6. #6
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    Re: Thoughts on welding cast alumium block? Help?

    Quote Originally Posted by thegary View Post
    I personally would probably use 5356 but if I remember right there is an advantage to 4043 on cast.
    Elevated temperature service?

  7. #7
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    Re: Thoughts on welding cast alumium block? Help?

    One thing I will say is you need to determine if it is die cast or sand cast. The pic is a little fuzzy but it looks to have a rough finish so I would say sand cast. If it has a smooth finish like most motorcycle engine blocks it is probably die cast. Some die cast does not weld very good because the add a lot of zinc to the alloy to make it flow better in thin areas.

  8. #8
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    Re: Thoughts on welding cast alumium block? Help?

    My shop primarily repairs castings, iron and aluminum. 4043, 4943, a356 used them all on engine castings and see no great difference, they all work. On a small hole like this i would probably not patch, just fill in with weld. Preheat 350 degrees, weld, post heat 350.
    Peter
    Equipment:
    2 old paws
    2 eyes (that don't look so good)
    1 bad back

  9. #9

    Re: Thoughts on welding cast alumium block? Help?

    Thanks guys a rod actually broke and hit the area. and damaged the oil pan, the oil pan i can replace but this area in the picture is a chunk from the block. This block is from a dodge viper V10 they are 356-T6 aluminum alloy block.

  10. #10
    Join Date
    Mar 2015
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    586

    Re: Thoughts on welding cast alumium block? Help?

    That is a pretty small picture so its hard to tell everything that is going on there. I would seriously consider installing a sleeve in the hole rather than welding.

  11. #11
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    Re: Thoughts on welding cast alumium block? Help?

    Welcome to the forum vacp

  12. #12
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    Re: Thoughts on welding cast alumium block? Help?

    Quote Originally Posted by castweld View Post
    My shop primarily repairs castings, iron and aluminum. 4043, 4943, a356 used them all on engine castings and see no great difference, they all work. On a small hole like this i would probably not patch, just fill in with weld. Preheat 350 degrees, weld, post heat 350.
    Peter
    Good to see you're still around.

    OP, this is the guy to pay attention to as if I remember correctly, block/ head repair is a major part of his business.
    My name's not Jim....

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