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Thread: Plug Weld CyL Head

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  1. #1
    Luke Skywalker
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    Plug Weld CyL Head

    100_1744.jpg Is this what is meant by having a cracked head plug welded? How reliable is this method? (the orange gunk on the valve heads is grease not rust and wipes right off.)

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    Great Pumpkin TR3driver's Avatar
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    Re: Plug Weld CyL Head

    I could be mistaken, but I believe those are "stitches".
    http://www.hotrod.com/articles/mopp-...-crack-repair/

    That's a very common place for TR2-4 heads to crack. But since there is only water jacket on both sides of the crack, it doesn't seem to hurt anything and the conventional wisdom is to just let it be.
    Randall
    56 TR3 TS13571L once and future daily driver
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    Yoda glemon's Avatar
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    Re: Plug Weld CyL Head

    I have no doubt Randall is right but since you brought up the subject, I don't think it is considered ideal but is often done to parts that are hard to find replacements for. I had it done on my Healey 100 head, which have been described as having two stages in their lives, cracked, or about to crack. This was a few years back when machine shops were a little more common. I assume there is a bit of skill or art involved, because my guy and a couple other gearheads said there was only one guy that could do it, and he was a bit of a magician.

    He did do it for me, I asked if it would hold, he said he wouldn't do it if it wasn't going to be as good as new, I only kept the car a couple years after but nothing blew up.

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    Luke Skywalker
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    Re: Plug Weld CyL Head

    Thanks for the input guys.

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    Obi Wan Sarastro's Avatar
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    Re: Plug Weld CyL Head

    I just brought my TR4A head to a LBC specialist to have it reworked, and the first thing he noticed was a crack in the same place. He said that I probably could just leave it alone, but planned to fix it using the stitching technique. He said welding was an option, but welding cast iron is often disappointing; I don't doubt it.

    As it happened, magnafluxing showed quite a few more cracks, so that head will now see service only as one humongous paperweight. But I have another one that could be OK; we'll see.

    There are a number of videos about the repair of cracks in blocks and heads on YouTube. The process is pretty interesting.
    Steve Maas
    1966 Triumph TR4A, undergoing restoration: http://www.nonlintec.com/tr4a
    1952 MG TD, restoration completed 2014, sold 2016: http://www.nonlintec.com/mgtd
    1960 Austin-Healey "Bugeye" Sprite, sold 2010: http://www.nonlintec.com/sprite
    1967 Porsche 912: http://www.nonlintec.com/porsche

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    Senior Member mt10flyer's Avatar
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    Re: Plug Weld CyL Head

    I always called it a "pin repair" but stitching sounds good too. Here is a pic of the repair done on the head of my Series Land Rover. It has held up nicely, but I think it may be a function of the shop doing the work. My shop does a lot of high performance work and are known to be good.
    head after2.jpg
    My hovercraft is full of eels.
    1959 TR3 SN42940

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    Darth Vader
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    Re: Plug Weld CyL Head

    leave it

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    Jedi Knight
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    Re: Plug Weld CyL Head

    If leaving it does not seem the best option, here is a good discussion, IMO, of repair methods:
    http://www.enginebuildermag.com/2015/04/engine-block-and-head-repair/

    1960 TR3A TS73117 (under restoration year 6, owned since 1964)
    1959 TR3A TS58023 (in case I never finish the one above)
    1969 Triumph Herald 13/60 (a whim)
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    Jedi Warrior BlueMax's Avatar
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    Re: Plug Weld CyL Head

    A more sophisticated way to repair a crack head or block is, flame iron spray welding.

    https://www.youtube.com/watch?v=NXqVO6hFEUI

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    Yoda Geo Hahn's Avatar
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    Re: Plug Weld CyL Head

    Stitching on my TR4:



    I have reason to suspect this may have been done at the factory.

  11. #11
    Jedi Knight AltaKnight's Avatar
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    Re: Plug Weld CyL Head

    Lock & Stitch is it's name. Reliable when done properly, yours looks good from what I can see.
    Cheers, Graham
    '73 TR6; Olive Oyl;
    '07 Mercedes SL550 Roadster

    If I had it to do all over again .... I probably would .... if I could remember how!

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