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Technical Can a cracked piston be welded?

Discussion in 'The Hokey Ass Message Board' started by Dirty30Dodge, Sep 2, 2018.

  1. Dirty30Dodge
    Joined: Jan 10, 2009
    Posts: 538

    Dirty30Dodge
    Member
    1. Upholstery

    These are old Chevy 302 Pistons pre DZ. I pulled them from a small journal 327 that had a steel 283 crank. It was in my 57 Chevy that I found in garage parked in there since the late 70's. I wanted to sell the Pistons then noticed this crack. Can it be welded? I am not certain if they are forged. They have a weighted steel plate one each side were the pin goes through? Which is behind the crack in the 1st picture.

    [​IMG][​IMG][​IMG]


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    kidcampbell71 likes this.
  2. goldmountain
    Joined: Jun 12, 2016
    Posts: 2,719

    goldmountain

    It wouldn't be worth trying. Would you feel comfortable with an engine that could possibly grenade on you?
     
    dana barlow likes this.
  3. i'm sure they are cast
     
    Max Gearhead and squirrel like this.
  4. Nobody want to buy a welded piston.
     
    GuyW likes this.

  5. Yes, I have heard of people welding pistons.
    Generally, holes in domes.
    Distorting ring lands is a potential problem.
     
  6. BadgeZ28
    Joined: Oct 28, 2009
    Posts: 1,095

    BadgeZ28
    Member
    from Oregon

    Don't chance it. You are lucky you have a motor that has literally dozens of piston manufactures offering a white array of options. I image stock class racing requires pistons similar to what was stock.
     
  7. KenC
    Joined: Sep 14, 2006
    Posts: 544

    KenC
    Member

    Cast piston. Most common small block crack ever. I've seen all 8 cracked on early 265/283s 'back when'. The steel strut inside is for expansion control and is one of the many reasons welding is a bad idea.
     
    Hnstray and Unkl Ian like this.
  8. sbtslick
    Joined: Jun 19, 2011
    Posts: 6

    sbtslick
    Member
    from Washington

    The cause of the notorious “Piston Slap” unlike the more common “Rod Knock” (bad bearing)


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  9. Jethro
    Joined: Mar 5, 2001
    Posts: 1,562

    Jethro
    ALLIANCE MEMBER

    Looks like it had a little"kiss" too
     
  10. Deuces
    Joined: Nov 3, 2009
    Posts: 19,740

    Deuces
    Member
    from Michigan

    That piston is nothing more than a .125" over 283 piston...
    Egge probably sell those....
     
  11. Dirty30Dodge
    Joined: Jan 10, 2009
    Posts: 538

    Dirty30Dodge
    Member
    1. Upholstery

    Ok Thanks - I was under impression it was a specific piston for the 302 stroker only. They are pretty expensive. If it's just a 283 piston then it's just another piston.


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  12. Sure, bring it over I'll weld it up. I'll also strongly advise that you do Not try to use it again in a motor. In the over all cost of building Cars the cost of pistons is relatively Cheep.
    The Wizzard
     
    Just Gary likes this.
  13. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,116

    dreracecar
    Member
    from so-cal

    The cast material being of this age and being run has sooooo much contamination inbeded into the material that the weld becomes garbage and pitted, welding the crack will expand the alu and then when it cools will shrink it more then when it was expanded
     
    clem, Black Panther and Pist-n-Broke like this.
  14. DDDenny
    Joined: Feb 6, 2015
    Posts: 14,635

    DDDenny
    Member
    from oregon

    That is even pre "MO" 302!
     
    Deuces likes this.
  15. Jimbo17
    Joined: Aug 19, 2008
    Posts: 3,786

    Jimbo17
    Member

    This is a bad idea to even consider doing.
    You have to know when to say forget it!!!
    Jimbo
     
  16. RMONTY
    Joined: Jan 7, 2016
    Posts: 2,177

    RMONTY
    Member

    Burt Munro would weld it up....and go over 200 mph with it!
     
    Atwater Mike, clem, Torana68 and 4 others like this.
  17. jimmy six
    Joined: Mar 21, 2006
    Posts: 8,516

    jimmy six
    Member

    In my day a .125 over 283 was a 301...;)
     
  18. Dirty30Dodge
    Joined: Jan 10, 2009
    Posts: 538

    Dirty30Dodge
    Member
    1. Upholstery

    Thanks! Glad I had noticed the crack before I tried to sell them. Paper weights, trophy art 4 sale lol like you guys don't have a few of these laying around lol thanks


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  19. Same bore/stroke as the 302 Z motors. Chevy didn't want it to look like the hot rodders came up with it years before they did, so they upped the 301.? to 302. LOL
     
  20. NO! And even if you did the skirts look like they're trashed anyways.
     
  21. DDDenny
    Joined: Feb 6, 2015
    Posts: 14,635

    DDDenny
    Member
    from oregon

    Yeh, at 8000 rpm what possibly could go wrong!
     
  22. R Pope
    Joined: Jan 23, 2006
    Posts: 3,309

    R Pope
    Member

    New SBC cast slugs don't last long enough!
     
    Atwater Mike and Deuces like this.
  23. Deuces
    Joined: Nov 3, 2009
    Posts: 19,740

    Deuces
    Member
    from Michigan

    Same thing!.....;)
     
  24. Mr48chev
    Joined: Dec 28, 2007
    Posts: 28,551

    Mr48chev
    ALLIANCE MEMBER

    Well you can do like a buddy of mine did with hundreds of them in his shop. pull the rigs off smash them from the side, take out the steel piece and sell the broken pieces for scrap by the five gallon bucket load. He did it because it paid a few cents more a piston when he hauled a load of scrap. With the skirts scuffed up like that the decorative item thing might be the other way to get a buck or two.
    Genuine .125 over 301 Piston from the late 50's for use as a paperweight.
    In the early 70's you could buy a 302 Chevy block from Chevrolet for around 300 bucks that was a new 302 block with Z28 pistons fitted to the bores I helped a friend in Texas put one together and it ran like a bandit. He used a 283 crank and rods along with a pair of 202 camel hump heads. He had less than 500 1973 dollars in that engine when it was done, new cam lifters and all.
     
  25. Ya, but only once!
    The Wizzard
     
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  26. oldolds
    Joined: Oct 18, 2010
    Posts: 3,130

    oldolds
    Member

    offerings to speed.jpg
    Some of Burts pistons. From World's Fastest Indian
     
    Unkl Ian and Deuces like this.
  27. woodiewagon46
    Joined: Mar 14, 2013
    Posts: 1,798

    woodiewagon46
    Member
    from New York

    Anything can be welded, but why would you even think of building an engine with a repaired piston. I wouldn't trust it. If it lets go think, of the consequences.
     
    Deuces likes this.
  28. saltflats
    Joined: Aug 14, 2007
    Posts: 10,612

    saltflats
    Member
    from Missouri

    That must of been a tough piston, most that I have seen, the skirts are laying in the pan.
    Take it to your local fair and have that guy that welds up those soda cans do it for you. :D
     
    Deuces and X-cpe like this.
  29. I would like to have a set of .020 or .030 oversize 302 pistons. so I could bore a small journal 327 block and use a 283 crank. A famous engine builder once stated if you can turn a 1000 RPM more than everyone else. All other things being equal you will beat them. I suppose I will just use the 327 pistons I already have. 327 pistons 001.JPG 327 pistons 002.JPG
     
    Deuces likes this.
  30. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,682

    56sedandelivery
    ALLIANCE MEMBER

    301= pi as 3.14.
    302= pi as 3.141590265359 (although it can be taken out to 1 million digits).
    take your pick, it's only math. They both had a 4 inch bore block.
    Really old cast pistons, and the first design small journal rods also.

    I am Butch/56sedandelivery
     

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