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are these important?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Seventy4Blazer, Sep 10, 2002.

  1. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    the little tabs on pistons... i have a "made in mexico" 350 that has the dipstick on BOTH sides and a 2 part rear main.
    thing is i got the motor back in 97. it had less than 10k on it. when i pulled it in late 2000 it had about 60k on it.
    i ran the PISS out of it. well i started to pull her apart tonight and only to find that the number 2 piston has the outter tab broken off....
    i plan on running it, and running even more piss out of it(some day when i put the blazer back together) but i was just wonderin HOW important are they? they being the tabs...
    grant
     
  2. yeild2me

    yeild2me 1/2 ton status

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    Are you talking about the skirt? its been a while since i have been inside a 350, but i believe that is what you are talking about. If, its broken off *any* the right thing to do is replaace it, but you could prolly still run it, esp. if you have no money in it and dont care if it decides to let go at anytime. The biggest problem i can see (Although i am no professional engine builder) is it being out of balance.

    How did it break in the first place? If you broke it on disassembly, thats one thing, but if something in the motor caused it to break, thats another!!!


    hope this helps, maybe someone has a little more info for ya.

    rob
     
  3. jimmyjack

    jimmyjack 1/2 ton status

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    Sounds like a skirt. I think a plain jane stock piston is only about $8. I dunno if you can just buy one though. For what it's worth I'd replace it.
     
  4. Sandman

    Sandman 3/4 ton status Author

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    You can just replace the piston and should be able to get away with it. I have on my old 400 with no problems.
     
  5. chevyracing

    chevyracing 1/2 ton status

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    If the skirt broke chances are the wrist pin is seizing up. You need to replace it. When you do make sure you check the cylinder for out of round and tolerances. Put a round piston in an oval cylinder and you could be asking for a lockup. Also if the skirt broke off you have a bunch of nice little particles running around inside of there as well just waiting to plug an oil galley.

    John
     
  6. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    all the pieces were in the scree on the pump. the dang thing broke on its own. i might change out pistons, but im not sure. if i run this motor for a few months(once i get the dang truck back together) then i will build a BB for it. then i will run the piss out of it and try to blow it.... he hehe...
    im not that worried about it. if it goes it goes. i have a few 350 blocks laying around. i can spare one.
    maybe ill replace it, but if i do ill replace the rod also, and if i do that might as well do them all. then i might as well machine the block... see where that goes... /forums/images/icons/frown.gif /forums/images/icons/shocked.gif
    i did it by hitting 8k to many times......(its a stock motor for the most part)
    grant
     
  7. TopOff

    TopOff 1/2 ton status

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    Wouldn't there be balancing issues to deal with???

    I would think if this piston is out of balance, the bearings will get shredded...

    I know it matters on my 383....
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Thats an interesting point. Not sure how the remanned engines are, but on this motor I'm building (still) when I had it balanced for the hypereutectic pistons, they had to take a LOT of metal off of the crank to get it to balance.

    This is just a standard .030 over 350, it seems actually scary to me to put together an engine anymore without having it balanced. If its been balanced already, if you break something, a shop will actually be able to take the spec sheet from the balance job, and get the new piece balanced to the others without a whole re-balance.

    A little off topic, sorry, but I would be concerned with balance as well, especially if I needed the motor to last very long, and/or I was going to be hard on it.
     
  9. bablazer73

    bablazer73 1/2 ton status

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    Generally when an engine is "remanned" nobody cares about true balance. Only finatics and people who "care" worry about true balance. In most cases replacement stock pistons are about the same weight as the factory pistons and they don't worry about balancing. If you are using other than stock, it will make a big difference. any vibration in an engine is a killer! most stock harmonic balancers don't do much above 4,000 rpm. If this is just a beater engine, replace the piston, check the rod and continue to beat the piss out of it and save the money for the big block!! The skirts will usually brake off if the cylinder is oval shaped or taper worn. Or if over revved!!
     
  10. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    actualy this was a BRAND new crate at the time of purchase. nothing was reman.
    and as for balance on it you would be surprised.
    it has been balanced more than a lot of brand new engines. i was weighing the pistons and rods a while back(bout a year ago)
    durring a re-ring and the tolerances were DAMN close.
    grant
     
  11. m j

    m j 1/2 ton status

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    I still dont have a clue what you are saying broke off?
     
  12. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    as in busted, gone, broken, missing in action, NOT there... little chunks it becake. well not so little chunk...
    getting a picture now.
    grant
     
  13. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    disreguard that last post... i need to read slower...
    imagine a piston. it has two little things that hang down, they are the skirt.. from what i can see it keeps the piston from wobbling as much(am i right)
    grant
     
  14. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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  15. Rebel88

    Rebel88 1/2 ton status

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    that is actually a link to this very thread...

    Later
     
  16. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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  17. Rebel88

    Rebel88 1/2 ton status

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    yeah thats a broken skirt...funny story but about 4 years ago my dad and i bought a 69 impala to restore as my first vehicle...it ran a little rough when we got it but was definitely driveable so we did so...for a few months actually...

    when we finally pulled the motor it had 7 broken skirts total...they were laying in the oil pan...i dont see a problem with running it temporarily

    just be easy on it

    Later
     

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