Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

external v. internal balanced engine

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by lasvegas, Sep 23, 2001.

  1. lasvegas

    lasvegas 1/2 ton status

    Joined:
    Feb 27, 2001
    Posts:
    122
    Likes Received:
    0
    Location:
    Las Vegas, Nevada
    How do you tell if your small block is internally or externally balanced? I have the ZZ4 and do not know which it is. Can anyone help? I guess this makes a difference as to harmonic balancer, flywheel, gear drive choices . . .
     
  2. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    The only externally ballanced SBC is the 400. If you have a 383 most likely it is externally balanced (some custom cranks are internally ballanced). You can tell by the counter weight on the flywheel and the large section removed from the balancer.

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
    <a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>
     
  3. Neil

    Neil 1/2 ton status

    Joined:
    Jun 10, 2001
    Posts:
    275
    Likes Received:
    0
    Location:
    Dothan,Alabama
    ZZ4 is internally balanced.. 400 is only sb w/external &amp; will have counterweights on the flywheel and a big fat harmonic balancer..FYI..big blocks are externally balanced also.

    Neil H. Alabama.. "It's a full size thang, Jeep owners don't understand!!" '78 K5 400ci 4x4 AT,AC,PW Cheyenne., '74 C10 4x2
     
  4. muddin4fun

    muddin4fun 3/4 ton status

    Joined:
    Feb 19, 2001
    Posts:
    5,644
    Likes Received:
    0
    Location:
    N Texas
    My 383 is externally balanced and it has weights on the fly wheel. I'll have to go look at my balancer again, I think it has a notch in it er somethin.

    If you see my truck on a trailer, call 911 cause it's <font color=red>STOLEN!!!</font color=red>
    Website link is in my profile [​IMG]
     
  5. thatK30guy

    thatK30guy 1 ton status Premium Member

    Joined:
    Jan 12, 2001
    Posts:
    32,076
    Likes Received:
    55
    Location:
    .
    FYI, only the 454 is externally balanced.

    The 396, 402, 427's are all internally balanced.

    <font color=red>I'm a "black top mudder"!!!</font color=red>

    <a target="_blank" href=http://coloradok5.com/gallery/thatK30guy>http://coloradok5.com/gallery/thatK30guy</a>
     
  6. lasvegas

    lasvegas 1/2 ton status

    Joined:
    Feb 27, 2001
    Posts:
    122
    Likes Received:
    0
    Location:
    Las Vegas, Nevada
    my question comes up because the Chevy Hi-Po parts manual says that all the 86 and up one piece crankshaft seal crankshafts require a flywheel with counterweights. Is the counterweight to balance the flywheel or is it to balance the crank?
     
  7. michaelm

    michaelm 1/2 ton status

    Joined:
    Feb 2, 2001
    Posts:
    872
    Likes Received:
    0
    look in the book, if it is the chev power manual pg5-18 fig 50, and you can see the counterweight at the flywheel flange on the old style cranks. one piece seal style are round there so they moved the weight to the flywheel. i will go with you and call that external.
     
  8. lasvegas

    lasvegas 1/2 ton status

    Joined:
    Feb 27, 2001
    Posts:
    122
    Likes Received:
    0
    Location:
    Las Vegas, Nevada
    Just so you know, I e-mailed General Motors (GMperformanceparts) or something like that and they e-mailed me back that the zz4 is "externally balanced". Hopefully that does not destroy your view of the universe. They also gave me some websites for looking up technical information on GM engines if anyone is interested.
     

Share This Page