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Technical Harmonic balance nightmare

Discussion in 'The Hokey Ass Message Board' started by Karl M, Sep 25, 2018.

  1. Karl M
    Joined: Jul 19, 2017
    Posts: 119

    Karl M

    And than there is the motor/engine terminology. {Motor -electric}...{engine- 350, 283....}
     
    badvolvo likes this.
  2. You say you "saw" a vibration in the dampener... Do you also "feel" a vibration when the engine is running? :confused:
     
    tommyd likes this.
  3. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    I know that it's a dampener , but why do some aftermarket cranks come internal/ external balance , meaning the damper is neutral bal. And the flywheel is weighted (offset) balance if the damper is not also a balancer..
     
  4. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    Crankshaft will actually twist back and forth, up around 2°, the damper resists torsional vibrations, I believe the heavy outer steel weight leads and lags a bit. Or is supposed to, once the elastomeric dries out it slips. Cracks can develop or, even the crankshaft breaks. There is a specific RPM (or RPMs) where the crank achieves what is called resonance. That's when the trouble starts. That's why they are sometimes called harmonic balancers. Seems to me this would beat the hell out of main bearings too, rear main seal oil leaks, and probably other bad stuff.
     
    pitman likes this.
  5. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    One definition of "balance" in the Oxford dictionary is "A counteracting weight or force", which is pretty much a dead-on description of a damper, so let's not get our panties in a knot when someone calls it a balancer.

    I've read that a Buick Straight 8 crank can twist up to 7°. Not sure if the source was accurate but it must have been because it was on the internet. 7° seemed like an awful lot of twist to me.
     
    Truck64 likes this.
  6. BJR
    Joined: Mar 11, 2005
    Posts: 9,817

    BJR
    Member

    I know this is a traditional site but what about the PC gender neutral or non traditional genders out there?:eek: How will they get the right part? :p:D
     
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  7. s55mercury66
    Joined: Jul 6, 2009
    Posts: 4,335

    s55mercury66
    Member
    from SW Wyoming

    Early Top Fuel Hemis would twist up to 18 degrees, and cams were indexed to take that into account. Pretty sure my SBC's don't quite get there.
    I had a friend, RIP, who had a 327 in a '65 Chevelle 2 door wagon, the balancer/damper/dampener of which kept falling off. He refused to tap the crankshaft for a bolt, and just let the car sit. The results I posted in the "sitting and rotting" thread back in 2012, or thereabouts.
     
  8. Atwater Mike
    Joined: May 31, 2002
    Posts: 11,625

    Atwater Mike
    Member

    Yeah... Like 'anyways'... Hate that! Any one way is the meaning. ANY way. Like...take your pick. How many ways can you go at once?
    Don't get me started...:D
     
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  9. Atwater Mike
    Joined: May 31, 2002
    Posts: 11,625

    Atwater Mike
    Member

    Just a note here...My friend Johnny Miller (commercial airline pilot) had a nice little '58 'Vette he bought cheap, had the young street racer next door re-assemble the 283 for him, short block was in chassis, everything else in the trunk...
    Engine smoked some, I told he should have majored it. "No, just because I got it cheap didn't mean pouring $$ into it..."
    The vibration was quite noticeable, so I 'shook it down'...(engine off, grabbed damper and turned it back-and-forth...Damper was tight on the crank, but the crank had 'play', indicating a broken crankshaft.
    Johnny was in such denial that I removed the pan...the break was at the #6 crankpin, obviously turned with a sharp stone, removing the radius...Yep. Con rod brgs: .030.
    This was in 1966, Johnny bought a new short block, from the Chev dealer...
     
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  10. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    Irregardless, it's a mute point.
     
    pitman, scotty t, jbrittonjr and 7 others like this.
  11. How bout we call it "big round thing" on the crank snout?
     
    jazz1, Truck64 and egads like this.
  12. 1934coupe
    Joined: Feb 22, 2007
    Posts: 5,051

    1934coupe
    Member

    Truck64 you have a way with words. Regardless of what others say.

    Pat
     
    loudbang likes this.
  13. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    I wonder if maybe they mean +/- , for a total of X°? It would be cool to see some high speed recordings of the twist. There's some interesting valve spring action at high RPMs so ...
     
  14. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    I guess that's a compliment. Thanks
     
    loudbang, 1934coupe and dirty old man like this.
  15. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    squirrel wrote -
    probably because so many folks use the wrong term, they have to go along with it...

    Every now and again...someone's gotta "try" to get things on the right track.
    OR. did Forrest Gump have it right ?

    Mike
     
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  16. squirrel
    Joined: Sep 23, 2004
    Posts: 55,942

    squirrel
    Member

    yup...I try by setting a good example, I don't worry too much about trying to change the world. I know I can't do it.
     
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  17. Deuces
    Joined: Nov 3, 2009
    Posts: 23,754

    Deuces

    You sure it's welded on and black silicone???
    Sbc cranks sometimes leak out of the crank snout bore because of a gap in the keyway....
    Or how about a sheared keyway in the dampner bore or the wrong flywheel/flexplate....
    Just thinking out loud here....
     
    loudbang likes this.
  18. Nah... that would be too easy, Maybe JB Weld..
     
  19. Timehunter
    Joined: Sep 5, 2018
    Posts: 3

    Timehunter
    Member

    A little more nit-pickn…….
    The speedy sleeve was for where the seal surface area was worn.
    Used so your timing cover seal would work.
    It had nothing to do with holding the "big round thing on the snout" onto the crankshaft.
     
  20. Karl M
    Joined: Jul 19, 2017
    Posts: 119

    Karl M

    OK, going to try and post some pictures of the welds just for posterity sake or a good laugh! The blobs you see are not grease globs, they are welds!
     

    Attached Files:

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  21. saltflats
    Joined: Aug 14, 2007
    Posts: 12,594

    saltflats
    Member
    from Missouri

    That looks rough.
    If I didn't want to get inside the engine, I would cut the inertia ring off and see what happens.
    Anything after that will be a true test of will.
     
  22. squirrel
    Joined: Sep 23, 2004
    Posts: 55,942

    squirrel
    Member

    get a hole saw that will just fit into the hole in the damper, and carefully cut the welds.

    Then you can take the engine apart, and discover that you have to replace everything, anyways.
     
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  23. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,603

    Johnny Gee
    Member
    from Downey, Ca

    Pull crank with timing cover and leave the hole saw alone then.
     
  24. Karl M
    Joined: Jul 19, 2017
    Posts: 119

    Karl M

    Well that is what I am afraid of. Waist time on this when the engine needs to be replaced anyway. Can't see the welds with out a mirror. I would have to pull the radiator and possibly the grill to get at the welds. If I had the skill set and $ I would replace the engine.
     
  25. 1934coupe
    Joined: Feb 22, 2007
    Posts: 5,051

    1934coupe
    Member

    Karl it might not be all that bleak, those welds look like shit and you might be able to break them off or like has been said using a hole saw without the pilot break them and then using a quality puller threaded all the way into the damper/balancer pull it off. I'm afraid you are going to pull the radiator and grill anyway.

    Pat
     
    Johnny Gee likes this.
  26. arthurC3
    Joined: May 20, 2005
    Posts: 130

    arthurC3
    Member

    I concours,totally.

    Sent from my LG-H830 using The H.A.M.B. mobile app
     
    jazz1, Truck64, K13 and 2 others like this.
  27. Terrible80
    Joined: Oct 1, 2010
    Posts: 785

    Terrible80
    Member

    I agree, in fact a puller might work without any cutting or grinding. Those half assed welds aren't very strong.

    Sent from my LG-TP450 using The H.A.M.B. mobile app
     
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  28. squirrel
    Joined: Sep 23, 2004
    Posts: 55,942

    squirrel
    Member

    looks to me like the welds are better on one side, than the other, which is not surprising...you'd have to turn the engine to get it into position to get a good weld on the other side, and whoever did this "repair" was probably too lazy to do that
     
    saltflats likes this.
  29. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    Hell, one "glob" is already broken.

    Just try using a good puller, might just come off. Put pressure on the puller, smack the pullers shaft with a good sized steel hammer, more pressure, another hammer whack and stand back.

    Mike
     
    Johnny Gee likes this.
  30. 34toddster
    Joined: Mar 28, 2006
    Posts: 1,482

    34toddster
    Member
    from Missouri

    I'd bet the crank snout is junk if they welded it on. I'm speaking from experience, my tight assed buddy that would never buy a new Damper had the task welding his on at the Street Rods Nats in St Paul many years ago
    After driving many more miles he decided to build a new motor for his car and was dreading removing the welded on part, tapped it with a hammer and it came right off, looks like your will also.
     
    luckythirteenagogo likes this.

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