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.

Bad harmonic balancer *Update*

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by PetaKane, Feb 2, 2003.

  1. PetaKane

    PetaKane 1/2 ton status

    Joined:
    Apr 17, 2002
    Posts:
    530
    Likes Received:
    0
    Location:
    Oklahoma City OK
    Okay I'll be honest about what I did. This was back in Sept and I really didn't know any differant, I put on my harmonic balancer on my new motor with the help of a hammer. I was very gentle, okay I wasn't gentle. /forums/images/graemlins/eek.gif I've been searching on here and I'm thinkin that maybe I've messed up the thruster bearing(s) on the crankshaft?? How hard is it to replace a thrust bearing? The engine knocks and it sounds like it is coming from the very front. I know now for sure that I'll need a new balancer, but I'm worried now that I'll need a new crankshaft. Is that a job that means pulling the whole motor out? Sorry for all the questions just don't know what to do anymore.
     
  2. DesertDueler

    DesertDueler 1/2 ton status

    Joined:
    May 23, 2001
    Posts:
    3,106
    Likes Received:
    0
    Location:
    Phoenix, AZ
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    I balancer that has come apart(like in two pieces) can make a knok at idle, but if it is still in one piece, then its not the harmonic balancer. You probably did ruin the thrust bearing. You need to pull the crank out to replace them, and yes it is easier to have the motor out. You could probably do it with it in, but is going to be a hassle.

    Dan /forums/images/graemlins/burb.gif
     
  3. 4DiggerDan

    4DiggerDan 1/2 ton status

    Joined:
    Feb 2, 2003
    Posts:
    103
    Likes Received:
    0
    Location:
    Montucky, USA
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    Its unlikely that you'd have an engine knock caused by a harmonic balancer. If you can spin the crank over with the help of a big ratchet on the end of the crank and the balancer isn't rubbing on anything, then its not your problem. You really shouldn't install a harmonic balancer with a hammer (they make a tool to do that.) A crank does take a beating driving it around, however... You ever notice that when you walk into an engine machine shop you see all the crankshafts standing on end?? Lots of machinist think that laying them on their side will cause them to bend. A bad thrust bearing wouldn't really make a knocking noise either, I've seen engines with .030" of crank play (front to back) and they weren't making any knocks. In a Chevy small block the thrust is the main bearing all the way in the back of the engine.

    Could you be a little more specific about your knocking sound? Does it do it at idle, under load, both, just at one RPM??? Is it a knock, or tick? Was it always there, or just turn up?

    When all else fails, go back to your engine machine shop and ask them to give a listen. If its a reputable shop they'll be more than glad to help you out. Big production shops that sell engines on the 'net and out of parts stores (like Checker or NAPA) are usually some of the worst to deal with if you have a problem.
     
  4. PetaKane

    PetaKane 1/2 ton status

    Joined:
    Apr 17, 2002
    Posts:
    530
    Likes Received:
    0
    Location:
    Oklahoma City OK
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    I wish I could describe the knock better. Tomorrow I'll go start it up and listen. I noticed that the balancer was wobbling around like crazy and I don't think that is good at all. Maybe it's normal for them to wobble a little but this was crazy lookin. So I got nervous and shut it off I thought the damn balancer was gonna fly off. The first thing I'm gonna try is a new harmonic balancer. Should I get an 8" or 6 3/4"? If the new balancer doesn't work I'm thinkin of just gettin a new shortblock since I know that I'm not skilled enough to put a new crankshaft in.
     
  5. 79k20

    79k20 1/2 ton status

    Joined:
    Oct 15, 2001
    Posts:
    144
    Likes Received:
    0
    Location:
    s.e. kansas
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    On my truck the little key the balancer presses onto was worn. It caused the balancer to bounce around and sound like an engine knock. A bigger key and new balancer fixed it. The crank wasn't hurt at all.
     
  6. PetaKane

    PetaKane 1/2 ton status

    Joined:
    Apr 17, 2002
    Posts:
    530
    Likes Received:
    0
    Location:
    Oklahoma City OK
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    I seriously hope that my problem turns out like yours. I've got way too many other things to worry about right now, having to do serious motor work is just gonna make me lose all interest in this piece. Also is there a difference in the 8" and 6 3/4" balancers other than size? I'd rather get the better one if there is one. Thanks again
     
  7. POWERMAD

    POWERMAD 1/2 ton status

    Joined:
    Mar 4, 2001
    Posts:
    3,466
    Likes Received:
    0
    Location:
    Oregon
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    I have replaced cranks without pulling the engine before.
    and I don't know how many bearings I have replaced with the engine in the rig. Any plant that blows a head gasget and coolant gets mixed with the oil I roll new bearing in.
    You need to determine if the thrust bearing is bad first.
    Unless you were brutal with the hammer it "should" be ok.
    Don't hit the panic button just yet, check the rest out too and get a better idea where the noise is coming from.
     
  8. 4DiggerDan

    4DiggerDan 1/2 ton status

    Joined:
    Feb 2, 2003
    Posts:
    103
    Likes Received:
    0
    Location:
    Montucky, USA
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    No, the only difference is the diameter. Yours should be an 8". While you're at the parts store, get a balancer installer tool /forums/images/graemlins/smile.gif Inspect that woodruff key too while you've got the old balancer off (the thingy on the crankshaft that indexes into the slot milled inside your balancer)
     
  9. PetaKane

    PetaKane 1/2 ton status

    Joined:
    Apr 17, 2002
    Posts:
    530
    Likes Received:
    0
    Location:
    Oklahoma City OK
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    Ron, how do I check to see if the bearing is bad? Is it simply a matter of removing the oil pan, or is there something else? Thanks alot everybody
     
  10. Thunder

    Thunder 3/4 ton status

    Joined:
    Jul 20, 2000
    Posts:
    8,946
    Likes Received:
    1
    Location:
    Northeast Nevada
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    I dont think it is the thrust bearing. If your balancer is wobbleing around that should give a pretty good clue as to where the problem is. It should run straight and true. Replace the balancer.
    The reason you are not susposed to install them with a hammer is because it can and usually does ruin the balancer.
    Get the installation tool, Or a longer bolt and some washers and press it on that way.
    Check to make sure the woodruff Key on the crank is not ruined or wore. It should have a nice tight fit in the balancer.
    Make sure to torque down the crank bolt to specs also.
     
  11. mudrunner78

    mudrunner78 1/2 ton status

    Joined:
    Sep 7, 2001
    Posts:
    366
    Likes Received:
    0
    Location:
    Rocksprings, TX
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    hey don't feel bad did the same thing, but alittle worse first the chain on my hoist broke as I was moving the engine into the garage at 3am, then the next night I tried to install and started hammering on a block of wood. Well the balancer wobbles pretty bad, no knock thou. I figure I am just going to pull the motor and check the specs if I can't figure whats wrong I am taking mine to a machine shop I figure they will not charge to much to find the problem. I am here with you, just sometimes I get in a hurry and it cost me more money. Jesse
     
  12. big pappa b

    big pappa b 3/4 ton status

    Joined:
    Jan 3, 2003
    Posts:
    6,328
    Likes Received:
    0
    Location:
    Falcon, Colorado
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    Check all the bolts holding on your pulleys. Also try listening to water pump, alternator, ps pump, ac etc. Could have bearings going bad in one of those. Hard to say for sure unless I actually heard the sound
     
  13. 79k20

    79k20 1/2 ton status

    Joined:
    Oct 15, 2001
    Posts:
    144
    Likes Received:
    0
    Location:
    s.e. kansas
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    I think the only difference is different years had different diameters.
     
  14. POWERMAD

    POWERMAD 1/2 ton status

    Joined:
    Mar 4, 2001
    Posts:
    3,466
    Likes Received:
    0
    Location:
    Oregon
    Re: What are the chances a bad harmonic balancer is makin my engine knock?

    From the sounds of it the balancer is junk.
    For an installation tool I just use a 4" grade 8 bolt and run a die down to the head.
    then thread a nut all the way up it. use the big flat washer with some grease on both sides and thread the bolt into the snout.
    Hold the bolt with a wrench and run the nut down till the balancer is seated.
    You stand a good chance of stripping the threads out of the crank if you just use a bolt and try to power it on.
    if you still have a knock check that your flywheel cover isn't hitting the flywheel or something.
    If that aint it drop the oil filter and cut it open and see if there is any metal in it.
    If it looks like alot then you are going to have to drop the pan and have a look see.
    You can short the cylinders out too and see if the knock gets quieter when you pull off a plug. That will narrow it down some.
     
  15. PetaKane

    PetaKane 1/2 ton status

    Joined:
    Apr 17, 2002
    Posts:
    530
    Likes Received:
    0
    Location:
    Oklahoma City OK
    Once I got to pullin the balancer off, I found the problem right away. The 3 threaded holes that hold the crank pulley on had been stripped out, and the big bolt was barely hangin on. So I got a new balancer and cleaned out the threads on the crankshaft and got a new bolt. No more knockin sound. Thanks to all who helped out.
     
  16. K5on38s

    K5on38s Registered Member

    Joined:
    Dec 11, 2002
    Posts:
    90
    Likes Received:
    0
    Location:
    Buffalo, NY
    Good to hear you solved your problem. i just had one Question, how much lift do you have? the truck looks awsome /forums/images/graemlins/thumb.gif
     
  17. PetaKane

    PetaKane 1/2 ton status

    Joined:
    Apr 17, 2002
    Posts:
    530
    Likes Received:
    0
    Location:
    Oklahoma City OK
    Thanks,,it was 12" susp in the pictures, on 40's. Now it's down to 8" on 44's with alot less fender /forums/images/graemlins/smile.gif I'll try to get some new pics up soon.
     

Share This Page