Loose/broken harmonic balancer - and more

[cptmoney]

So the '77 K10 I've been working on has a super loose, clunky harmonic balancer.

PO said he heard a squealing noise, so he yanked the belts/lower pulley, noticed it was crazy loose - and parked it right there, assuming the worst.

Worst being.....broken crankshaft? Ruined key slot?

Any ideas?

The center bolt is gone; would that keep the harmonic balancer from being so crazy wobbly/clunky?

I've never heard the truck run, and PO said it has been years (5 or 6) since all of that happened. I'm expecting the worst, and have planned accordingly - but before I start stripping her down for the engine pull, I want to make sure that there's nothing obvious that I've not tried...

Any ideas? Sounds pretty bad, in my book. Pics coming up....

 

[cptmoney]

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[cptmoney]

Can't tell much from the pics, other than a peek into the bolt hole in the center of the balancer.

Anything obvious that you can see?

 

[PrairieDrifter]

Pull the balancer, inspect the crank and balancer, inspect the keyway. I would just go ahead and get a new balancer right away if the crank looks okay, then install the new one with the centerbolt actually installed lol. And see if it fixes the "problem" and then go from there.

 

[HotRodPC]

Have you started it up to listen to it for yourself? Usually a balancer doesn't make noise when bad. Does it look like it has spun on the rubber? It doesn't appear so in the pics but it's hard to tell. I had one that slipped about 1/3 of a turn. Never made noise.

 

[cptmoney]

I've not started it up at all, and it's been years since she's been fired up. I can't tell if it has "spun" or not. It lifts up/down and in/out just enough to make a good "clunking" sound....maybe 1/16" of movement, give or take, in all directions. Might be a shade more than that.

Are all balancers the same? Do I just need to walk into my local parts shop and ask for a small block harmonic balancer? What about the center bolt? Mine is missing (came to me just as you see it), so are they easy to find? Or do I need to run down the salvage yard and scout around until I can find one? I have no lower pulley either, so I'll have to chase that down also.

Do I need a puller to get this thing off? Can I remove it while the engine is sitting right in the engine bay? Or will I need to yank the radiator to create enough space to make all this happen?

Can you tell I've never done this before?! All these questions! Hahaha!

Hey - thanks a million for the help; you guys are lifesavers.

 

[HotRodPC]

You mean you can physically move it and hear it clunking? Never heard of that before. Sure hope it's the balancer moving and not the crankshaft.

 

[74 Shortbed]

I've seen that before on big blocks with factory balancers, if it's been that way for a while it's probably egged out by now, need to get that off now before it comes off going down the road, they're just like a buzz saw when they fly off..

 

[cptmoney]

I'm not driving it, so everyone is safe - for now! Haha

I'll see if I can get it off.... Then, if the nose of the crankshaft moves - what next? We'll know she needs major surgery, correct? If it's not loose, then maybe the balancer was just improperly installed? Maybe? Would I ever get that lucky?

 

[HotRodPC]

That's what I'm wondering. If it's not the crank moving around. That would be bad for sure. Certainly a sign the main bearings are junk and/or the crank is broke.

 

[74 Shortbed]

Somebody didn't torque the bolt right. If the crank was broke the snout would be gone and so would the balancer, what could have happened though is it sheared off the woodruff key, if it did that the snout could be damaged but maybe it could be dressed up, but won't know that till the balancer is off.. Also it's possible the snout is bent now, especially if it's a cast crank.

 

[cptmoney]

Can I just swing by the boneyard and grab a crank pulley, balancer bolt, and a used balancer? Is that a quick "grab and go" setup?

On another note, what if it broke on the inside of one of the main bearing journals? Wouldn't that hold the broken crank in place?

 

[74 Shortbed]

If the crank was broke inside you wouldn't be running it. I wouldn't mess with a used one, factory ones aren't expensive.

 

[cptmoney]

Well, I'm not running it. At all. Been years since she was fired.

This is just how she came to me: missing crank pulley and pulley bolts, missing balancer bolt and washer, and sloppy balancer.

Looks like a new balancer at the local parts shop is about $50, and another $12 for the bolt. I'll grab a pulley and pulley bolts from the local salvage yard if I need them.

Right now I'm going to focus on getting the balancer off to determine just what's going on..... Not sure if I can do this while it's still in the truck - but hopefully I can get it done. May have to yank the radiator and fan shroud, but it should be doable.

Somebody took the time the remove the pulley and crankshaft bolt, that's why I'm expecting the worst. At some point someone starting digging into the mess and decided to abort. I'm guessing they were scared off by what they found - as I may be as well! Haha

 

[HotRodPC]

Yes you can get the balancer off with a puller with the engine right where it's at.

You never know what happened here. It could have been some guy that didn't know his ass from a hole and pulled the bolt and pulley and thought he could get the balancer off and beat it with a hammer to get it off not knowing you're supposed to use a puller and then gave up on it and walked away. I've seen it happen for other situations.

My bro once bought a car where a kid did his own tune up. He pulled all the plug wires off and replaced with new. He was warned and told, DO NOT forget #1 is, from there just put them back on in order and you'll be fine. He remembered where #1 was. Then put them on IN ORDER, 1, 2, 3, 4, 5, 6, 7, and 8. I mean, that makes sense right? Poor kid gave up on it knowing he had it all right and checked it and triple checked it and it was right. He played and played with the points thinking that's what he did wrong.

I looked at the engine and did a compression check, checked the trans fluid on it before I told my bro to buy it and told my bro it probably jumped time and needed a timing chain. Didn't think to look at firing order at the time but it was burping and farting all over the place so I figured timing chain but it was cheap enough so I told my bro to buy it. After paying the cash, and the kid telling the story, that it was running fine when he did the tune up and it never ran since, it made me think to check the points. They were out of whack. Fixed that. Then going with the basics, checked the firing order and about ****. Set it to 1 8 4 3 6 5 7 2, the car was running within 2 hours of my bro owning it.