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Discussion Starter #1
Been tapping on balancers for decades now, NEVER had one come off....

as in somehow, back out the bolt, work it's way forward, and wipe out the seal and maybe even the timing cover.....

ever once, unheard of....

anyone EVER heard of this happening....on ANY car???

I can understand some wild theory of maybe why...but in reality???

:crazy: :surprised :WTF
 

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Nope, never heard of a specific case. Seen several delaminate or slip
 

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I know someone who recommended you move the balancer out to line up your pulleys....very well respected at ...well you know who..and where
.....redvetracr
 

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I had the bolt for the Harmonic balancer shear off on a Chevette my Dad owned. He was convinced I had been racing the car.

Dad..... a CHEVETTE? C'mon....
 

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Ive even ran one WITHOUT a bolt for a while. 3 years actually. Sold it that way. The threads in the crank were stripped out and it was an old truck so I didnt care. I just beat it on and that was that. I do know that beating one on as opposed to pulling it is murder to you thrust bearing. Oh well :nuts:
 

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the early years (55-60's, i was there but can't recall exact dates anymore) didn't even have threads in the crank for a retaining bolt...and those short stroke ''small blocks'' with solid lifters would rev 8k with very minor mods...nobody ever lost a h/b
 

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I had the bolt for the Harmonic balancer shear off on a Chevette my Dad owned. He was convinced I had been racing the car.

Dad..... a CHEVETTE? C'mon....
HEY I made a bunch of $$ drilling out those broken crank bolts in those things. Had a left twist drill bit and a right angle drill that was MADE for that job. Got paid 8 hours and spent about 3 hours drilling and putting the front of the engine back together.


On a SBC, the crank is tapered and an interference fit. Hopefully it's fully seated at the same time the balancer gets against the crank gear. That's why the bolt's there I bet. I've seen Chevy 6 cylinder balancers walk off and make a heck of a noise.
 

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Discussion Starter #11
HEY I made a bunch of $$ drilling out those broken crank bolts in those things. Had a left twist drill bit and a right angle drill that was MADE for that job. Got paid 8 hours and spent about 3 hours drilling and putting the front of the engine back together.


On a SBC, the crank is tapered and an interference fit. Hopefully it's fully seated at the same time the balancer gets against the crank gear. That's why the bolt's there I bet. I've seen Chevy 6 cylinder balancers walk off and make a heck of a noise.
Tim, your SURE about that?? I did notice for sure the SBC balancer is sure as hell tight on that snout, but it presses on the whole way tight, snug as hell, not like any morse taper I ever messed with....the olde tyme Pontiac engines it just slipped on and off easy, held by the bolt and the woodruff key...

I never did understand that if Poncho was happy with a slip fit, why Chebby would not be....makes NO sense to me....

so much so that one of these daze I just may take a brake hone to the balancer and do a Poncho slip fit just to prove my point....
typical **** that drives me crazy......:crazy: :rolling: :WTF :cheers:
 

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I had the outer ring break free of the inner when the rubber let go. The outer ring made it's way back against the timing cover, burned a nice arc on the metal. I never noticed because at the time I was running the big three-groove pulley that hid all this from view. I was probably close to hearing and smelling it though.
I have never heard of one backing off (moving forward).
Have you changed any accesories in your drivebelt system?
 

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Discussion Starter #13
Actually I fess up, it's on a 350 chebby boat I was working on, the guy went out on 4th/evening to watch city Fworks display off the river, and got stranded so I am getting 3rd hand information as to what went rong, it was a 8" blancer on there, and so anything ELSE that can go rong?? sorta getting tired of this, and the guys were asking me to get some intelligent information about chebby balancers, which apparently that outer ring I bet walked forward not rearward....can't figger WHY, just must have....

I never have ever heard of a harmonica balancer coming off the snout....
 

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the early years (55-60's, i was there but can't recall exact dates anymore) didn't even have threads in the crank for a retaining bolt...and those short stroke ''small blocks'' with solid lifters would rev 8k with very minor mods...nobody ever lost a h/b
There was a special service tool that clamped the inner hub and outer ring together to facilitate hammering them on. I have a pic of it in one of my GM service manuals. This supposedly prevented damage to the balancer.
 

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Been tapping on balancers for decades now, NEVER had one come off....

as in somehow, back out the bolt, work it's way forward, and wipe out the seal and maybe even the timing cover.....

ever once, unheard of....

anyone EVER heard of this happening....on ANY car???

I can understand some wild theory of maybe why...but in reality???

:crazy: :surprised :WTF
It can happen ...

A long time ago, when I was a younger man (not any wiser, just younger), a good friend of mine had a '74 Z28 that he acquired used. The claim from the seller was that the engine had been rebuilt using really good parts, well respected builder, all that yadda yadda.

He'd had the car for several months, and we elected to attent the Gatornationals along with some other friends.

I lived near Savannah, GA at the time, so the trip was just a few hours. However, it was the first extended trip he'd taken the car on.

About two hours into the trip, we had to pull over because the engine had thrown a belt. If the ominous music had been playing in the background, I might have picked up on what was happening, and that bad things were going to happen. However, no ominous music, so we replaced the belt and went on our way.

Saturday evening, we were driving around Gainesville having a good time, when there was a horrendous noise from the engine compartment, along with the sight of escaping coolant (smelled like it, too!). When we pulled over, there was a trail of coolant and oil left behind. There were also some parts left sitting in the road.

The main part was what was left of the harmonic balancer (all of it - not just the outer ring).

The balancer walked off the end of the shaft.

We towed the car home on Sunday.

When we pulled the engine, we removed the crank and found the problem. The crank snout wasn't straight, and the balancer had been unbalanced since the previous owner had built the engine. By unbalanced I mean that the balancer wasn't rotating about the same axis as the rest of the crank, and it set up an oscillation that allowed it to walk off the end of the shaft.

This explained why we threw the belt on the way down - the balancer had begun walking off, and caused misalignment between the pulleys. It was enough to throw the belt, but no one was really looking for imminent failure of the balancer (I didn't have that ominous music to go by!).

Steven
 

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Discussion Starter #17
Balancer needs be hammered tight, up against timing gear...never seen an engine that din't do that....

BTW, finally got a good description of the exact nature of failure....

the balancer is small diameter 6"?.....and so the large diameter will not work apparently...

second off is that balancer on there broke around the collar of the piece fitting over the crank snout....how to describe....the center section was split from the rest of the balancer....and NO not the rubber ring...the part the seal would ride against, broke at the flange.....

go figger.....:crazy: wonder if it was hit on too hard to get it home on the crank, and so the metal was broken, then failed....

damn boat is enough to drive us nutz....
 

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