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If you have ever wondered what would happen if your harmonic balancer comes apart, look no further. Here’s all the parts I had to replace plus the coolant and power steering fluid and timing cover gasket. If it weren’t for a couple of Good Samaritans, it still wouldn’t be back together. Power steering brackets are on back order until at least February, maybe longer. 1968 BB.
It’s one of those things I never really thought about, I still don’t know how to check it. It gave no warning at all, I was just coming up through the gears at about 4500rpm and it came apart and made one heck of a noise.
That's seriously scary. If you don't have a top flight restoration maybe an SFI approved balancer needs to go on there next time. I may do that after seeing your scary mess.
It’s one of those things I never really thought about, I still don’t know how to check it. It gave no warning at all, I was just coming up through the gears at about 4500rpm and it came apart and made one heck of a noise.
Mine let go and took the water pump through the hood.......I admittedly was playing, shifting at 7000 rpms.
Now every balancer I use is SFI rated.
Was it a 55 year old balancer? never think about replacing due to age.
I’m not sure how old the balancer was. With the pulley on there it is hard to see what shape it was in. The only clue I had was that the front seal had started leaking and I am wondering if that had something to do with the failure.
Wow, I didn't know they could actually fly apart in pieces. There must be a cause to weaken the structure of the cast iron - or is it ductile iron; I wonder if it was pounded onto the crank, inadvertently creating cracks and weakening the casting.
I had one come apart at 7000+ RPM. It was an aftermarket one where the bolts holding it together came loose and you couldn't see it behind the pulley. Took the water pump off, broke a chunk off the block where the water pump mounts...and worst of all my brand new high $$$ 2hour old transmission split in half!!
I had one come apart at 7000+ RPM. It was an aftermarket one where the bolts holding it together came loose and you couldn't see it behind the pulley.
I'm thinking an entire tube of loc-tite on each bolt wouldn't be uncalled for!
Again, I'm going to confess my lack of experience with harmonic balancers, expecially ones subjected to over 7,000 rpm... I've never seen one held together with bolts; just seen the common ones with inner hub, rubber securing ring, and outer balancing cast iron ring.
Wow, I didn't know they could actually fly apart in pieces. There must be a cause to weaken the structure of the cast iron - or is it ductile iron; I wonder if it was pounded onto the crank, inadvertently creating cracks and weakening the casting.
Agree. This has to be a very rare event. 99% of them will run a million miles without an issue.
In my youth I didn't have the funds to buy an Installer / Remover.
Out comes a sledge-hammer and a piece of pipe. Tap-tap-tap. So, I wonder if someone beat on these things?
Believe it or not, I used to "Heat Treat" thousands of those balancers (But not GMs) The part was soaked in oil in huge bins. Then (back-breaking) shoveled onto a steel conveyor belt. And that moved at a snails pace through a 70 ft oven at 1200 degrees F. About a four-hour job plus cool-down. They were cherry red coming out.
At any rate, an explosion like that is some scarry ****. A steel hood would have contained it, but with a glass hood, YIKES!
Last edited by HeadsU.P.; Jan 9, 2023 at 05:04 PM.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
After my first rebuild of my 327 I went with a new one. Folks here were talking about the balancer slipping and I was concerned about that, not so much it would come apart.....but I loved shifting around 7000 rpm as well... I like fluid damper balancers
Mine had cracks when I pulled it apart. Could happen to anyone. I only went looking when I couldn’t time it. It was way off. Hope you weren’t far from home.
Was under the motor recently and noticed some sort of powdery residue on the back side of the rebuilt original balancer. I pushed on the outer ring And it moved for and aft. Not good. So this is going on in the Spring. I’m not messing around anymore.
So if you want SFI approved safety, and an original look, and the convenience of etched timing marks:
Then you can paint yours the way I did: I taped off the one section.
Was under the motor recently and noticed some sort of powdery residue on the back side of the rebuilt original balancer. I pushed on the outer ring And it moved for and aft. Not good. So this is going on in the Spring. I’m not messing around anymore.
Be sure to plan some time to hone the balancer to fit the crank. ATI's are the best..but they typically come undersized because they have no idea what crank it will be installed on.
I wonder if the balancer was ever installed with a hammer causing the ring to bust a piece off? The inertia ring is flat broken, yet the rubber still looks all intact .
I had a Pressure plate explode on a 65 Mustang 289HP at 7200 rpm and it shattered the bell housing back in the early 80's. broke an ear off of the transmission , broke a bell housing mounting boss off the corner of the engine block , destroyed starter and everything inside the bell housing , split a cylinder wall too , it basically just ruined everything accept the rear differential , I had to live off of peanut butter sandwiches and tomato soup for a year to pay for all the parts I broke
Harmonic balancer came apart
