Judgebull

We all know the problems with LS3 harmonic balancer problems some Corvette owners have experienced. Has anyone with one of the hand built, dry dump engines suffered a harmonic balancer failure?...😎

RoadkingC6

I can't answer your question, but hand built engines or not it's not the build quality failing it's the part itself, so i don't see why it would make any difference in any harmonic balance failures other than the luck of the draw meaning which balancer your car gets because not all of them go bad.

enventr

Also on the LS2

Landru

Have followed Z06/LS7 entire 8 yr run, owned an '08 from 03/09 to present, and can honestly say I've yet to hear of a reported HB failure w/ LS7.
Highly doubt it but I could've missed 'em.

FWIW I've wondered the same question over the years since I've skin in the game. That and reading repeated LS2/3 HB headache stories.

No clue except guessing LS7's HB's somehow different from the other LS series.
What say you pro wrenches?

Seadawg

Subscribed. I have a dry sump LS3 with 80k and no issues, knock on wood. Never seen or heard of any dry dump HB issues either, let's see if this thread flushes out any.

RoadkingC6

The balancers for dry sump and non drysump, big block and small block Chevy's are all different part numbers, i'm sure they are all made by the same manufacturer, but it seems as though the balancers failing are only the LS2 and the LS3 balancers.

simplegto

The LS1 and LS2 in the GTO had no balancer problems.

puzzleboy

I changed mine on my C5. Not a huge deal, but the steering rack had to come out. Job takes a few hours.

Most of them wobble..... Do they actually fail? No idea.

Dutch08

On my son's C5, the outer part of the balance spun into the engine block. So it can be a big deal if it fails. If yours is wobbling I'd keep my eye on it.

not08crmanymore

That issue has been around for years and GM refused to warranty it for quite some time.There was,eventually, some kind of fix with a diamond bolt or whatever it is that get put in there that was supposed to correct the issue. I've owned 5 c6's from 1-05 - 2-08's-2-13 GS's...as well as a 14 and never had the issue myself.If you use the search function on top there,there is all kinds of info and you possibly may find out if anybody with the hand built had the issue.My 2 GS's were with the hand built and were fine as long as I owned them...

Judgebull

Does anyone have experience with the failure mechanism of these Harmonic Balancers. From what I can tell most of the failures relate to the outer pulley ring seperates from the rubber ring that binds it to the hub. Other failures relate to the Balancer hub that fits on the crankshaft, coming loose on the shaft. I think this would involve the large bolt holding the Balancer to the crank either backing out or failing and breaking. Any experience, descriptions of these failures would be appreciated, photos would be awesome. Thanks...

BlindSpot

Both failures are pretty well documented. HBs wobbling and coming apart, and bolts coming loose and spinning out of the crankshaft on early bolt pns.

Most of the failures involve the outer pulley first wobbling on the inner hub because the rubber center band fails. Many catch it in the wobble stage and replace, some ignore it and some of those completely separated causing the outer pulley to either spin off forward, or mostly spin off toward the motor usually destroying the timing cover. Some have actually been told a little wobble is OK...NOT! HBs should spin true especially on a high hp/torque motor.

On the bolt issue, I haven't heard of any snapping, but spinning loose and leaving the crankshaft is pretty well documented.

The HB is an interference fit on the crankshaft, no key. For an NA motor, this usually doesn't present much of an issue, but supercharged mods can cause the HB to slip/spin and possibly loosen the bolt. The recommendation on an FIed engine is to pin the HB to the crankshaft.

When I did my FI, I pinned both the bolt AND the HB, so in this configuration, neither the bolt nor the HB is at risk.

windyC6

Inquiring minds have to know.....whats you plans for getting that bolt out when/if the time arrives ???

extrapilot

I was going to ask the same question. Maybe he drilled the hole deeper than the pin, so if pushed in, the bolt will clear.

TBIRD57

i thought my 2007 was safe.!

LsLegacy

What are the symptoms? My car shakes when accelerating to 70/80 mph. It eventually goes away, but I've been wondering what's causing this.

BlindSpot

It's completely serviceable. You seem like a smart guy. Give it some thought, maybe you'll figure it out.

HBsurfer

Balancer went out on my 2007 at 25,000 miles
All C6's use the same poorly designed balancer

HBsurfer

Look down at your balancer from the passenger side of the engine bay with the car running. If it is wobbling, you have a potential problem.

unixcorn

I'm an idiot so if you care to share how you get that bolt out, I'm all ears. I don't see how you can turn the bolt without pulling the pin. I don't see how, without drilling or cutting, you can pull the pin out. The one plausible thought in a post above was that you drilled the pinhole deep enough in the crank to punch it in far enough so the bolt head would clear when it's time to remove it.