Harmonic balancer bolt question
 

From a practical standpoint, is it possible to strip the threads either in the crank snout or the retaining bolt? Would seem more likely to possibly cross thread. Thx for any replies.

Hmm, never had that happen. I'd be interested in the replies.

99% of the time, If you have a factory Crank Balancer Retention Bolt, it will be a snug fit with you screw it into the crank, BY HAND OR WITH A SLIGHT FORCE USING A BOX END WRENCH. And the length of the bolt/washer to the end of the bolt should be a smaller length vs the depth of the hole in the crank snout with the balancer installed. YOU DO NOT WANT THE BOLT BOTTOMED OUT IN THE HOLE.

If this is the case you can torque that bolt to the specified PONTIAC crank bolt torque spec. A used factory crank/bolt should never be an issue but a billet or machined FORGED crank should have that dimension checked.

Tom V.

There was a member (Socrates I think?) here many many years ago who had that happen in a car he bought - either cross threaded\damaged the threads and the bolt wouldn't come out. It was a saga and a half that he detailed how to get it out and plenty of folks chimed in about how they'd never seen it happen before. I do not know if he had to have the crank fixed or not.

So to answer your question, I am sure it is possible but is extremely unlikely per the many experienced folks around here (and my personal experience too).

100% this. And in my experience, you are going to break the bolt off before you strip the threads in the crank out, especially if it's a forged crank. A friend of mine warthogged the crank bolt in and it snapped off...

A fine thread bolt such as those are in my opinion are very hard to cross thread!

If the proper really thick washer was not used ( which I have seen! Then the bolt bottoms out and can be more then a Bear to break free!

Not sure what you have posted is valid, IF you are using the original bolt with the thick washer (without the balancer installed) THEN you should install a few thick steel washers on the bolt (before you install the bolt in the crank). THIS will keep the bolt from being wedged in the crank and possibly stripping out some threads.

The Crank Bolt was designed by Engineers to have some distance BEFORE the bolt bottoms in the drilled and tapped hole when the balancer is installed.

I use a factory "no balancer ring" hub to mount my large degree wheel and a similar set-up (minus the degree wheel) to just turn the engine over. You can remove the bolt by hand almost when you do it that way. The washers will work fine though too.

Cranking on the Harmonic Balancer Bolt (no balancer) is almost guaranteed to cause thread issues inside the crank over time.

Tom V.

I have seen the threads in stock Pontiac crankshafts strip out of the crank nose at the first 1/4"-1/2" of the threads. Two things generally cause this. 1. Using a balancer puller with a tapered nose that is too small for the large Pontiac size hole. The tapered nose goes too deep and snags-up the first couple threads in the crank nose. 2. Using the factory bolt to push the harmonic balancer back on during reassembly. If you don't get the balancer started at least 3/4" with a block of wood and a hammer, or better yet with a proper installation tool, the bolt will not engage enough threads and chew up the first several threads. My advice is to run a 5/8" fine thread bottoming tap into the crank nose to clean-up the threads, and then install the balancer properly and use a new bolt. Worst case situation, you can repair the crankshaft nose with a coil insert or a solid insert. It's very important not to bottom the bolt as mentioned and verify a minimum of 160 ft. lbs. with light oil on the threads and under the head between the washer,.

Thanks for all the replies. My known real problem is that my damper bolt is not tight enough. I had a "reputable???" shop recently replace my timing chain & gears. They apparently screwed up on this and a couple other issues. Concerning to me that I drove the car home (15-20 mi) with the bolt that way.
At my age & health condition I just can't crawl around on/under the car anymore wo getting pretty messed up. Getting close to getting out of the hobby I'm afraid.

Replaced my balancer last yr. with a Pioneer (factory style) with new bolt/washer, blue thread locker, pulley retaining ring. No issues. On yours, I suspect they used the wrong bolt? Too long?

A loose balancer bolt can taper the crank snout, but can't see how it would damage the threads.

There is a run-out value for the crank snout, and used to check that when buying used OE cranks. But it's been a while since I've used an OE crank.

Remove the bolt, inspect the threads, and chase the threads in the snout. That should remove any doubt of damage. If the threads look fine when you remove the bolt, you're probably OK.

As others have commented, make sure the correct thick washer is being used on the bolt. If there's any question, replace both the bolt and washer. The ARP replacement ones are fine, and I've used them exclusively for years.

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Just to add, IF the bolt was loose, it takes considerable miles to wobb-out the crank snout. I've seen it happen to folks who don't apply the correct amount of torque, and upon inspection after next removal, have noticed visible wear, but that's after 10s of 1000s of miles.


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I'm "assuming " they reused the original bolt and washer, although I don't know that for certain. I had a new bolt & washer that I got from our host eons ago, but they didn't use those. The originals have been in the car since I got it in 2001.

Think about it.
If you got the car and the originals never had any repairs (the exception being the cars
built in the mid 60s with the Nylon Timing Gears), your engines and the Bolt have probably been off the crank from no more than a couple of times, unless the engine was played with and either raced or rebuilt at one point in its life.

That being said the Original Harmonic Bolts should be like a NOS part and good to go for years to come. I never throw away a Harmonic Balancer bolt removed from a junk yard engine. They are as good as you can get for a Pontiac engine vs the Chinese stuff out there. I wish I had kept a few more over the years vs give them away.

Tom V.

Hmmmm....
 

Was his name Eric? :pound::pound::pound:

That boy could break an anvil! :D

If a shop isn't aware of the torque spec or don't have a torque wrench that reads high enough, they may resort to the "good-n-tight" method or just blast it on with an impact. Some mechanics also think it's the same a s a Chevy.
If you've ever owned a Honda, their harmonic damper attaches the same way as a Pontiac. Those are fun to get on and off off too but the special crank holder tool makes it easier.

Automotive Sears Beam Torque Wrench will not go there, a good Snap-On Torque Wrench will allow the 160 torque spec, as will most of the heavier TRUCK torque wrenches.

Tom V.

I assume that locking the flywheel is the best way to keep the engine from rotating while tightening the damper bolt? Any other methods that work well and are not too complicated?

If it's a manual trans car, put it in gear and set the parking brake.

Works every time. If I don't have the driveshaft or Brakes hooked up in the car I have a fabricated 4 foot piece of 1" heavy wall tubing with the Driveshaft Yoke bolt pattern on it and use that to lock the trans/engine so I can tighten the bolt. 3 foot cheater on a 1/2" breaker Bar gets me in the ballpark then the industrial torque wrench is used for the final torque on the bolt.

Tom V.