Question on 389, interchangable parts?

Just purchased a 66 Catalina, with a 389 2/barrel. I noticed that the crank pully's where wobbling a bit so went to take off the center bolt and noticed that the motor was turning even with the pullys held tight. Well to make a long story shorter the harmonic ballancer shaft that goes into the motor had cracked in 2. The only thing holding it together (thank god) was the thin sleeve they put around the shaft.
MY question is, what all balancers will fit this motor? Will a 400/455 balancer work on the 389 (code 92 on heads) I also notice that there isnt or I didnt see a pin that keeps the balancer and crank spinning together. Am i missing something here? Any help here would be greatly appreciated!

So you're saying the crank is broke?

If i'm not mistaken most Gm big block HB should be the same size and approx wieght.
The pully would need to be identical if the one you have isnt good.

My Grand Am SE(V6) had a SB chevy HB on it for some time and it was the same size.

And yes thier should have been a keyway locking the HB in place, to keep it from spinning on the crank.

Also the HB bolt torx to 160ft lbs if I'm not mistaken.
I have other specs at hand for this engine if you need anything else.

The 389 balancers are "assemblies". That is, there are two parts. There's "hub" that bolts directly to the crankshaft. There's a woodruff key that aligns it to "TDC", and the timing mark is scribed on the hub. Then, there's the "inertia ring". That's the outer piece (installs inside the pulleys), with 6 5/16-24 bolts holding it together.
The most common failure with this design is the inertia ring becoming "unbonded" (the rubber delapidates and the outer ring rotates or "flings" off.
If the hub is cracked, it's usually along the keyway. That isn't a normal failure. It usually takes a catestrophic engine event to stress it enough to crack it (or an improper installation). Unlike Chevy engines, the Pontiac has a "slip-fit", where there's actually about .002" clearance between the crank and the ID of the hub. It should come off easily with light tapping from a soft hammer. After a good cleaning of the snout, it should slide on with zero effort.

Pontiac V8s are in no way, similar to Chevy. There are no interchangeable balancers between the Injun and any other GM engine.

The 2-piece unit was used through '67, on all V8s. '68 brought the later 1-piece design, but the pulleys, water pump and timing cover are all different. For your '66, '64 through '67 should fit.

As a last resort, "Damper Dudes" in SoCal rebuilds them. If the hub's damaged, they may not be able to fix that. They "re-bond" the inertia ring, and their quality is excellent.

If you can't find a hub, e-mail me. I can find you one.

Jim

Yes I guess I have heard and seen the rubber rot on the inertia ring and the hub wobbles.
Very dangerous if it flys off :yikes:

I wasnt certain on what year(s) they stoped using that two piece design, thankx MrPbody !

srry, had to get a new screen name.
Ok I think its the hub. It broke where the key mark is inscribed. It is the part that goes inside the timing chain cover and goes around the crank. Im guessing it broke from haveing an A/C unit installed on it from the dealer back in 66. Plus my buddie racing it after we bought it on the way home. The reason i think it didnt shatter and completely get destroyed is because of the thin metal "micro sleeve, harmonic balancer repair kit" band that went around the outer part of the balancer, that slid into the timing chain cover. It kept if from just breaking off and falling off. Well I guess im going to put this sleeve back on when installin the new HB. Since it seems like a nice piece of insurence for $5. As far as the motor it runs very good, not ticking or anything, very strong.
I picked up a used HB for $25 its off a 64 389. Ill put it on as soon as I get it and let you know how it works out. I just hope there isnt any damage to the key area on the crank.