ATI just spun off my keyed balancer..help!!
 

Okay, here's what I have(or had) on my car:
D1SC 7.65 ATI LT1 balancer pulley
Keyed Professional products SFI Damper
Keyed crank hub/crank w/woodriff key installed.
3.4 pulley-making 11# boost on my car

Here's what happaned:
I dyno tuned my car and beat the crap out of it-no problems
Then, at the track, I blip the throttle to clean out the plugs and then my damn **** pulled right off-crank bolt, balancer, ATI spacer/crank pulley, belts etc.

I don't understand how this happened as my ARP crank bolt pulled out, threads were good, but it was bent.
My balancer was split at the spot where it is keyed all the way through.
The key was in good condition.
The spacer/ATI crank pulley was still in tact as one peice like it is installed.
The crank is not bent, threads are still good.

I think the keyway on the damper split under the pressure, then it was spun off the crank-backing out the bolt, and then bending the bolt as it came off. The bolt did not break.

Anybody with a LT1 and some moderate boost have some advice? I used loctite everywhere, yet this still happened. What should I do next time??? I just lost 1,000 in parts and dont want this to happen again. please help or offer your .02!!! Thanks!!
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cracked keyway slots are a common problem, you can get an ATI damper with a bigblock hub installed on there so there is more meat there and it dont crack, then you need a timing cover as well thats milled out with the bigger seal for it to fit in there. Lonnie could take car of you.

Can you direct me to Lonnie? Thx!

http://www.lonniesperformance.com/

I did this mod over the winter and it is kind of a pain in the butt because you have to remove and replace the timing cover but I'm glad I did it. Nothing like a 20lb frisbee coming off the front of your car. :) Do a search on "Big Block Hub" and you'll get a bunch of hits on this problem.

So the big block hub will keep this from happening again? I thought my SFI balancer w/keyed hub was good enough. I wonder if maybe something between my crank damper and ATI blower alignment is making even the slightest tweek to the front of the car and pulling on everything accordingly?

I lost my opti, alt bracket, hood, SFI balancer. ATI crank pulley, belt, etc. Do you think the BB hub will keep this from happening again? Thx a ton!

been there done that, got the bill to prove it.
i had to remove my crank
take it to the machine shop and they welded where the crank chipped and put double keys in it. i didnt have the burnout pin on when i did my burn out. 10k+ rpms let off and the blower wanted to continue spinning but the crank didnt.
i was f-in pissed too because that was the day Horsepower TV was at the track and that idiot with the blonde hair joe kept asking whats wrong with it.

another 406 n/a motor i was going through the wall, to the burnout box and the car shook like hell, if felt like i was in a earthquake. then it stopped, so i thought everyting was fine. pulled up and a guy came running around the car telling me to kill it. he had my balancer in his hand.
oops, saved the motor though.

406 Meth,inj. 871. not an lt1

Ya, the hub cracks at the keyway where the metal is the thinnest. The big block hub is not really for a big block chevy it is just thicker metal around the neck of the hub with a small block chevy inner diameter. This hub is approx a 1/2 inch thicker than the normal hubs requiring a bigger front seal in the timing cover. You can buy the cover from lonnie or you can buy the seal and have your cover machined. Also you must make sure you get the correct press fit .001 hub to crankshaft or you can break the crankshaft.:eek: The balancer has a true surface for the crank pulley spacer to sit on. Lonnie has the specs to machine a spacer for your Procharger Crank Pulley. This hub also has threads taps into it for the three procharger pulley bolts (or six if you choose) although they are bigger than the normal bolts and you have to go to hardware store for them. This setup will take alot of stress off the balancer and crankshaft because the balancer and pulley run truer to the crankshaft. He even has an aluminum 10 percent underdrive balancer that is actually cheaper than the normal balancer. The hub comes with a single keyway which I think is enough for all but the wildest configurations.:)

Chances are you had a misalignment or press fit problem with your old hub/balancer as this usually only breaks on high boost/high rpm cars.

I see, so you think I may have not had the damper fully installed tight enough to the crank? Thx for all your help!!!

What do you mean by the burn out pin?

97WS6Pilot,

Thanks,
Couldn't have said it better myself.

Didn't mean to steal your thunder but I was very pleased with the product.:)

I'll be ordering your setup soon! Thx for the advice and excellent support by phone!!