LT1 Damper bolts?
 

Anybody know the size (or ARP part #) for the LT1 harmonic balancer and crank flange bolts?
It should be a total of 6 bolts (don't need the main bolt in the center with the washer that presses everything together).

I don't think ARP makes those, I checked their catalog and couldn't find any mention of them.

It's driving me off the wall. I went with a set of ATI's that summit said would fit; turns out rather the Pioneer damper and crank flange are a different thread than OEM or summit was wrong. I emailed Pioneer and they said the stock hardware works so summit must have been wrong yet again.

I may have a brand new one from GM. I ended up purchasing a stud kit from ARP because the threads in my Callies DS start way deeper than the stocker. You want it for a few bucks if I have it?

It's a unique length IIRC and sometimes people buy one thats "close enough" and it bottoms out on the crank before being fully tight....resulting usually in stripped threads in the crank.

Yes sir. That's the six? bolts and not the center one, correct? I could have sworn stock damper was 3 bolts and 1 center... but the Pioneer is six I believe.

Ahh I'm talking about the center one. The other six....nope don't have them. I use a ATI superdamper.

Ah I got an ARP center bolt... summit better not be wrong about that one too or I'd be pretty upset. That sucker was almost $30.

They are. Or were last summer. Consider your bubble popped.

What 6 bolts? I remember 3?

I remember 3 as well but the pioneer balancer and hub have six holes; 3 are threaded on the hub and the other 3 are threaded on the balancer; but that dowel will not let them line up in that order. I got no f-ing idea :kneeslap:

Got a pic or link to your damper? Sounds like 3 of those holes are for an old school pulley?

That would make sense but Pioneer designed these for the LT1 cars.

It doesn't matter anyway, I finally pressed it together to get a look at it and I have to show off their amazing machine work!

Now I get the wonderful joy of having to deal with these f'ing morons on the phone tomorrow:
http://desmond.imageshack.us/Himg705...jpg&res=medium
http://desmond.imageshack.us/Himg109...jpg&res=medium
http://desmond.imageshack.us/Himg600...jpg&res=medium


Check out how well everything lines up!
http://desmond.imageshack.us/Himg31/...jpg&res=medium

Doesn't mean the engine has to stay in a modern car. Sometimes they make generic stuff so they only have to make it once. But I get your point.

Are you sure you aren't supposed to use just 3 small holes? My ati damper will only line up 1 way too, maybe that is the case here? Tough to tell in the pics.

I'm positive. The 3 holes that aren't lining up properly are supposed to accept OEM bolts (7/16"-14 x .88"). The thread is the right pattern but the holes are about 1/8" off. The 3 smaller holes are tiny as can be and defiantly aren't right.
I don't see how it would matter anyway, the crank flange has an alignment dowel so it's got nothing to do with me not lining it up properly.
I've contacted Pioneer and CNC Motorsports. Pretty annoyed but I'm glad I checked before I sent it off to the machine shop.


It makes me wonder... if they can't even machine the bolt holes properly, should I really be trusting this balancer/hub flange behind a 7,000 RPM nitrous motor?!

I'd go with an ati piece rather than save a buck.

I was looking at ATI. It looked like the crank hub was built into it as one piece which turned me off.

I also wanna add that those 3 other threaded holes in the balancer may be for a old school pulley like WBT said, or even an add-on supercharged drive pulley or such.

I'm going to say that the hub is the issue, with the alignment dowel being off. The alignment hole looks to be centered on the balancer under one of the holes.

and i know it may be stupid, but have you tried flipping the balancer to the other side? lol

Good call with your bolt suggestions... defiantly didn't think about that but it makes sense.
And no, I have not flipped it over. It crossed my mind but that would throw the pulley alignment off.

i know my 96 LT1 out of an Impala SS has a different mounting depth of the hub compared to F body cars. so perhaps they have different hubs available and sent the wrong one? Im just trying to think of anything, no matter how silly it may sound.

I know it doesn't seem correct but the timing marks are facing outward (from what I recall on all the older SBCs the timing marks were on the inner side of the balancer closer to the timing cover). But that puts the thicker part of the pulley outward how it sits on stock LT1 motors.
Unless the backspacing of the pulley is different?!

And the flange is correct, I verified the part number. I guess I'll have to measure the backspacing on the stock balancer and the new one though.

well i bought a March performance "outward mount" pulley kit for my LT1. when i bolted it all up, the pulley was almost an inch off in alignment to the belt with everything else. i called March and thats who told me about the B body hubs being different and that the could machine the pulley they sent if i provided exact measurements for them. I never did anything about it.

Also about those other 3 holes, here are 2 LS1 pulleys which are just held on by the center bolt. They both have 3 threaded holes in them as well.

edit: those 3 holes are also used for removal from the crank. The puller bolts thread into them.

http://i32.photobucket.com/albums/d5...lancernew2.jpg
http://i32.photobucket.com/albums/d5...luidamprSS.jpg

Alright thanks for the information. That's gotta be what the holes are for.

I'll try flipping it around tomorrow. If pioneer or CNC motorsports won't exchange it, can I just remove the alignment dowel? I imagine it's not necessary anyway?

the only thing that alignment dowel would effect would be the timing marks. If you removed it, Once you have it all together, all you would need to do would be to confirm when the motor is at TDC compression stroke, and then re-mark the balancer to whatever type of timing tab you will be using.