ATI Torsional Damper / Harmonic Balancer

[Jagdpanzer]

Was in Baltimore on business today and made the mistake of stopping by ATI Performance Products on the way home. What great bunch of guys. Told them I was in a hurry an just stopping by to pick up some info on their LT5 torsional damper. After providing a full product briefing they insisted I stick around for an extra 15 minutes while they assembled an LT5 unit for me check out. Anyway to make it short I couldn't leave there with out it after laying eyes on it. A fine piece engineering and machine work as you will ever see. Here are pics of the ATI and stock unit and the massaging I had to do to a couple of the water pump bolt bosses on my 402 stroker build in order to achieve adequate clearance as you can see the ATI is slightly larger in diameter in this area.

ATI Part # 917298 (may be discontinued)

http://i540.photobucket.com/albums/gg333/pwasinger/IMG_6637.jpg

http://i540.photobucket.com/albums/gg333/pwasinger/IMG_6638.jpg

http://i540.photobucket.com/albums/gg333/pwasinger/IMG_6634.jpg

[Polo-1]

1 pound lighter or .5 pound can't remember.. Just under $600 to my door.

Need to thank Todd P. for this, he paid all the up front money for ATI to make it a ready to buy part.

[secondchance]

Looks like you are well on your way to finishing. What is the target date for 402 completion?

[Jagdpanzer]

In the spring after the next Virginia emission test which I will do with the stock motor still installed.

Looks like you are well on your way to finishing. What is the target date for 402 completion?

[ZR1Vette]

Very nice! Look forward to seeing the built engine :cheers:

[HAWAIIZR-1]

Thanks a lot Phil!!! :cry: I am going to pretend I did not see this post. I am putting my "stock", balanced, torsional damper back on today as a matter of fact so no, I am not going to stop what I am doing to buy this ATI one and throw a curve ball into my build.

All kidding aside, it looks great and I can't wait to hear about your motor. I wish I had the funds and would have built that set up you have; sounds like the perfect all around motor.

[Jagdpanzer]

Thanks a lot Phil!!! :cry: I am going to pretend I did not see this post. I am putting my "stock", balanced, torsional damper back on today as a matter of fact so no, I am not going to stop what I am doing to buy this ATI one and throw a curve ball into my build.

All kidding aside, it looks great and I can't wait to hear about your motor. I wish I had the funds and would have built that set up you have; sounds like the perfect all around motor.

Craig,
Best advice I can give you is just stay away as far as you can from the west side of Baltimore, MD where ATI is located. I guarantee you will not be able to resist getting one of these otherwise.

[HAWAIIZR-1]

Craig,
Best advice I can give you is just stay away as far as you can from the west side of Baltimore, MD where ATI is located. I guarantee you will not be able to resist getting one of these otherwise.

Phil,

I know you are correct and it is a good thing I live so far away from ATI. If I did not have my motor balanced from damper to pressure plate I would probably consider it, but I can't handle any more delays and gotta bolt on those GVD heads today. Thanks for sharing; I'll keep it in mind when I get rich enough to build another "BIG" motor.

:cheers:

[Polo-1]

ATI part number is 917298

Here is the listing Jegs has for them:

http://www.jegs.com/i/ATI/085/917298/10002/-1


The price has dropped from way back when I bought.. At that price I would not even look for a stock part. I think Todd had about $1000 into set up cost.

[tpepmeie]

Yeah, that price is close to what I paid in just for the design fee :( Oh, well, that's what I get for ordering the thing back in 2007 before I had even really started building the rest of the motor.

P.S., I had to get the hub ground to size, as it is just too tight for most cranks.

[Dynomite]

ATI part number is 917298

Here is the listing Jegs has for them:
http://www.jegs.com/i/ATI/085/917298/10002/-1 (http://www.jegs.com/i/ATI/085/917298/10002/-1)



You need to trim the water pump bolt hole boss, and remove the front cover timing tab. Then the ATI will fit the front of the motor.

What I think Todd is having a problem with is , the ATI hub is too tight on the crank snout. The yellow or pink paper work said how much interference the fit is to be. I had to have my hub honed out for the Moldex crank.

I had to get the hub ground to size, as it is just too tight for most cranks.

So......The listing Jegs has for the Torsional Dampener http://www.jegs.com/i/ATI/085/917298/10002/-1 (http://www.jegs.com/i/ATI/085/917298/10002/-1)

Will require two water pump bolt hole bosses to be ground a bit, the front cover timing tab (91'Z) removed, and possibly the inside diameter of the Torsional Dampener Hub relieved :icon_scra

Or have these issues been resolved in the latest Jegs listing?

[Polo-1]

I know Jeff has used the ATI on a stock crank. The hub fits like it should. On aftermarket cranks the snout's are a couple of thousandths thicker than stock, so the ATI hub needs to be honed a couple of thousandths.

ATI is the same as the ATI from Jegs or who ever sells it.
Timing tab must be removed from any front cover that has a tab. 2 bolts and it off.
And the stock washer for the balancer needs to be trimmed down O.D.

[Dynomite]

I know Jeff has used the ATI on a stock crank. The hub fits like it should. Timing tab must be removed from any front cover that has a tab. 2 bolts and it off.
And the stock washer for the balancer needs to be trimmed down O.D.

:thumbsup:

There are degrees on the ATI Torsional Dampener. If I were to modify the timing tab (the ATI Torsional Dampener does not interfere with the timing tab bolts it appears) could I use that timing tab in conjunction with the degrees on the ATI Torsional Dampener?

Or are those degrees (TDC for example) on the ATI Torsional Dampener located at a completely different location than my TDC location on my existing (stock) Torsional Dampener with respect to the Torsional Dampener hub keys?

It appears if we keep the rpms under 5,500 we are in fine shape with a stock Torsional dampener :cheers:

Who does that :sign10:

[Polo-1]

:thumbsup:

Or are those degrees (TDC for example) on the ATI Torsional Damper located at a completely different location than my TDC location on my existing (stock) Torsional Damper with respect to the Torsional Damper hub keys?

not that far yet.. still has a 18" Moroso degree wheel hanging on the front of the crank... need a couple of weeks.

[todesengel]

Picked up two of these in the past couple months. Pete has one, and I have one for mine that I modified.

I think the cost was down to 405 bucks shipped from Jegs =D>

[Locobob]

Just ordered one of these for my car, need to get this thing back on the road!

A big thanks to Todd for his involvement in making this happen! I shall seek to return the favor someday. :cheers:

[tomtom72]

Apologies up front for asking these Q's.

I remember reading some threads about our OEM dampers slipping with age? Is this true? It seems logical to me as the rubber ages, right?
At what mileage should I start considering this as critical? I have 50k now.
Will these ATI dampers work on a stock motor with a stock crank? Or do you have machining to do?

TIA
:cheers:
Tom

[Polo-1]

Yes, you should be looking at the damper. These things are 20+ years old now.

The common way to see it, the out ring moves out of line from the inner ring. Looking at the "face of the damper" you should see the outer ring thin rubber line and the inner ring/hub. If these are not in a straight line, you might have moved. The ones I have seen are shifted to the front cover side. A second way to inspect is to put a white strip from hub out to serp belt. if the line ever gets shifted you know it's starting.

This is why I like the ATI. It bolted together, no shift/slip.

Now it looks like they are down in price ($400 +or - ) it's a no brainer.

[Polo-1]

You never feel it.

It would not pass the nickle test if your original damper had a lot of pins. Most only have 2-4 pins.

Who have put a aluminum flywheel on. dont forget the original had pins too.....

[tomtom72]

Thank you Kevin! :thumbsup:

I guess it's time to go to Jegs & order up one of them.

:o I guess my old sbc puller will work on an LT5 damper, with the motor in the car? Or am I calling Kent-More and buying a new tool?

:cheers:
Tom

Cliff, I'm not an engine guru but if our motors were balanced internally a damper is a damper. My 72 LT-1 was internally balanced & the dampers were balanced individually via drilling out metal on the outer ring. The only thing you could not do with those dampers is use a regular sbc damper on an LT-1. In our case the pins I would think have more to do with the transmission gear noise than balancing the rotating assembly.....that is just a thought from my pea brain.:o I'm going to go look in the FSM and see what there is to see. Right now I'm shooting from the keyboard....so to speak.:icon_stud

[Polo-1]

Yes, They are internal balanced. They were also ( I think) were hit with the strobe for the final balance. This is why the pins in both the flywheel and damper. This is how the made the nickle stand. If you remove the flywheel and damper, its not the end of the motor. It just wont be any better then all other factory built motors.

[tomtom72]

Thanks for the heads up on the r&r Cliff. I guess it's no picnic with the block in the car. I guess I'll have to figure out how to get the new one back on before I do this r&r.:thumbsup:
I guess I will try to examine my damper closely to determine if the inner & outer rings are no longer concentric. I just don't have any clue how to tell if the rings have slipped relative to each other.....but I guess that wouldn't matter much seeing as there ain't no distributor to set timing....I guess the only thing that would tell you is the rubber is shot.

Kevin, thank you for sharing the info. :saluting:

[Jagdpanzer]

On the Bryant 4.0" stroker crank I'm using for the 402 build project the motor machine shop doing the engine balancing had to hone out the hub some in order to get it to fit properly on the crankshaft snout. They said this is their usual experience with ATI dampers they've seen before.

[Jagdpanzer]

But...Kevin suggests that is only on aftermarket cranks :dontknow:


In my case I also have a spare OEM LT5 crankshaft to compare and it's snout diameter is identical to the Bryant I'm using. However, your mileage may vary.

[HAWAIIZR-1]

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC01919.jpg


I have only built 1 LT5 so I'm no expert, but I replaced my torsional damper just for peace of mind even though there was some minor cracking in the rubber with 52K miles. I replaced with stock OEM NOS one and had it balanced with my motor and here is how it looked after balancing.

In my case the the only change from stock was pistons and connecting rods from a 95 crate motor, but the stock flywheel was replaced with a fidanza aluminum so it was balanced with all the new components as an assembly from the damper to flywheel. I'm not sure how necessary it was, but I like the peace of mind knowing that I balanced the motor this way.

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC01921.jpg

When I build my next motor I'll go with the ATI.

[Polo-1]

Yes, the ATI will have to be honed for aftermarket cranks ( I know this for sure). Stock not 100% sure.

Fidanza flywheels are not a true 0 balance, I know this as mine had to be drilled to. Although mine was not as far out as Craig's.

The stock timing tab will fit back on the cover, with a little work.

http://i7.photobucket.com/albums/y292/kpie/IMG_2447.jpg
http://i7.photobucket.com/albums/y292/kpie/IMG_2446.jpg

[flyin ryan]

On the Bryant 4.0" stroker crank I'm using for the 402 build project the motor machine shop doing the engine balancing had to hone out the hub some in order to get it to fit properly on the crankshaft snout. Not un-common at all. Every combination is different (Stock - Aftermarket cranks), just have to measure at the time. Don't assume anything, just measure....Necessity is the mother of all invention but Assumption is the mother of ALL screw up's!

[todesengel]

My Ati required some work as well to fit on the stock crank. Ryan is completely correct on this point.

To be fair I would rather have to take a little material off for a lovely snug fit than have some sloppy tolerances on this piece.

[GOLDCYLON]

Kevin a brand New ATI is on its way to you. Thanks for the Sage advice ;)

[LGAFF]

I called ATI as the pulley seems like something that could be swamped out with an underdrive unit, appears that the pulley is very specific to the application and there are no other pulleys that they make that could be adapted as an UD unit.