ATI superdamper big block hub vs regular

well i got my unit today from ati...

Very VERY VERY SUPER VERY nice.. i feel SO MUCH safer... i have double keyed my crank and this thing came double keyed already...

it CAN'T BE clearer than this

I no longer have the pic :(

I feel so much better that is not going to break my snout!!!!

Yes, it does appear to be quite robust! :)

Just a reminder, you really want to put some clear coat or something on this so it doesn't rust. 3 weeks got surface rust on mine.

I got you from last one.. and i will ;)

Can you purchase the damper with the big block hub, or do you you have to buy it with the small block hub, and then buy the bb one?

You can buy it with the bb hub right from ATI.

--Sean

You can buy it with the bb hub right from ATI.

--Sean

Well in my case... they sent me the bb hub AND sb hub... total with 2nd day shipping was 571

At what level should this be done to the car,

When should you get the key(one)
When should you go to 2 keys,
what do's it cost to cut the crank.

cost of crank i don't know as when i did it was with the build up so its included...

one key for ANY supercharger...
2 keys AND BB hub for T-trim or bigger i would say if you want to really play it safe... i don't think the T-trim is a NECESSITY.. but the YS is.

Well, I hate to install more doubt into the minds of fellow gearheads but the following has been my personal experience in this area.

I used to have a Fluidampr. It cracked along the keyway and in the process of failing, it chewed up my crank keyway. I had to replace the stock crank. I did so with a 4340 forging and replaced the balancer with the ATI Super Damper with BB hub. I then broke the snout off the new crank! The way I see this, the BB hub is so strong that it makes the snout itself the weak link. I even considered drastic measures:

http://www.rcdengineering.com/

The cost of this "solution" was rather high so I decided against it. I've since gone the twin turbo route because I'm tired of this, not to mention how much thinner my wallet is.....

Willie, did you bust it with serpentine belts or with cog belts?

Jim,

The initial failure with the Fluidampr was with a 12-rib serpentine. I used to see lots of belt dust so the belt was on extremely tight. On a third gen, ATI does not supply a tensioner -- we're on our own when it comes to tighening the belt. The second failure occurred after less than 1,000 miles on a relatively loose cog belt.

Willie

Wow, I must say I'm honestly surprised. I have heard that the cog systems were much easier on the crank because they do not require as much belt tension. There are lots of guys out there both on GM and Ford platforms using large blowers and running lots of boost, and I can't imagine that this problem has not been solved yet as I see many people doing this without a problem, or at least not a large enough problem to make them ditch the setup. What kind of crank were you using? Have investigated any other possible reasons why the second setup did not work?

On another note, has anyone investigated pinning the crank to prevent the hub from spinning and to spread the load out over a larger area? It's my understanding this is how the LS1 cars are.

Wow, I must say I'm honestly surprised. I have heard that the cog systems were much easier on the crank because they do not require as much belt tension. There are lots of guys out there both on GM and Ford platforms using large blowers and running lots of boost, and I can't imagine that this problem has not been solved yet as I see many people doing this without a problem, or at least not a large enough problem to make them ditch the setup. What kind of crank were you using? Have investigated any other possible reasons why the second setup did not work?

I've always heard that cogs are worse for the crank on LT1 cars because of the position of the blower... You tend to put more pressure on the crank with the cog because it doesn't give any, it continues to turn and never slip..

--Sean

Wow, I must say I'm honestly surprised.

I cannot describe the disbelief I went through when this happened in April. I felt my engine was bulletproofed yet the snout sheared right off.


I have heard that the cog systems were much easier on the crank because they do not require as much belt tension.

Exactly. And because my engine was just rebuilt, I was running my belt rather loosely.... I had no intentions of goosing it until the engine was broken in.

....at least not a large enough problem to make them ditch the setup.

I agree. However, I have just a minute amount of doubt that it will happen again. That's because we examined the engine in very close detail when it was disassembled, searching for any reason why this happened. We found nothing. So a couple of months ago, while my "new" engine was being built (again), I was apprehensive about going back to the F1, or any blower. I'm not made of $$$ and one premature failure like this is all I can swallow. So instead of spending more bucks for another possible failure, I decided to spend the same bucks to convert to twin turbos.


What kind of crank were you using? Have investigated any other possible reasons why the second setup did not work?

I knew you would eventually ask. This is a very long story. In a nutshell, we believe the crank was defective. I am filing a class action lawsuit against the manufacturer but more on this after it becomes official. Once it's in the books, I will post information about this manufacturer on every car related website I know of.... Stay tuned for this. If you want to know who it is, please e-mail me as I will not devulge this information on the internet until it's official. I will say one thing: This lawsuit is gonna be huge!

Willie

Yeah, I completely understand your point of view. If I had two failures with the same problem I'm 99% sure I would jump ship on the blower thing as well. Giving things a second try is one thing, giving them an 8th is another. :) If my setup wasn't already designed around a supercharger long ago, I'd be going the turbo route as well.

PM on its way...

do you have to do any mod's to the timing cover to get the bb hub to fit or is this a bolt on

do you have to do any mod's to the timing cover to get the bb hub to fit or is this a bolt on
Yea, the timing cover has to be bored out to the BB chevy size..

--Sean

After you bore out the timing cover(what is the cost) where or what gasket do you use..

Would the reg ati hub be ok (2 keys) with D1 or T-trim...

After you bore out the timing cover(what is the cost) where or what gasket do you use..

Would the reg ati hub be ok (2 keys) with D1 or T-trim...

For the gasket.. call ati.. they have it...

After you bore out the timing cover(what is the cost) where or what gasket do you use..

Would the reg ati hub be ok (2 keys) with D1 or T-trim...

I sent mine to ATI, I think it was like $50.. They have the gasket, but it's just a standard bb chevy front seal..

Some claim the standard ATI hub is too small and will break/crack...

--Sean

At what level would the stock hub (keyed) work

450rwhp-?
500rwhp-?
550rwhp-?
600rwhp-?
anything over 600rwhp you should go BB hub ?

The HP has less to do with the hub strength than the boost level. Above 15# I would recommend the bigger hub. If you run Cogs.... use the big hub at any boost level.

The seal is not a standard big block part.... it has a much smaller O.D. than a regular BBC seal. I have both & they are very different.

Yes ... boost level means how much strength or resistance the impeller will make...

when going to a ys-trim... where the impller is much bigger and boost levels are higher... air flowing is a lot more.. well... a lot of stress is put on the crank snout and hub... the ati hub tends to break exactly on the keyed portion.

Well.. the big bluck is so meatier that it gives me a bit more peace of mind.

The seal is not a standard big block part.... it has a much smaller O.D. than a regular BBC seal. I have both & they are very different.

Interesting, I was just going on what the ATI techs told me..

--Sean

The HP has less to do with the hub strength than the boost level. Above 15# I would recommend the bigger hub. If you run Cogs.... use the big hub at any boost level.

The seal is not a standard big block part.... it has a much smaller O.D. than a regular BBC seal. I have both & they are very different.


So anything under 15ibs of boost the stock set up with a key is good, then anything over that BB hub

Well......
This is sort of like the statement that your engine should be safe to 6200rpm.
Most will be fine & some have broken at 6000.

With 8# a stock keyed unit should be safe.
Personally if you are buying a new balancer, get the good one unless you are running an 8 rib, relatively stock combination with 10-12# boost in a daily driver, then the standard ATI should be fine. If you have the slightest vision of going 10's, don't skimp on parts.

Unfortunately there has been no scientific research done on this. If you use the cheap stuff, you may be the source of the research data. Personally Murphys Law gets me anytime I skimp on things, so I tend to overbuild to prevent doing things twice.

I have 1 car running 18# on the standard ATI. I have recommended to the owner to change it now that better parts are available..... If it splits, it may do little damage, or possibly ruin the crank & timing cover as well. If it breaks & comes off the engine, it will likely break the radiator, fans, waterpump, supercharger pulleys, tensioner & the optispark.

I have seen 12# kits (making 10# on a mild build) break a stock keyed balancer hub, ruining the above mentioned parts.

I also just finished a P600B '94 Vette engine with the standard ATI Balancer as it will only be 10# boost with the factory serpentine belt. Larger belts spaced forward amplify the stress on the hub.

Are you willing to risk possibly a few thousand in damage & your personal safety (or others) to save a few hundred? A loose balancer spinning at 6000 is a 10# frisbee. A few years back, just 3 miles from my house, a balancer came off a Chevelle at highway speeds. It hit the road, bounced up & went through the windshield of an oncoming car, killing the driver. How would you feel if this was your car or your mom in the other lane........ just to put things in perspective.

Here are pix of what happens if your scrimp:

http://para.noid.org/~lj/Hub1.jpg
http://para.noid.org/~lj/Hub2.jpg

I now have the bb hub plus machined front cover from Lonnie (thx!). I wonder what I'll break next? :D

:eek: :eek: :eek: :eek: :eek: How did yo do that :eek:

:eek: :eek: :eek: :eek: :eek: How did yo do that :eek:ys-trim + cog drive + single key hub = Boom #10.

Boom #10...... I like how you keep score.

I have my own personal toy box with broken rods, valves, springs, gears & too many others to mention. It is interesting to see how many things I have broken over the past 20 years. If I had all that money back, my house would be paid for......

Too bad we all can't be product test engineers that get paid to try to break things instead of footing the bill for our own testing.

Would there be a down side to ordering my crank with a big block crank snout? Would a(regular) big block hub fit?

What about the crank sproket for the timing gear? Anyone know if they make one that fits BB chevy snout and the LT1?

--Sean

What about the crank sproket for the timing gear? Anyone know if they make one that fits BB chevy snout and the LT1?

--SeanSeems to me the easiest solution is the hub with a big block OD and a small block ID. Even the thin seal is a NAPA part, and so is easy to get (p/n 22306). Get the hub and modified cover from Lonnie, a spare seal to replace the one you'll booger up, and you're good to go :D

What is the cost of the ATI sb hub where do you get the key.
what is the cost of the AtI bb hub where do you get the keys.

Seems to me the easiest solution is the hub with a big block OD and a small block ID. Even the thin seal is a NAPA part, and so is easy to get (p/n 22306). Get the hub and modified cover from Lonnie, a spare seal to replace the one you'll booger up, and you're good to go :D

Yeah, but for the guys that want to eventulally run really big #'s, the BB snout on the crank would be even better. Does ATI make a hub with the BB ID and OD? Then does anybody make a timing gear to go along with?

I am looking at going this route, but don't want to end up like Willie.

Anybody know?

Yeah, but for the guys that want to eventulally run really big #'s, the BB snout on the crank would be even better. Does ATI make a hub with the BB ID and OD? Then does anybody make a timing gear to go along with?

I am looking at going this route, but don't want to end up like Willie.

Anybody know?

What exactly do you want???

ATi does the big block OD with SB ID.

What exactly do you want???

ATi does the big block OD with SB ID.


I want to run a BBC snout- not just a hub that has a BBC od and SBC id. All BBC.

That way you don't have to worry about snapping the snout off the crank like what Willie did. The hub that you have will keep the hub from breaking, but maybe not the crank snout.

I wouldn't worry to much about snapping off a crank snout. That crank had to be deffective. I think Willie feels the same way, hence the class action lawsuit.

Anyhow, I just spun my factory hub/balancer assembly off the crank last night for the second time. :mad:

Even with all the Loc-Tite I could get on the dang bolt, it still backed out. I bought a new factory hub today at a Chevy dealer for $67 with tax included.
I'm gonna drop it off at the machine shop tomorrow, and have a keyway machined into it. I have an Eagle crank, that allready has the keyway cut into the snout, so it's ready to go.

I hope this doesn't break. Pray for me guys.

I wouldn't worry to much about snapping off a crank snout. That crank had to be deffective. I think Willie feels the same way, hence the class action lawsuit.

Anyhow, I just spun my factory hub/balancer assembly off the crank last night for the second time. :mad:

Even with all the Loc-Tite I could get on the dang bolt, it still backed out. I bought a new factory hub today at a Chevy dealer for $67 with tax included.
I'm gonna drop it off at the machine shop tomorrow, and have a keyway machined into it. I have an Eagle crank, that allready has the keyway cut into the snout, so it's ready to go.

I hope this doesn't break. Pray for me guys.

I snapped an Eagle Crank snout right off once already..

--Sean

Make sure the machine shop does not bore out the end of the hub so they can broach the keyway all the way through...... it will weaken the hub & may cause it to fail.

To machine it correctly, the key needs to be bored to the blind end of the bore.... EDM works well here.

I snapped an Eagle Crank snout right off once already..

--Sean

DAMN!!! :shock: Are you serious?! Which crank were you using Sean?

Make sure the machine shop does not bore out the end of the hub so they can broach the keyway all the way through...... it will weaken the hub & may cause it to fail.

To machine it correctly, the key needs to be bored to the blind end of the bore.... EDM works well here.


Thanks Lonnie! :thumb:

DAMN!!! :shock: Are you serious?! Which crank were you using Sean?

I don't know the part # off the top of my head, but it was a 4340 forged one.. I blame it on the tensioner from Procharger..

--Sean

I snapped an Eagle Crank snout right off once already..

--Sean

Exactly my point.....it's not as uncommon as one might think. That's why I asked the question I asked!!
;)

Anyone tried a one of the bearing braces that attaches between your pulleys like Pro Stock John is running? Bob Kurgan who made his claims this takes most of the stress off of the crank.

I think we need to get a GP going on this BB hub and front timing cover and the bearing brace, these things would sell like hot cakes......

i would like to no more about this brace as well

I am interested in this deal too, as I am in the process of looking to buy a Hub/dampner assembly.....

I think we need to get a GP going on this BB hub and front timing cover and the bearing brace, these things would sell like hot cakes......

i would like to no more about this brace as wellSince we're talking about GPs, is there any interest in a DynoJet Wideband Commander GP? I'm thinking about adding that product to Acceleronics. I talked with them at SEMA about this, and based on what they said, the price would be in the $450 neighborhood.

Since we're talking about GPs, is there any interest in a DynoJet Wideband Commander GP? I'm thinking about adding that product to Acceleronics. I talked with them at SEMA about this, and based on what they said, the price would be in the $450 neighborhood.

For that price I would be interested.

Ok boys I gotta chime in here. I have the same problem, I just got done snapping the crank snout off my Callies Racemaster crank just behind the timing gear. bent every valve in my AFR heads as well...
I was cog driving a F1-R, just stepped up from 19# to about 24#. Never did see it, just into 2nd gear at the track it went lights out.
So I'm getting ready to order another Racemaster, this time with a double keyed BB snout, sending my ATI hub back to get a BB one and they said they have the LT1 cover and seal for this set-up.
My two problems are the crank gear for the timing chain and the crank trigger ring.
I was running the LT4 extream duty chain. if I could just find the lower gear with a BB openning that would be great.
The other option I guess since I run a Meziere is to go to a old style double roller that can still run the opti, but it has to fit the BB snout. Any Ideas?
Than I have to figure out what to do about the crank trigger ring to.
Anybody do this yet I could use some help if you know...

Ok boys I gotta chime in here. I have the same problem, I just got done snapping the crank snout off my Callies Racemaster crank just behind the timing gear. bent every valve in my AFR heads as well...
I was cog driving a F1-R, just stepped up from 19# to about 24#. Never did see it, just into 2nd gear at the track it went lights out.
So I'm getting ready to order another Racemaster, this time with a double keyed BB snout, sending my ATI hub back to get a BB one and they said they have the LT1 cover and seal for this set-up.
My two problems are the crank gear for the timing chain and the crank trigger ring.
I was running the LT4 extream duty chain. if I could just find the lower gear with a BB openning that would be great.
The other option I guess since I run a Meziere is to go to a old style double roller that can still run the opti, but it has to fit the BB snout. Any Ideas?
Than I have to figure out what to do about the crank trigger ring to.
Anybody do this yet I could use some help if you know...

I was planning on doing the exact same thing, but I'm not ready to do it, so I haven't looked into it any further. Maybe if you call Cloyes or a timing chain manufacturer and see if they have something like that or make one for us.

I guess no ones gone this route yet?

If you look on page 3, there was some discussion on this, but pretty much scrapped because of the BB chevy hub/sb chevy snout piece from ATI.

Good luck!

--Sean

Thats why I brought up my problem to get it back on topic, going with the larger hub dose not solve the problem like a BB snout and hub would.
What I think I'm gonna do is take my LT4 ED timing chain crank gear and get it machined to fit the larger snout than broached for double keys.
Since I converted back to OBD1 and went to a FAST system I don't think I need the crank trigger ring any more, (Is that true? ) If thats true I won't worry about reinstalling it.
Anybody know the dia of a BB snout?

Ouch Phil. Sorry to hear that. With all the issues I know you've been through, it makes me wonder why I've switched to blower car now. Hmmmmm...

Sorry I can't shed some light on your question though.

Later,
Bob





Ok boys I gotta chime in here. I have the same problem, I just got done snapping the crank snout off my Callies Racemaster crank just behind the timing gear. bent every valve in my AFR heads as well...
I was cog driving a F1-R, just stepped up from 19# to about 24#. Never did see it, just into 2nd gear at the track it went lights out.
So I'm getting ready to order another Racemaster, this time with a double keyed BB snout, sending my ATI hub back to get a BB one and they said they have the LT1 cover and seal for this set-up.
My two problems are the crank gear for the timing chain and the crank trigger ring.
I was running the LT4 extream duty chain. if I could just find the lower gear with a BB openning that would be great.
The other option I guess since I run a Meziere is to go to a old style double roller that can still run the opti, but it has to fit the BB snout. Any Ideas?
Than I have to figure out what to do about the crank trigger ring to.
Anybody do this yet I could use some help if you know...

Thats why I brought up my problem to get it back on topic, going with the larger hub dose not solve the problem like a BB snout and hub would.
What I think I'm gonna do is take my LT4 ED timing chain crank gear and get it machined to fit the larger snout than broached for double keys.
Since I converted back to OBD1 and went to a FAST system I don't think I need the crank trigger ring any more, (Is that true? ) If thats true I won't worry about reinstalling it.
Anybody know the dia of a BB snout?


That's what I kept trying to say, but everybody seems to think that the hub is the answer, but it's not.

Since you are running FAST, I don't think you need the trigger ring anymore, but I'm not for sure.

Just taking a set of calipers to a BBC balancer here in the shop, I get a ID of 1.596. Don't know how accurate that is, but it's close.

In most cases.. the hub is what breaks.. ask lj...

in other cases the crank fails and the crank is the culprit.

In most cases.. the hub is what breaks.. ask lj...

in other cases the crank fails and the crank is the culprit.

My hub broke 2 times so far and took otu the crank AFTER the hub broke.. We found scoring marks in hub and crank snout that prove this.

--Sean

I was under the impression that part of the reason the cranks would break is because the hub cracked in the keyway, jumped the key, rotated on the crank, then hanging up on the key again once rotated the 360*, and that impact damaged the crank. Is this anything like what happens? If it is, I would think this new hub would greatly reduce the problem. However, if I were building a motor from scratch, I personally would at least investigate the BBC snout and see if it requires too much custom stuff.

Hey Bob, good to hear from yeah!
I heard rumors about you and the car.
Shoot me your # so I can call you and catch up.
It sucks about my car, But whatcha you gonna do. Just put it back together stronger and go hunting for the next weak point. Thats racing...

What is the part number for the ATI BB hub 10% underdrive, and what belt#

With the timing cover how much to you have to machine the hole bigger..

The dampner is the same as the stock LT1 they offer just the hub is different meaning larger.
I didn't ask if they offer a underdrive dampner.
They said they have the timing cover and seal as well.
I just mailed back my hub to be exchanged for the BB one. there supposed to call me when they get it to discuss how much all of it will be, I think they want to make sure the hub I'm sending them had not been installed yet before the tell me a price...

I guess no ones gone this route yet?
The oval track boys would know. Some classes REQUIRE this for safety.

I snapped an Eagle Crank snout right off once already..

--Sean
I feel your pain bro. Been there done that. 383 D1. 400miles on the motor belt was too tight snaped the Eagle 4340 crank right off. NOw i got less tension :D and a scat crank. What a pile of **** is an eagle crank it looks so cheesy scat unit is much better quality in my opinion

Does anyone have the part # for this larger diameter hub, and the seal that is needed for it? The pole smokers at ATI won't give me the part # for the seal :mad: . They're telling me that I have to buy a cover from them with the seal installed for $225.

Raymond

I don't know the part # for the hub, but the seal number is 22306 from napa.

Hub part # was on their website last I checked. :)

I don't know the part # for the hub, but the seal number is 22306 from napa.

THANKS!! :D I really needed the seal part #. I beleive the hub part # is ATI-916169. I think this hub has a 2.25" outer diameter, but I'm not sure. I'm just trying to get all the facts straight before I order.

Does anyone know the clearance from the hub to the snout for the damper? I read elsewhere that the hub might need to be honed to spec to fit aftermarket cranks.. thanks

Do a search for my name on here...I went thru the same thing about 4 years ago. It isn't the crank or the hub that is most likely causing your problems. The problem more than likely is the fact that most after market cranks have a more heavy radiused fillets and the timing gear is not machined for that. So then when you press the gear onto the crank it leaves a stress risor there because it cut into the crank when you put it on....combine that with the force of a blower belt on it....and it leads to trouble pretty quickly. The big hubs are great if you are going to be running a big blower...like a F2 or something of that nature and really cranking out the boost on it...but for most it isn't needed.

As for doing cogs...I've been back and forth on that and it leads me to believe that if your going to be doing street driving or in my case road racing you need to have some slip built into the belt for constant upshifting and downshifting because the blower can't keep up as fast as the motor. But thats just me.

Now it should be noted that I haven't had much time to work on my car since Oct of '03 working with 2 different race teams during the past couple years so I am in the process now of finishing the car so if anything bad does happen during the process I'll let you know. I did however put about 700 miles on the car before it was stored which makes about 7x more miles than what I made it before the first crank broke on me.

Anyway...back to the garage..hopefully she'll hit that 700rwhp mark after its all said, done, and tuned this summer.

Well that was what callies told me.. and i never checked that.... that is something that should come in the crank as a special note.. i just put it in carefully but i didn't do any grinding... i guess the crank is all installed and there is no turning back on that... i am anyways not going to dismount anything i have done here... i shouldn't have a problem but i sure hope to have good luck on it .. KNOCK ON WOOD

The reason they do not include it is the same reason they do not tell you how to put it in the block. Just one of those things that an experianced builder should know to do. I didn't ....hence had to learn the hard way....most of their customers however are more towards the pro. race teams which hardly ever have a problem.

Like I said...I haven't had a problem since. With most any streetable motor you shouldn't have a problem with such a small blower like a P or D series ATI or similar...only when you get into the really big stuff should you have to worry about it.

Now the guys running really big roots and screw blowers have an entire external front crank support to keep everything in line for them but again...apples to oranges.

I do have a strut bar for my supercharger that chris zorka made for me... along with bob kurgan...

I dont want that thing to break... i sure hope i didn't do any stresses.. i should be fine.. i mean i had it with my eagle and my engine builder that did a keyway (incorrectly btw) simply told me the crank is super tough.

I'm going to be running a 383 with a D1 and was wondering if the dual keyed BB hub is a must? I did some research and f
from lonnie's site http://www.lonniesperformance.com/lt1.htm the dual keyed set up breaks down like this

1) 2.25" OD LT1 balancer hub SBC internal dia.for ATI balancer - $119 - Is this the BB hub?
2) 2.25" OD LT1 ATI balancer shell 7.53" Stock Dia. Steel - $316
3) Modified Timing Cover for Above Hubs/Balancers - $186

Total amount for this set up is $621!! :eek: Anyone know if I can have the stock timing cover modifed instead of buying the modified ATI cover? And is this set up overkill for my app? I plan on running about 15lbs of boost.

-B

its not overkill.. i did modify my own cover... i got the seal from ati as well...

Yea, the timing cover has to be bored out to the BB chevy size..

--Sean
If this is on a '92-'94 LT1, I would suggest going with the '95 and up style opti-spark (make sure to use the correct dowel pin on the cam). Then you'll have to use the '96-'97 style timing chain cover. When doing this modification, you'll have to cap off the crank position sensor provision for '92-'95 LT1 motors.

Then you'll have to use the '96-'97 style timing chain cover. When doing this modification, you'll have to cap off the crank position sensor provision for '92-'95 LT1 motors.

Really? Thats the first I've heard of that. Whats the reason you have to use a 96-97 style cover?

Really? Thats the first I've heard of that. Whats the reason you have to use a 96-97 style cover?

The '96-'97 style timing chain cover is a different casting. It's a true surface to enlarge. The '95 timing chain cover is not completely straight and will not allow the crank seal to giver a proper seal. The '95 style timing chain cover is fine for the stock seal, but if the opening were to be enlarged, the larger crank seal will not sit in there properly.

The modification will work on a '95 cover as well. There is not a lot of material on these but I've done a few of them & they work fine.

The modification will work on a '95 cover as well. There is not a lot of material on these but I've done a few of them & they work fine.


I wouldn't suggest that. The '96-'97 cover is a better way to go.

I would just like to think everyone for scaring the piss out of me. I'm running the stock 9lb pully on my vortech with supplied hub. Now it looks like if I will have to upgrade if I increase boost or larger blower.

double post

Can anyone elaborate on Prostock John's setup?

Can anyone elaborate on Prostock John's setup?
He has a LS1 Firebird. He has a Strut brace running from his crankshaft to his blower -Vortech Ysi. Chris Sikorka sold him the brace. You can find pictures (maybe even buy his brace) over at www.LS1tech.com. He recently converted to turbo.

I'm going this route now with the BB hub, but the keyway(s) on my crank have yet to be determined as far as key size.

Does the keyway in the BB hub from ATI come pre-machined, or can you order it with the number and size keyways you want?

The BB hub from ATI is premachined with 3/16ths keyways cut into it exactly 180 degrees from each other. However I'm pretty sure you can order it with a bigger keyway machined in if you wish. However I wouldn't go with anything bigger than the 3/16ths since it'll remove more material off of the crank snout and possibly weaken it.

-B

I take it you went the BB hub route then?

Is the info you asked in this post correct then? I'll use it for my shopping list. :D

I'm going to be running a 383 with a D1 and was wondering if the dual keyed BB hub is a must? I did some research and f
from lonnie's site http://www.lonniesperformance.com/lt1.htm the dual keyed set up breaks down like this

1) 2.25" OD LT1 balancer hub SBC internal dia.for ATI balancer - $119 - Is this the BB hub?
2) 2.25" OD LT1 ATI balancer shell 7.53" Stock Dia. Steel - $316
3) Modified Timing Cover for Above Hubs/Balancers - $186

Total amount for this set up is $621!! :eek: Anyone know if I can have the stock timing cover modifed instead of buying the modified ATI cover? And is this set up overkill for my app? I plan on running about 15lbs of boost.

-B

Well, I put a call in to ATI to get the part numbers and prices for the parts required for the big block hub conversion, here they are for future reference.

Modified Cover: 925512 - $265.78
Big block hub: 916048B - $125.80 (6 bolt pattern Chevrolet)
Balancer shell: 917074 - $376.03 (6 bolt pattern Chevrolet)
Bolt pack: 950201 - $9.75

Crank bolt not included with any of the above parts.

If anyone has any conflicting info to what I've posted here I'd love to hear it. I'll be having the order placed in the next few days or so.

What year cover are they using to modify?

I didn't ask, they didn't say. It will be easy to tell when it arrives as one will have the plug for the factory OBDII crank trigger, one will not.

I'm concerned with the different price that I have for the balancer shell as compared to what's above a post or two though. The one he told me I needed was a 6 bolt one he said...

The one he quoted me was by application a LS1 hub according to their sheet on their website. The guy (Rick) told me not to worry about that though, so :shrug:

I just hate sending **** back and waiting longer when they/I'm wrong though. Costs more that way too.

I didn't ask, they didn't say. It will be easy to tell when it arrives as one will have the plug for the factory OBDII crank trigger, one will not.

I'm concerned with the different price that I have for the balancer shell as compared to what's above a post or two though. The one he told me I needed was a 6 bolt one he said...

The one he quoted me was by application a LS1 hub according to their sheet on their website. The guy (Rick) told me not to worry about that though, so :shrug:

I just hate sending **** back and waiting longer when they/I'm wrong though. Costs more that way too.

For a '95 and up, the '96-'97 style should be used as there is more material on the cover for machining. I have a '95 and used the '96-'97 style and just plugged the crank sensor provision hole. On a '92-'94, it appears to have more material than the '95 style, but if you are heavily modifying a '92-'94, it would be in your best interest to upgrade to a vented opti-spark, which would require the later style cover, and in that case, just use the '96-'97 style. :)

Thanks for the advice. I'm on the fence on whether or not I'll be using the factory crank reluctor as a crank signal for the BS3, or using an aftermarket crank trigger. Regardless I'll be going with the 96-97 cover for more seal support. I'm pretty sure that's what ATI will send anyways, just need to confirm it before the order.

As for the opti, I'm going to be either eliminating it completely, and using a distributor stub for the cam signal, or modifying an opti to signal cam position. If I do use the opti though, I won't be using the optical portion of it, I'll have a VR sensor to do the job, so the opti will essentially be just a convenient place to mount it. :)

For a '95 and up, the '96-'97 style should be used as there is more material on the cover for machining. I have a '95 and used the '96-'97 style and just plugged the crank sensor provision hole. On a '92-'94, it appears to have more material than the '95 style, but if you are heavily modifying a '92-'94, it would be in your best interest to upgrade to a vented opti-spark, which would require the later style cover, and in that case, just use the '96-'97 style. :)

Ok, I have a '97 timing cover (GM12550032), and NAPA 22306. The NAPA oil seal has an outer diameter of 2.630".

Obviously I need to have the timing cover's bore enlarged... but to what size? I assume this is an interferance fit design. Would 2.625" be too small? Anyone want to share the final size they went with?

I'll probably just give the seal and cover to the machine shop and tell them to make it work :) but I'd like to see what others are boring out to first so I don't get too crazy. This is a rubber oil seal with a thin steel hoop; I imagine it needs more interferance than say a steel dowel needs just based on compression ability. That, and it's pretty wide so the interferance should be larger right?

5 thousandths enough? too much?

---------------------
Edit:
After a few replies, I'm going with 3 thousandths.

Also, Federal-Mogul makes an equivalent oil seal and it seems a bit sturdier comparing them side by side. It's NATIONAL 341022... same dimentions otherwise... just not as hollow in the rim and the rubber "lip" is thicker.

The stock cover's retaining lip is only 2.1" diameter and the new ATI hub OD is 2.25" (what they call "seal diameter")... so it needs to opened up to clear the hub. The lip you leave on there should be at least 2.30" to clear the hub and any mis-alignment, but no more than 2.40" or the seal may not stay put once you start pushing it in or pushing in the hub :)).

Someone here mentioned the stock bore is 0.400+" deep (mine was 0.410"), and the NAPA 22306 (and National 341022) are ~0.176-0.180" thick. He bored the stock cover out at the factory depth and used 2 seals, but you'll probably want to check your casting just to make sure there's enough beef there to avoid breaking through. I'm looking at a double seal but only boring down the 0.360" needed to flush-mount the seals... just as a precaution.