Well I have been trying to lower my spot on the FI list and the car is making more power than before thanks to the MMS CP but this is where I am running into problems.
Before I start I am in no way flamming mike or MMS their products are top notch and I stand by them THANKS.

Well since I put the MMS CP on I have snapped two gatorbacks at the track, both on the second pass and both were slipping like mad. So while I am under the car replacing the belt with a NAPA belt recommended by mike@mms I noticed that the pins on the MMS CP were gone, two were snapped and one is MIA. The spokes of the stock LS1 CP are friggin indented pretty fierce by the impact of the pins on them. This leads me to believe that the MMS pulley is spinning somehow or both are at different rates. I don't have the LS1 CP pinned as I was going to do this on the new motor sittining the garage. I put the MMS pulley on while the car was on the lift so I got a good visual on the pins engaging the spokes when we put it on and we torqued the crank bolt down with the MMS recommended torque settings to be sure it was going to stay in place and yep thread lock was used. So what gives, the car is making awesome power and will definately fly but I can't get the belts to stay on and now this.
With the stock ATI set up I never had an issue with belt slip/belt breakage with the gatorbacks, I ran 9psi till I lifted.

Here are some specifics on the set up.
MMS CP
ATI 3.4 pulley (when not slipping I see 12-13psi up here at 5600ft)
No pin in the crank
WAS using gatorbacks
Belt tension is set just like I had it with the stock ATI pulley
Crank bolt is still tight as HELL.
Belt is 40inches long and still have plenty of room on the ATI tensioner to tighten it down so I know the belt isn't too big or too small.

Could it be that the ATI crank bolt is still too long. They said I didn't have to worry about this because they had this problem solved by the time I got the kit from them ( I still put a washer on the bolt just in case)
Could the LS1 CP and the MMS pulley be spinning at different rates on the crank when she comes under boost, causing the belt slip and breakage/pin shearing? With the way the belt is tightened down I should be seeing NO slip under boost.
The MMS pulley looks like its wobbling around when the engine is running. Was wobbling when it was first installed or after the first belt break.
I emailed mike for some new pins so that will be fixed asap.
Should I run the car with this happening. My gut instinct says NO, but I now have to work way out of town (40mi round trip) and she is my only car. I didn't tighten the belt like I have been doing to save some stress on the MMS pulley and S/C.
MAN this is pissing me off, I just want to move down on the FI list, lol.
frcefed98 is going to sell this car and buy a SRT-4 if I keep having problems like this
HELP

 

ttt

 

are you sure both pullies ( blower and MMS) are alligned. if they aren't , use shimms to relocate the blower bracket back or forth as needed.

 

Yep the are aligned. Nothing was changed on the bracket when switching from the stock ATI CP to the MMS CP, just the pullies themselves. Mike said they are a direct swap. The bracket standoffs were never removed as that is not related to swapping the pullies out and changing the belts. I didn't have this problem with the stock ATI CP. So probably isn't the alignment. I never broke a belt with the ATI CP.
1dirty thanks tho, you have always been the first to help me out, when I had belt slip you told me about how tight to get the tensioner and to use a good amount belt dressing to get rid of the belt slip.
I use to laugh at the guys that were having problems with slip and belt breakage and now I am one of them. Damn the Karma

 

When you run a belt a bit before it breaks (or looking at a broken one) do you notice any excessive wear on one side or another - that would be a sure indication of an alignment issue (just because things haven't been changed from stock doesn't mean there isn't an issue - you can use a straight endge and make sure everything is on the same plane).

The wobble on the crankshaft pulley does seem strange - if you can you might take it off and bring it to a machine shop. Have it spun up on a lathe and check it for runout (might as well check the balance also).

The pinning (or if you build a new motor get it double keyed) is definitelya good idea, but I don't *think* it would be causing the issue you are having directly. You might pull off the pulley and check to make sure it doens't look like it is spinning on the crank also.

The final possibility is bracket flex - I believe a few others have already run into this issue. Your alignment can be great normally, but under load the bracket will move out of alignment.

 

Are you using the ATI supplied crank bolt? If so, does the MMS pully recess the same depth as the ATI Crank pully supplied with the blower? If so then you might want to throw 3 or 4 washers on there. the ATI bolt is a little too long and might be bottoming out at the back of the crank thread. So even if you put 150+ ft/lbs of torque on the bolt, if it bottomed out the MMS pully might only be seeing a small fraction of the torque.

Just a suggestion. I spun the ATI crank, this cured my problem.

Mike

 

[quote]
I put the MMS pulley on while the car was on the lift so I got a good visual on the pins engaging the spokes when we put it on the car

Are you sure the pins were resting on the correct side of the CP? If not they would have that entire gap in the spoke to pick up speed and shear the pins on the MMS CP. Could be why the CP has such prominent indentations in it.



Could the LS1 CP and the MMS pulley be spinning at different rates on the crank when she comes under boost, causing the belt slip and breakage/pin shearing?

If theres no pins I would assume thats where your losing boost.CP is spinning faster than the MMS pulley and could be building excessive heat leading to pre-mature belt faliure. I lost a couple belts when I swapped to the steel idler pulley. The extra mass of the steel idler would let it spin faster than the belt during shifts and engine braking causing it to heat up and eat through the belt. Just a thought.



The MMS pulley looks like its wobbling around when the engine is running. Was wobbling when it was first installed or after the first belt break.

The wobble probably came from the force of the pins being sheared off.



Should I run the car with this happening. My gut instinct says NO, but I now have to work way out of town (40mi round trip) and she is my only car.

I wouldn't run it with the blower connected until you fix it. Just disconnect the belt and the two hoses into the air box.Basically going back to N/A. As long as its not to dusty where you drive I wouldn't worry about sucking anything in there. If your worried you can clamp a couple screens across the air box openings.
Hope I helped ya.
[quote]

 

I'm having a problem with my belts shredding too....I'm running an 8 rib setup...one side of the belt frays, but not the other, I think this happens under load though because the brackets are flexing...

 

Thanks for all the suggestions guys, well I have ruled some of these out:
The pulleys are perfectly allgned. The belts are just snapping cleanly, no shreading so this leads me to the shock of a spinning LS1 CP and or the S/C CP. When the pulleys catch they snap the belt. If the bolt was too long I would have had the same issue with the ATI CP that I am having with the MMS one. It has to be the boost level(was 9psi now 12-13psi very quickly MMS pulley rocks) that I am running its putting too much stress on both the LS1 CP and the S/C CP causing them to spin on the crank. I will remedy this as I have ordered a pinning kit for the pulleys. I have thrown out a theory to mike@mms and he liked my thoughts. I will try out my fix that I discussed with mike@mms and if it works I will post my fix on here.

SSmokin good advice I had to follow my guts so I
didn't run the car today, just didn't want to screw things up any further. I agree on the cause of the wobble, there are no pins holding the thing still so it is moving around some.

Bigbos this can also be an issue to what I am seeing. The brackets flex way too easy. I don't see it as the bracket itself but the 3 flimsy little bolts and aluminum standoffs that they provide. Too bad they don't have another bracket or brace to help those 3 bolts from flexing. Anyone with a lathe wanting to make a brace or support bracket for the ATI kit?
I'll keep you posted,
Jeremy

 

BTW we torqued the stock ATI pulley only to 175lb ft. This is all we could muster in the driveway, lol
The MMS pulley was installed on a lift and we torqued that mother to a full 225lb ft Its nice to have the car over your head while you stand under it. Also good to have a huge friend(thanks neal) to hold the prybar in the flexplate so we could get it to 225lb ft. Now time to go fix this problem and drop a space or two on the FI list or blow it up trying

 

I don't think it is the MMS CP, as far as knocking out pins are concerned... I've done that with the ATI pulley when I took it to 10 PSI.

I had/have this problem, too.
More power is produced. More rotational force / torque is there, now. My next thing is to get a new bolt. Re-using the same bolt can contribute. But, I found mine was wobbling because tightening the bolt down, it was bottoming out, where it did not do that with the ATI pulley before. I put another washer on, but that defeats my fix before where using only one washer helped keep the bolt from backing out.

I think I'll check and see if the area where the bolt meets the pulley is indeed thinner than the ATI supplied pulley, as was suggested to check above.

I saw where even the one washer was wallowed down, and thought maybe I had cut the bolt just that close to bottoming out. I'm dead in the water until I resolve this (got my tranny back in and my overhauled D-1SC back on). I just have to resolve this before I start tuning to see if I can run 10 PSI or greater again.

 

I do not hear the Vortech people complaining as much about their belts slipping. Whats the deal?

 

As far as I know it's for two reasons. One, the Vortech kit comes with a better idler pully. There's is spring loaded to keep a constant pressure. Ours is bolt tightened and when the belt loosens over time the torque makes it slip. The second reason is the ATI head unit flows more air. I've heard rumors that vortech's 9 lb. kit only puts out 6 lbs. Now granted psi doesn't neccessarily directly coorelate to cfm. But it indicates that the ATI is probably flowing more.

I think a combination of those two things is why the ATI blowers have slippage issues.

Mike

 

Thats because the V9 kit doesn't have belt slippage issues (hello tensioner). I never had a belt slippage problem on 8PSI, and now on 10PSI, I don't notice any boost loss because of belt slippage (quite the contrary ). As soon as I get my crankshaft keyed, and my fuel pump straightened out I'll have some new dyno numbers (closer to 600RWHP) and finally some track times. And NO BELT SLIPPAGE. People talk about how the Vortech kit is "weak", but when set up properly with good flowing heads and a blower cam, and enough fuel, its easily a 10-second kit.
Besides, what good is monster HP and TQ when your belt slips and you can't even use it anyway?
Good luck on figuring out the LS1 ProCharger belt issues.

 

To continue troubleshooting the issue.. Who has run 12lbs plus on a Vortech w/out a cog setup and no slipping? Maybe scottws6 can chime in with his no slip belt..

 

I'm running a very similar setup to scott WS6, his is working for some reason, flawless...

I'm going to have Sikora do something to support my brackets, and maybe have a better tensioner made, my pulleys are suppously perfeclty aligned too, with a straight edge...

I will keep you updated...

 

1) ATI uses 6 rib setup. and Vortech uses an 8 rib setup.

2) Some tensioners are not as good as others. If you can take the blower belt, and twist it around, like 90 degrees, then you need more tension. I have a custom made tensioner that is adjustable.

 

I can see why you went with Vortech John..

 

PSJ's kit is almost completely custom AFAIK so blower choice probably didn't have anything to do with Vortechs or ATIs street car setups.

I think John has contacts at Vortech is his main reason for going that route but, I don't know for sure.

 

Ahh after a long day of messing with it here is what I found
and this
and for the rest of the pics go click on these links.
sheared pin
LS1 Hub Center
fixed and locked
This pic shows how I utilized the new "groove" in the spokes as locators on for the pins. I did shorten the bolt 3 threads with my dremel (gotta love the dremel) but the pulleys went back together like before the cutting began. I did have to clean up the shreaded and balled up aluminum on the MMS pulley with a 80 grit flap wheel. I sanded the bottom of the MMS pulley flat as the aluminum pushed up on it. I also found the dowels(1/4in BTW) at a local bolt store. 10 for 10bucks just in case I have to do this again. I clocked the MMS Pulley clockwise instead of counterclock wise that ATI calls for in there instruction booklet. My reasoning is that the engine spins clockwise and without the pulley being keyed or bolted down, when the car is under a great shockload like a burnout or launch the MMS pulley will spin clockwise and shear the pins off the pulley. I'll give it hell and see if it holds....
Thanks for all the help and recommendations,
J