Broken SC Pulley?

Albertj: I needed to replace that idler anyway , so this really is only a minor setback when i break it down like that...the supercharger belt was only about 4k miles old though...

Derek: i don't think the intense is a bad product , it appeared very well made , things happen and intense made did more than they are responsible for anyway... I haven't heard enough about pulley boys to know whether they would do the same...they might. I don't know.

Corey: You're right. I shouldn't let this discourage me from modding.. this kind of thing happens when going fast , shit's gonna break.

Cheap , Fast , Reliable---- You can only pick two.

wow that really must have been a shock to see when you popped the hood. i remember my heart sinking when i shrapnel'd an idler and the belt ripped my PS pump a new one. i freaked out and thought i was leaking motor oil!!

are you going to change the belts and pulleys yourself? if you are, and can still drive the car N/A, wait til thursday and bring it to my place. i can do belts in no time now that i've done mine 4 seperate times.

Well it took out the accessory belt , so i might find a way to slip the accessory belt on and take you up on that. Sounds like a good deal , you change my belts , i tune your car.

Tony,

I was agreeing with you, Intense does make a good product and they stand by it. I was just defending my PB setup for no reason, people give me a lot of crap for it because it costs more than the Intense or ZZP pullies.

Doesn't matter what pulley you have, as long as it works.

I'm glad that I went with Intense, because that is great customer service. I've had good service from ZZP as well.

Hm.... I might get those screws from Aaron...

I'm with Aaron on this one. I doubt the pulley or screws were defective. Check that belt path with great care.

IT HAPPENED AGAIN!!!!

Well sort of. This time the pulley just fell off. And didn't take out any belts or anything thank god.

Anyway this time i place the fault on an idler that wasn't tightened down and was wobbling a little ... but i did notice something out of the ordinary...

There was this black goop on my pulley...and i don't like the looks or scent of it. I think theres only one thing it could be ,



And i'd like to know why. Also that plastic pin at the end that goes in that hole at the end of the snout is stuck in there ( tried to removie hub to put stock pulley back on....

So am i as screwed as i think i am?

sorry to hear all that, but at least you didnt lose the belts this time.
idler? you mean the tensioner pulley by the PS pump?
also, did those screws you had in there hold or did they just fall out?
i'd guess the black stuff is s/c bearing grease. you can buy rebuild kits with seals and stuff pretty cheap, but you need to have a press to install them. it'd be a good time to replace that rattling coupler too.

i dont think you're screwed, but i'd go ahead and replace any and all idler you can, get the snout rebuilt (or buy one) and take a closer look at that bad tensioner.

No it was the idler by the front of the motor. The 3in ribbed one... The bolt on it wasn't tight so the pulley was probably wobbling , probably why the belt jumped grooves that time.

Two of the screws broke off in the hub , one fell out.... so i have 4 broken screws in my hub....


I'm thinking i might just buy a complete ported blower instead , as i think with the money involved and the fact that its a planned mod anyway i might as well go for it.

The black is probably a mix of SC oil and belt shavings. The oil would be leaking because of the vibration and wobbling of the other pulley being defective.

You said there are now 4 broken bolts in your MPS? As in you didn't remove the prior broken ones before putting on the new pulley?

That combined with not checking the belt path for issues is what caused your failure this time. It's no wonder why it happened so quickly.

To get the plug out.. Lift one edge gently with a small screwdriver and hold the plug while turning the pulley/mps clockwise. This will back it out of the threads.

Lemme know if you want to sell that mps setup or the pulleys and SC if you are replacing it.

belt path was right, and i felt all of the idlers and they all had good bearings, no wobble or play. the only thing that worried me when we had everything back together was the tensioner by the PS pump was jumpy, like the tension wasnt adjusted, so i torqued it back and fourth to feel the spring, and when we started it up the next time it was fine.
IIRC 3 of the MPS screws broke in the hub, so he used 3 regular screws and washers to hold the pulley on until the zzp bolts came in today(?).
if the idler is wobblier now then it may be b/c the belt threw it off this time.

Well i bought a zzp outlet ported blower off of a guy on regalgs.org for 300 shipped with a 3.5" pulley , so i guess this all ended up being a good thing....

Bill yes i am willing to sell my blower with MPS hub attached to you.
PM and make an offer , i probably won't turn it down.

Same thing almost happened to me yesterday on my way home from work. A few background facts:

- haven't removed my SC pulley in a long time, probably more than a year.

- everything looked fine when I replaced the SC belt tensioner about 4 months ago.

- I used new ZZP SC pulley screws, without thread locker.

- yesterday just happened to be one of the hottest days of the year for us - 95ºF+ according to my dash.

So as I was leaving work, I came to a stop light and heard a chattering sound. It sounded like marbles in a can, but not a full can - maybe about 5-6 marbles. It also had an inconsistent frequency, like popcorn popping. I had a very hard time figuring out it was coming from under the hood, so I assumed it was another vehicle.

Drove another 25 miles at 60-75 mph. During the cruise, the noise completely went away, but once I slowed down to 10 mph, I heard it again. This time it seemed to be more consistent, and a bit louder. I sat at another light for about a minute, then pulled into a parking lot and popped the hood. The source of the noise was immediately obvious, so I shut the engine down. Here's what I found:





Fortunately, I caught this just before all heck broke loose. I can't believe those screws were still hanging on. I did have the correct allen key in a small box in the trunk, so I just screwed them back in and tightened everything. No problems since then.

Looking at what happened earlier in this thread, I can see how loosing a screw or two could lead to the pulley breaking off and leaving very little evidence behind. It seems just a little vibration can cause all of the screws to loosen and back out. Repetitive heating and cooling of the blower pulley and hub likely also contributed to this. Note the hub and screws is stainless steel, and the pulley is aluminum.

Just a heads up to everyone running the INTENSE MPS hub/pulley or ZZP screws - I'm putting some blue thread locker on all of these screws, and if you don't swap SC pulleys more than 3 times per year, I think it's smart insurance for all of us to do the same. I never had this issue with the INTENSE screws that came with the hub (however they did strip out more easily). I could fault the ZZP screws, but they technically weren't designed to work with the competitor's hub, so I guess it's just a little thread locker and problem solved.

Anyway, check your MPS screws at least once per year, or use a medium thread locker to prevent a catastrophe under the hood.

Jesus man. That ain't right. Almost makes me glad mine is press-on lol. Glad you found it before them 3 came out and broke the other 2.....

AA fwiw i had an intense hub with intense screws when it happened to me. I've had a zzp hub on this blower for while with zzp screws and have had no issues so far. Not saying its intenses pulley system at fault, just that it probably wasn't the screws. Glad you caught it in time as it is not fun digging out old screws from the hub.

there is nifty little product called "locktite" it works great . ive used it for so many applications.

^^^ I have some blue Loctite in my cabinet, too. I use it for bolts that I'm worried about coming loose, but never thought to use it on a modular pulley system until now. The vendors of these products do not say to use thread locker, and I'd think sure 99% of people running MPS don't use Loctite - maybe I'm wrong?

I don't use Loctite on my lug nuts, same kind of thing.

Anyone think it has to do with the direction of the belt route? All of the idler & tensioner pulleys are reverse thread... What about the type of screw, thread pitch, mating surfaces? Is there a more suitable fastener that would work better?

I'm going to write to a few of the vendors and see what they think.

Thing about lug nuts.....they never have a constantly changing back and forth torque on them. They are either going forward or reverse. The MPS hub has constantly changing torque on it. As the engine misfires at idle, that pulley has a constant "start-stop" effect to it. Good example: when the S/C coupler goes bad, you only hear it at an idle. All other times it doesn't make a peep because it has tension on it. This back and forth motion would explain why those hub bolts came loose (and causes the coupler to FA!L). IMO ZZP should recommend a loctite for this application, it only makes sense.

I guess I'll pop the hood before I leave...

I haven't had a screw out since December, and my memory is only good for about 12 seconds anyway. Are these things long enough to put lock-washers on? I don't know why they would recommend against Loctite, but perhaps star-washers would be the way to go?

Quote :

Thing about lug nuts.....they never have a constantly changing back and forth torque on them. They are either going forward or reverse. The MPS hub has constantly changing torque on it. As the engine misfires at idle, that pulley has a constant "start-stop" effect to it.

Doesn't a wheel go through the same kind of torque changing when subject to acceleration and braking? Add in forces from the suspension when cornering, and heat... there's a parallel, imo.

There must have been some concern, as all Chrysler cars used reversed thread lugs on the left wheels during the '60s. The newer style lugs don't do this, perhaps it's the way the nut seat is tapered against the wheel?

Or perhaps it's the way the lugs are slammed with 100 foot-pounds or more from an impact gun...

What that says to me is the MPS screws may bee too small for their application.

Time to recheck my screws...

lol the fear has been put into everyone

Abaddon wrote:

lol the fear has been put into everyone

...at least, everyone who has a screw loose



Albertj