she is definitely double stacked. lol. I like coco better.

 

now I know theres no double stacked just stacked unless your talking about her.

 

I mounted the prototype scattershield this morning. Seems to fit well. Being a proto, I bent the loop by hand; next go-round should be machine formed.

The intention is to contain pieces of the SC pulley clutch in the event of a catastrophic failure. To save the hood, the oil cooler and the air injection pipe. I chose to make it light rather than heavy. Adding the scattershield adds only 7 or so total ounces (3 for the part and 4 for the bolts and washers )

The only part at this point that bothers me is the hardware. M12-1.5 (the thread of the existing "lift-holes" in the supercharger) is an odd, in between, size. Looking for Stainless button head, or anything aside from the 8.8 std hex head (in a 20mm length) has been fruitless. Perhaps an OE application specific bolt (seat belt bolt, etc) or even a motorcycle dress-up bolt, etc may turn up. In the meantime, this is all I could find.

If anyone has some input as to an actual source for more suitable hardware (button head, low-profile socket head, flange head, or even std socket head ... I would love to hear it.

Cheers,
Chris

 

I think you're going to have to pack up and ship me a LM21 Pulley Saver Kit when the scatter shield is ready.

 

Great looking fabrication. Those that are committed to parts that might grenade will want one. Frankly, I'd remove the grenade and replace it with a "safer" pulley of some sort. Yeah, look who's talking.

Les

 

can do cousin

 

Thanks Les, I appreciate the kind words.

I tend to agree with your thoughts on using a safer grenade. But, I had a OE Mercedes SC pulley come apart on my SL55 so this is not unique to the Karmen pulley ... Perhaps it failed because it is asked to do more work due to the larger crank pulley? My first SLK32 (which my son drives now) has a stock sc pulley and a 181 crank ... it will get a shield too. My goal was to make it effective, light, easy to install and good looking ... I like to think I succeeded.

Cheers,
Chris

 

Only SS Socket Cap I could find anywhere. Britain!

M12 x 1.50 x 20mm Socket Capscrew A2

Mike S

 

Follow up with Khang Vo . . .

As this 62mm Karmen supercharger pulley project was over some time ago, he does not have a replacement pulley immediately available. He offered to take the pulley off his own car and swap with me but after some back and forth communications I've decided to wait for this . . .

Khang Vo's e-mail from 08/07/14

I'm starting process of making some more plates and these plates will be better than the previous plates. My current estimate is that it will take 3 weeks. Once it's done, you can send your pulley in for an upgrade. Again, sorry for the inconvenience. I'm trying my best to make sure people can enjoy the Karmen pulleys for years to come.

Just keeping you advised . . .

 

NICE JOB! Put me down to buy one when they are ready to ship . . .

 

My pulley looks fine. I will data a run now that some feel it is slipping. I guess that is a possibility. I don't run shims on mine. As long as I can stop the pulley from spinning at idle with my hand, I am good with it. I like the shield chris has come up with, and there are a few specialty bolt shops around here, so I will see what I can come up with. Chrome hex head maybe? Later...going to the Moto GP race....

 

MORE BAD NEWS . . .

I removed the 62mm Karmen supercharger pulley today . . . clear evidence of slippage and heat damage.

dcp_4793_zpsa49ab4a9.jpg

dcp_4796_zpsc749df37.jpg

Worst of all, the electromagnet on my supercharger is also damaged!

dcp_4792_zps0de04195.jpg

Does anyone know how to remove that part?? Any thoughts on where I might find a replacement?

 

This is what it looks like from the inside. Maybe it comes off by loosening the part from inside, but it looks kind of solidly fixed.
I have pics of a SC dis-assembled.
Click

 

Thanks for those photos Dave. Now I can see what might need to be done. Looks like I'll need to find someone with a broken supercharger and just swap out the entire face plate piece with the guts . . . That will also give me an excuse to change the jet oil in there too.

I've got an e-mail in to Rob at Needswings to see what assistance he might be able to offer . . . I should probably e-mail Rudy too and see if he has the parts I need.

 

ouch, I would like to see some more pictures before I give it a death sentence but I have never seen just the front half of these superchargers for sale before, you will most likely need to get a new sc and either mix n match or just use the entire used one. the good news is that they are not that expensive as there seems to be more supply than demand for them. see what the guy that sold you the pulley has to say and let us know, if you end up fixing it yourself we can get you everything you will need.

 

Makes me wonder how many other pulleys are going the same way.
If the magnets only good for standard torque and we crank it to +150% of that - it may be slipping more than we think.
1) how to measure slip?
2) how to improve if needed?

I'm not sure what stopping it by hand at idle means ...? Is that with an engaged magnet or not?
I recall from Woody's LED test that the magnet stays engaged once over 2000rpm in Drive and until the car is turned off (but don't quote me)

 

Do you know if the electromagnet still works?
That filler over the coils that is missing looks like a paste that was used to fill voids in some heating equipment we built. I have forgot the name though, it was like a steel/epoxy compound. As the surfaces of the mating faces deteriorated the slippage would get worse I'd guess.
If the clutch stays engaged after it has been used once, why do we need a clutch.
Let's face it weld is cheaper than a new SC.

 

I have 62 and now you all have me scared to drive the car with it on.

 

Yes the electromagnet does work and that stuff in the cut out areas does look like some sort of a paste that was applied there. Here is a zoom in photo of the electromagnet surface.

01bcaa70-1406-4f21-a446-d094b86adf27_zps354fc30e.jpg

Anybody have more information on that theory that it is an epoxy paste filler or does anyone know how the surface of the magnet could be repaired / refinished??

 

I don't have any specific info for you but you can try a local NJ company that may be able to help you. Electroid | INNOVATIVE ENGINEERING