Benztech858

I told myself I wasn't going to upgrade the supercharger pulley on my E55. A new stock one from Benz is over $1000 and an aftermarket smaller one is ~$400 so I bought the 83mm. I installed the pulley with no shims and measured the gap, it was over 0.60." I have been driving it for a few months and notice when the supercharger engages it is very abrupt and causing the vehicle to hesitate/lunge forward. Should I try installing one shim and see if that makes it better? Anyone have any experiences with this? Does anyone know of an aftermarket stock size pulley option?

bayhas

The gap specs are 0.35mm to 0.45mm
if your gap is too low, then you need shims, otherwise, shims will introduce slippage, and wear down your clutch. In your case, shims will make it even worse. Why did you need to replace your factory pulley to begin with?

Assuming you meant gap is over 0.060", that is more than 1.5mm, I am surprised your clutch is even engaging at this point, and it sounds like you need an electromagnetic plate from the dealer.
Did you get proper tune along with the pulley? this is not a plug and play mod, and needs supporting mods, including cooling, tune, and recommended belt wrap kit.

cnterline

.60 is too much ,the hesitating and lunging is the s/c engaging at a faster speed then before causing that feeling,the trade off for more boost ��

Notdke9fdkfjekrjrkj123

I had the same problem with my 83mm pulley,had to machine down the outer ring of the bearing to get a smaller gap,

kenneyd

My stock one was shimmed, and the cleanance was more than spec. I had noticeable SC engagements and a loud squeak.
I installed my 83mm and found the clearance to be exact with NO shims.

MACEDON

You sure you're measuring correctly?

I'd take it off, add a shim, see how it feels. If it's worse take it off and seek another solution.

I assume you tuned your car after the installation?

bayhas

I dont think "feeling" and trial and error is a wise approach, as increasing gap with shim to even more than 1.6mm gap will make the clutch slip further, and make the problem worse.

With this much gap, any further slippage will kill the plate, as the more the gap is increased, the higher speed friction will occur, thermal energy dissipated by friction is exponential, not linear, so it will eat the plate much quicker to increase gap.

Specs are very specific, and I dont think there are more than one way to stick a feeler gauge in between clutch and plate.

Benztech858

I am not the smartest guy but I removed the stock pulley with 2 shims and installed a brand new one with 0 shims and the tolerance is too large. Sounds to me like the magnetic clutch is fine. In my 12 years at Benz I have never seen the magnetic part of the supercharger fail. It clearly has to do with the bearing placement in the pulley. I am extremely disappointed in the quality but it is what it is. I will install the stock pulley back on this weekend and do some measuring. Thanks!

Benztech858

Here are the differences between the stock pulley and 83mm pulley installed with zero shims.


83mm


Stock

bayhas

very interesting, where did you buy your 83mm pulley from?

bayhas

A bearing with become junk if it comes near a lathe, as shavings WILL make their way inside the cage, no matter what you try, and either kill it within few spins, or significantly shortening its service life,

If this is a design flaw, we need to either machine the pulley itself (buttom of the cup where bearing sits, so it will sit deeper into the pulley, dont think there is enough meat to grind though), or use thinner bearing (not sure if it exists)

Benztech858

Purchase from UPD. I know they make quality products that's why I was so surprised when I installed it.

bayhas

Spoke to @shardul yesterday, he brought to my attention a very good point, that pulley springs sag and reseat themselves over time (10-15 years), causing the friction plate to back further closer to the supercharger pulley.

This a beneficial wear by design, as it compensates for wear in friction material of SC plate. This is why Mercedes recommends replacing the belt pulley and friction pulley in pairs, because if you install new belt pulley on worn plate, you'll see huge gap (this is what we're seeing) and vise versa, if you replace the SC pulley, gap will be very small, albeit you can fix lack of gap with shims, but up to a certain extent of wear on the plate, before it starts slipping, regardless of gap, due to wear.

I think the case is closed for me, I ll continue to use the 83mm pulley despite my 0.9mm gap, I ll monitor it as the pulley ages, and see if it goes down, however, if I start seeing slippage or lack of boost, I ll replace the SC pulley plate.

bayhas

In fact, funny enough, you can see the sagging Shardul described in the picture above, look at the gap between silver portion and springs in second picture, and lack thereof in the first

tw2

So possibly an issue for some high mileage cars where people want to upgrade?

bayhas

Yes, mileage, age, and mostly driving habits all play a role

best recommendation (not cheapest) is when in doubt, replace both pulleys at the same time, that’s the Mercedes way

however, it’s probably better off riding what’s left of the clutch, and not replace it unless there is an actual problem (slippage)

WillyG

Might be a little off the topic, but is anyone checking their gap after a hard pull? Or just cold?

bayhas

Typical check is cold. WIS does not suggest there is a difference, but for sake of knowledge, I will see if there is a difference.

GinDistiller

Bumping this thread from the past...was there ever a 'solid' solution to fixing the UDP pulley's large gap? Mine has 147k on the clock, put a slightly used (5k mile) UDP pulley on it a while back and with no shims the gap was large, like .5-.6. Engagement is still rough at times and measuring now it looks like not much has changed.

Is every aftermarket pulley going to be like this? If so I may just toss my stock one back on, but I do like the added power of this one.

Any input is appreciated!

Fountain35

How is the friction pulley replaced and I wonder what it runs $$$? It may be worth doing both too see if the problem goes away.

GinDistiller

I wondered the same thing. I'm guessing the s/c has to come off, and I already did that once this year, so I'd probably opt for my stock pulley

tw2

I haven't looked at the bottom of the pulley for a while but my guess is you either take some material off the bearing or machine the pulley so the bearing sits slightly deeper in. The circlip notch would need machining with a slightly thicker circlip. I don't know if these are feasible. Hopefully they have corrected the issue. It is easy to add shims, you can't take away zero shims.

SICAMG

Easy fix. Remove bearing, machine surface, bearing race, to what ever you need, reinstall bearing, reinstall pulley.
Will work perfect.

Baltistyle

old pulley (5k ish miles). gap way out. You can see the springs are not fully retracted.

new pulley gap even worse.

I posted a thread a few weeks ago trying to find why my supercharger was starting to make a horrible noise, which to me was coming from the spacing of the pulley. Im familiar with spacing these and do lots of mechanical work so am familiar with operational concepts. Im also familiar with chirp, squeak, and slip noises and smells with this car. Its an 04 0280 supercharger with 142k miles and Ive had it five years.

When I originally got this pulley in Dec of 17 I inquired about the too large of a gap issue and was told it would be fine. About 5000 - 7500 miles later, this spring, the engagement sounded terrible and this is when I posted some pics of the pulley and clutch surfaces. From this thread I was told use a BWK and the spacing was still a non issue.

I purchased a upd bwk and another new 83 pulley and belt. I also separately ordered a double idler and a tensioner. The old pulley surface seemed ok, no cracks and the bearing was as new. It did have some rust and accumulated metal in the void spaces of the rivets which meant to means it was chewing into the metallic part of the clutch from hitting too hard.


Here is the order of installation to find what if anything was the fix.

First, No noise when the belt is off the supercharger.
New green belt, Double idler and tensioner. Still makes too much noise.
New Pulley and BWK and included black belt. Still makes too much noise. And you can hear the BWK makes things tight

I have included pictures of the old 84 and the new. The old still has too large a gap but has closed a bunch with some use. The new pulley is nowhere near being an acceptable clearance.

I need to figure out if the issue is the pulley not being machined correctly or if the clutch is worn beyond its lifespan.

Being that this pulley is still being sold (please do not eviserate me for this, I can promise 100% I know how to research and deduce), and machining is the proper way to fix the error, what is the proper depth to machine and who can provide this service at a cost that still makes purchasing these pulleys a good choice if they do indeed need to be machined specifically to a depth compatible to a used supercharger.

What is the proper depth supposed to be from the face of the pulley surface to the face of the bearing? Would this be the same distance as the length of the step on the supercharger snout minus acceptable gap?

Last questions. Does anyone know a part number for the supercharger clutch friction surface? I have seen pics and videos with them removed with statements that they do go back on. Is there a width of the super charger clutch where if it was too worn, a measurement would show this? I have to believe that since these can be rebuilt, someone has r and r'd the clutch.

OR is there a product out there that will provide the proper gap?

Im sure theres many more of us that could use info and measurements so that we may keep these platforms alive without locking up the supercharger since thats going to require a rebuild even quicker.

Thanks everyone

GinDistiller

Definitely good questions and glad to know I'm not alone! So I pulled off my 83 pulley today to see what I could do, trying to dremel material off the inner race surface of the bearing in place just wasn't going to work (not that I didn't try!). Measuring the difference between my 140k-ish stock pulley from the clutch surface to the inner face of the bearing and comparing it to the new-ish 83 pulley there is about a .3" difference, which explains the issue.

So, based on this, I would condemn the pulley as being manufactured incorrectly, at least for applications other than on brand new superchargers. Is it more likely that the magnet surface somehow receded .3" over the years, or that the new pulley is just too tight and the bearing race needs to be set a little further out? You can always add shims, these pulleys really need to be a little 'longer'. My stock pulley had the bearing replaced shortly before I purchased it, and the numbers are identical on both my pulleys, so that isn't the issue.

I put my stock pulley back on, shifting and engagement were instantly spot on (although I did miss the extra power..). Gapped at about .4" with only 1 shim installed.

There isn't a LOT of room to machine surface off of the bearing race...I'm wondering if I can remove and put the circlip on a lathe, take the material off there. It would fit looser in the channel, but once the bearing is pressed in and the slack taken up with the pulley torqued on, maybe that's all it needs.

Maybe I just need to sell my pulleys and put that $ away for long tubes and injectors and call it a day