rflow306

Another crank-pulley issue

http://mymbonline.com/forum/viewtopic.php?t=7558

You have to be careful and make sure you follow the correct instructions. The first time I changed mine I also did not change the crank bolt, because my wis was an older version which did not call for a new bolt.

jangy

His issue wasn't just the bolt. They did not TQ it down nearly enough the first time. The scary thing is that any tuner would know how tight that should be (ball park).

Jakpro1

My tech Ken was having panic attacks when I told him guys were using the crank pulley over again.

He's like, noooooooooooooooooooooooo!!!

Fast55

You can re-use the pulley, but not the bolt.

Jakpro1

Typed too fast Meant stretch bolt.

Vadim @ FD

If pulley fell of, it is not just a bolt issue........................ it was not installed correctly and I mean woodruf key misalignment.

ScottCLS55

+1 I don't think the stretched bolt is the main cause of pulley falling off in these cases we are hearing of.

The people are not marking the crank woodruf key since you can't really see it when putting the pulley on. You must use mirrors and mark and then feel it slide on. I think these guys with problems are thinking its on the key and then tightening it down, the key will smash only to a certain point and the pulley not sit flushwith the crank. Then vibration from the engine will cause the key to futher disintegrate and them the torque on the bolt is lost and it comes loose and pulley falls off..

If you can find the woodruff key of any of these cars it will be smashed in to bits by improper install.

If your pulley falls off in 6 months, its probably the bolts fault.(again odds are very low but possible) I buy the bolt when replacing mine, but I think "the bolt" is getting a bad rap here and had to say something. I hope its not because the bolt is black.

jangy

also, bad balance on the pulley can do that.

dyno

did you ever check for proper balancing of your modded pulley?

I did it for a larger pulley (clutch-style, with springs inside) and was not correctly balanced and, further, was not steady ..
monday Im going to do the same with stock pulley .. just for comparison

jangy

Nope, I never touched the pulley. I would assume verifying proper balancing would be between Renntech and Creative. I personally think that is a huge issue and that people don't think about it enough. that is a heavy part and spins FAST!

dyno

.. huge difference in weight, too
this is a 172mm pulley,about 3kgs, while 157 stock is 4.74 ... don't know what it implies

jangy

I've always wanted to experiment with weight of the pulley. some say it needs to be there. i'm not so sure. I see were we need the STRENGTH, BUT WHY THE WEIGHT? Is it actually anything compared to all the other weight that it is tied to?

dyno

yes, I think so, too.

for sure lighter pulley means quicker spinning
but overall balancing must be an issue..

then, we have the why not issue for a simple solid pulley
..
think I'll soon go for a supercharger pulley, instead

jangy

a solid pulley wouldn't have any dampening to it at all and would likely wrench the crap out of stuff at some point.

Going after the SC pulley is scary just because of the clutch and associated electronics. I would be curious to know where the AMG Sc stands versus other tuners? Is there one out there that doesn't drain 100HP to spin? I'm sure those of us with larger pulleys are putting even more drag on the motor.

Vadim @ FD

I already tried solid pulley on 55s back in 2003. After 100 miles the pulley would have a damaged woodruf key opening from harmonics.

Interestingly enough I had a solid pulley on my C32 for close to 100K miles and not a single problem.

As far as SC pulley, two problems - if you were to make it smaller, there is no room for the bearing and secondly making it smaller also reduces belt surface area leading to slippage.

I am working on another solution to adding more boost with lighter weight and easier installation. I will post details later.

Stay Tuned.

dyno

as far as I know, Jaguars are tuned to solid pulleys without problems
... but I'm not going to test it

indeed, I don't like large pulleys rotating, too
also because with stock setup it's possible to obtain nearly 2psi more boost by proper tuning only (.. don't know how it is done but I suspect by-pass and egr valves play a role)

SC pulley: seem to be "usual" enough that mod in Germany ... even if perceived as "hard"
.. didn't anybody check yet if for example the Slr or W221 have the same SC pulley part as ours ?

psk145

for what its worth. Im on my 3rd pulley with the same bolt. After the intial backout on the freeway after Creative's install, it hasnt came out since.

Vadim @ FD

Charles, do not neglect it. It will either be new bolt or new crank.

psk145

I know I know. Next time I take it in for service I'll take it to Assan who's at fletcher now, and have him put a new bolt in.

RoydRage

Vadim is Exactly correct... This is the very point I was going to make while reading the earlier posts. The belt would also have a tighter turn to make increasing friction.

And Vadim... If you could clearify... I heard 2 different proceedures. 250ftlbs. or 150 + 1/4 turn... this seems vague.

Thank God Back To Tech Stuff!

Best,

RoydRage

BrianS

This should help answer some questions....

jmf003

FWIW, AllData says it's 200 NM (= 147 ft lbs) + 90 degrees (= 1/4 turn).

ScottCLS55

Is the woodruff key replaceable in our crank like Chevys and fords and such? Or is it welded in place?

I have replaced a lot of Ford Crank pulleys and you can change the key when you do it. Is the Mercedes the same??

Does MB have a part # for the woodruff key??

jangy

It is replaceable. There is a groove in the vrank that it sits in and is held in place by the main seal.

The problem becomes if the pulley itself literally melted onto the crank. You will have a hard time properly cleaning the crank, although it can be done. Also, replace the main seal. Another potential problem is that the key may be jammed into the crank, even after you get the seal off.