benz_addict

Symptoms: Blowing bad blue and black smoke, car shutting off on it's own, bad shaking, misfiring and extremely low power.
Did a compression and leak down test found out cylinder #6 has extremely low compression.
Engine has to come apart...

Tow it home:


Intake box and sumps off and supercharger coming out:



Cylinder head coming out:


Cylinder head out:


Steering rack had to come out to push the #6 piston out. Also the lower oil pan had to come out.



Oil pan and oil pump out:


Undo the bolts and push piston out:


Piston out:


Here is a picture of the damaged piston rings and piston it self. Good thing the main block is OK, talk about luck?



Shopping for a new piston... please PM

E55Bullet

How the hell did that happen?

blackbenzz

Sorry to hear. Thanks for the pics though. Did you coat your sc with something or just paint it?

benz_addict

Combination of high kilometers, daily beating, track use and most of all bad tuning with the new pulley.
I painted the supercharger with high heat flat black paint. It tends to chip though.

Can anyone confirm our 55k piston size is 97mm? Same size as the 500 M113 motor? Trying to locate some pistons...

jamusa

Had basically the same thing happened to me afew months ago on my 03 E55,only it was #8 piston and ring,installed a G-55 motor.The car run true and strong like before,or maybe even a little stronger.While the car was down,i contemplated on doing some head work,but decided to do it later,because i had a spare motor that i can do all types of R&D on.I'm thinking on doing a 3" cat back system,and deleting both sets of cats,but before i do so i need to check out those small cats the size of an 02 sensor,that take the place of the cats.I wave a friend running the same set up(3"cat back system with "h"pipe on his 2007 M6 with over 1000 miles since installation,with no cell light and he is enjoying it.

Tech-Tune

Same exact thing happen to me (cylinders 5 + 8).
I've decided to go with forged pistons this time around.

Tech-Tune

97mm is correct BTW.

Benz-O-Rama

Ouch! Sorry to hear.

Who's tune was on the ECU when it failed?

benz_addict

Should I be worried about the other pistons failing then? I really don't want to rip it all apart if this happens again. The tune was someone here local, no one from here on MBWorld so no worries, it was just a matter of time I knew it was going to happen. I also had to replace the failing head gasket I was putting off.

Any suggestions where I should purchase the piston? I'm interested in the forged piston tech tune

Benz-O-Rama

Try my buddy Pat at the Maryland location of www.pgauto.com

Tell him Clayton sent you. It's a long shot, but they sometimes have M113 long blocks there.

Good luck.

benz_addict

Thanks!

Benz-O-Rama

I just talked to a benz mechanic and he says the OEM pistons will be 4-5 hundred each, $USD

loungn14

when you get her back together let me know. I will tune your correctly free of charge. Its Pay It Forward time, and the least I can do to help you out.

Benz-O-Rama

You're A good seed.

MBH motorsports

I can get you my pricing from the dealer on a new piston. Just an option and putting it out there.

KLR CLS

Good peeps in this thread. Salik is a good guy, and deserves some help. Good luck buddy.

Pete

Yacht Master

Take a close look at #8 while you have her down.
Best of luck going forward.

benz_addict

Thanks guys for all your help! I really appreciate it & eurocharged is too kind. I'll take a look at #8 also..
Thanks Peter, remember I got a few SC bearings if you need em

mthis

ohh man sry to hear that, good luck with your rebuild.

if your looking for a motor you can pm bruce from ttm "TTMotorsports" i think he has a 55K motor laying around his shop.

stevebez

Ugh that hurts to see ... really sorry.

I would consider doing all the pistons after a tear down like that... u/stand cost is always a consideration but seems if one piston has gone reasonable to assume one or two more might be on their way...and would not want to tear the motor up again.

I would also go for forged replacements... I just dont know where you can get a set that is a direct swap.

sales@eurocharged.com

If the forged piston option doesn't pan out, I have a few stock pistons you can have free of charge.

Quadcammer

i would absolutely take that motor out and go over everything.

If you're this far along, no reason not to refresh all the bearings, and look at the other pistons for wear/damage.

Also, I really don't trust honing the cylinder with the engine in the car.

slownrusty

Can you post the compression results? Also did you do a leak down? Personally, I am not a big fan of replacing just one piston on any engine, especially an engine that suffered detonation or over-heating. A little extra effort in replacing crank bearings and a physical inspection of all the pistons (and rings) will go a long way for engine longevity. By the way, JE will make any custom forged piston for about $200-$250US per slug...I recently went through this with another project car I have.

Sorry to hear about the tragedy, but you have the right spirit and I wish you the best getting your CL back up and running soon.
Yasin

Exotic-metal55

I have several low mileage pistons.. PM, and let me know..

TheVazha

How many did you clock in before you noticed the vibration?