kjlindgr

Long story short, I pulled the motor out of the E55 a little bit ago and started tearing it down. Reason for the motor pull was that compression was low and it was burning oil...so much oil it would foul out the plugs. I've only had the car for the last 4K miles so I can't speak to any previous use, maintenance, or abuse. I was hoping for stuck rings and a quick turnaround on the rebuild. I'm not that lucky.

I read on here that some of the 2003's had ring landing issues with the pistons which was kinda one of those "first model year" issues that was later worked out. When I pulled the pistons, they had obvious signs of detonation...which will kill just about any piston.

Here are my main questions...does anyone know what causes this detonation in an all stock motor? Is the detonation due to something else in the motor or is it all just piston related and was "fixed" in the +2004 models? Was the design of the pistons changed in the +2004 models or just the materials? Any other combustion chamber design changes to prevent any hot-spotting?

I'm surprised that the knock sensors didn't trigger the ECU to pull timing to save the engine if it was knocking that bad...but so much for hope.




For those wondering what I found, here are 2 pistons. Both experienced cracked rings and/or broken ring landings. I haven't pulled the rest yet but a couple others look like they were detonating as well so I'm sure at least one more will look similar:

jkintegra

I just picked this car up, but at 50,XXX miles and w/prior owner the landings failed on the 8 cylinder.

Thank god it was under extended warranty.

They replaced with a brand new fully loaded crankcase from AMG.
$26k later, car runs strong, thank god for the warranty.

Didn't give any reasons for this. Just stated that landings failed.

I was not sure if this was a random or common problem on 2003 models.

Just hope now with the new crankcase put in June of 09, that it holds up for the long haul. Came with 1yr warr. from MB.

Sorry about the luck.

CharlyE500

$26K to fix ? ??

Yuille36

How do the heads look? After losing all that metal, off of the piston, those pieces had to go somewhere? This looks expensive, I hope that you have a warranty?

jkintegra

14k for crankcase
another 12k for other parts, ton of seals, redoing the crank, and labor, etc....
That does not count the couple grand the borrower came out of pocket for various items that warranty did not cover.
Think it was close to $30k almost.

Heads usually hold up in this type of thing.
Mine were fine. just needed to be machined as they were being put on a perfectly new block.
Now there should be higher compression though

You figure once you blow the rings, not much compression happening where the valves and heads are so they should not be messed up too bad if at all.

I would also think those pieces would not make it into the pressurized combustion chamber, but rather fall below the piston??????????

I would definitely recommend the head work though if you were to tear down the engine anyways.

SterlingE55

What do the top of the pistons look like? Pics please.

Yacht Master

Too bad, sorry to hear about your pistons. I was torn reading your valve stem reseal thread, cause I thought you may have happened upon a cylinder or two that would leak down, audibly. Well hope your block is OK, pistons & rings are available separately now.

kjlindgr

I'll post some pictures of the piston tops when I get home. The block isn't looking like it'll make it through this ordeal. I'm kinda bummed about this whole thing but I'll get my game plan together soon and evaluate the options.


EDIT: The heads appear to be fine. All the chunks of ring landing weren't actually missing when I removed the piston. They were still trapped between the rings...just not attached to the piston any longer.

EDIT #2: Yacht Master, I thought that I noticed a little louder blow-by on these cylinders than some of the others, but the tool I was using wasn't a true leak-down (no gauge, just a pressure fitting) and I was taking the optimistic approach hoping the motor hadn't shredded itself.

Max.H

That's what I don't understand. Even if the previous owner was running a low grade fuel and romping on the car in 100 degree weather. There is a chain of events that should occur. Knock detection, retard timing, if iat continue to shoot up, supercharger shuts off preventing further damage. This needs further investigation. I hope you get it all sorted out. BTW it's good to see someone willing to work on there own cars.


Looks like the ring land just collapsed? Ive seen severe detonation occur and it will actually start melting through the top of the piston on a corner. Then eventually destroying the rings. The top of your pistons "look" OK in the pics. Are you certain it was detonation and not inferior ring lands in certain 2003 models?

kjlindgr

Some of the pistons look like they were beat on the top with a hammer. This is usually a telltale sign of detonation...or some foreign material trapped inside the cylinder. Remarkably, the one I pictured above missing the ring landings has a pretty good looking dome. This picture is of the second one I posted with the chunk of ring missing and stuck in the side:




Anyone know if Mercedes has a transferable extended drivetrain warranty on these cars? Maybe I'm covered.

shockra

Tough break. I hope it all get resolved whatever direction you go.

SterlingE55

IMO all those nicks are from the piston rings or parts of the piston that came off. I see very little detonation which usually shows to be the worst on the exhaust side. So on the plus side least you don't have a bad tune or knock sensor, just jacked up cylinder bores and pistons.... I feel for you and hope it all works out for the best. Might as well port the heads and throw some cams in during the rebuild.

£ C43 £ AMG £

You should not have to go through this, I feel your pain.

weak design fault in the engine or weak fuel being used ?

I only use 99octane shell OPTIMAX and mine is an 2003 with nearly 100,000 miles

blackbenzz

Hmmm that sucks. Wonder what caused it.

lowprofile

Wow! Sorry to hear of your misfortune. This E55 has been an uphill battle for you, but in the end you will have a better vehicle for it.
One thing I would check is the ring gap on the second ring for any signs that the ends butted together. Also, I agree with dirty that most of those marks look like debris knocking around.

Marcus Frost

kj,

Sorry to hear about your trouble. Unfortunately we know little to nothing about intra-model differences on these cars, aside from what is clearly visible on the exterior/etc. I think something you may want to consider is that the car was previously modified, and may have run a bad tune/pulley/whatever setup. Tunes have a knack for getting around factory-imposed safeguards, unfortunately.

-m

mdweiss

look at the bright side, rebuild it all with some good forged pistons and you will have a bullet proof bottom end. It is probably cheaper to have the block re-sleeved than to buy a new block. I would also do some mild head porting while i had it all pulled apart, but that's a preference thing.

£ C43 £ AMG £

I have seen detonation recently on a Supra 600hp and the pistons melted because of the wrong plugs being used, the plugs broke apart also during the process.

The top of the pistons here don't show much melting just severe ring damage.

kjlindgr

Any way to tell if this car has a tune? I really would want the ECU flashed back to stock if it does.

skratch77

Hey kjlindgr,Im so sorry to read about your car myfrend.I remember seeing you were changing the plugs and everything to get your beast running right.

Im asuming it was acting up before you started changing things and now you can see why,you mentioned about having the timing off at one point,do you think that would of done this?

or was it not running good at all before you swapped the plugs and moved the timing.You could have the dealer update the ecu,they might charge an hour labor tho.

kjlindgr

The rear plugs in these cylinders were caked heavy with oil deposits. The issue was present before...I think I was in denial of how bad it could have been.

Any way the stealership could update the ECU without the car? I'm assuming not...but the car isn't exactly mobile at the moment.

shardul

iTrader: (1)

Well this may answer your question. If you connect the car to STAR DAS you can look at the ecu reflash table. It will tell you how many times the ecu has been flashed. Now wheather it is a reflash at the dealership or third party it will be hard to tell.

shardul

iTrader: (1)

Check around in your area if they have a mobile mb mechanic, who has star. They can come to your location! Houston has a very reputable one.

Brian GT PRO

From what I see that is not detonation, that looks like debris that got bounced around in the chamber. Very odd, as there is no lean burns on that piston as well..To me it looks like a failed piston, actually looks like there was an oil control issue that happened first, and possibly by this uncontrolled condition, you might have had ring flutter, then a failure resulted..Man sux, good luck with your build. If you have to do it out of pocket, might be time to do some nice internals for big boost.

slownrusty

I disagree..pistons DO NOT just "fail" especially on a $100,000 car with a hand built engine...they fail as a result of detonation.

KJ I am sorry to read this and see these pictures. What is the next plan of action? If anyone can build a new and strong engine you would be the person, I vote on sending your ECU to Kleeman and let Corey take a look at the tune on it and give you feedback.
Yasin