Brian GT PRO

I disagree with you. I have been building motors for over 22 years, and I HAVE seen failure on motors costing FAR more than an AMG motor, however I will go on to say that without X-ray and complete analysis we're ALL just speculating, however there are no obvious signs of severe detonation that I feel would cause that. HOWEVER I have seen collapse like this from too much cylinder pressure and weak ringlands.

Marcus Frost

I agree with your speculation to an extent Brian, but as you've also stated it is speculation. I am somewhat hesitant to blame this simple piston failure, but the idea of too high cylinder pressure is consistent with what I was stating previously that could be as a result of nitrous and/or improper tune. I think this car was previously modified, and that the motor had been hurt prior to Karl purchasing it. It is difficult to reverse engineer a tune but it is possible. A dealer will likely have trouble doing so, it will probably involve a tuner taking a look at the maps.

Even though I don't like to think AMG could have put together a motor with a bad piston, just last week I saw a V12 come out of a 12,000 mile SL65 who lost a connecting rod, bone stock, on his way back from a road trip. Engine replacement on the 65, I've been told, runs from $70,000 to $80,000. The 65 was under CPO warranty.

-m

Brian GT PRO

Completely agreed.

The engine replacement on the 65, is bone chilling for most that do not have the ability to build a new motor or have warranty to replace or repair. brrrr..

Marcus Frost

The 65 actually had a hole out the block, and from what I am told *unlike the 55s) the 65 V12 cannot be pieced separately. You have to buy the entire block + rotating assembly. I have not tried to verify this, though.

-m

blackbenzz

At that point I'd be looking at a used 65 engine or a whole car for that price.

£ C43 £ AMG £

kjlindgr

Have you been able to pinpoint the cause of the problem which would have prevented this from happening, your mileage was just over 50k which is low. Looking at your experiences I wont compare lists apart from when the rear end of my car fell off and I was in shock! We purchased at the same time and mine has nearly double the mileage and without a warranty. I find this all very interesting and I sincerely do not envy your current situation. Unfortunately only facts will aid you, so apologies for only theory ideas that I am mentioning.........

e.g. if previous owners of your car just turned the key and gave it WOT from cold every time (I am a completely **** and treat the 55 like my previous turbo charged cars with a proper warm up and cool down period)............or poor OCT fuel being used etc.

Are the landings the weak component in the chain of events, landings get damaged by detonation without the top of the pistons showing any signs of detonation? The top of the piston seems to have a fair bit of carbon build up which does not help combustion in the long run. The recent vacuum leak I had was not easy to highlight with no CEL showing and the car was running fine under load, but I assumed this would = a lean mixture?

Some have mentioned the over filling of oil in the past due to inaccurate oil sensors, if the crankcase had been pressurising I suppose it would have had blown oil out of other areas (have you checked the crank bearings yet to show signs of stress)

kjlindgr

Sadly, I don't have a root cause yet which is more than a bit disturbing. I hate to put work into this without knowing what the issue was...but sadly I need to get the ball rolling and address the rotating assembly. Before it gets fired up, I'm going to do all I can to get the ECU checked to make sure there was no tune on it. I've only had the car for 4K miles and don't beat on my cars. A spirited run here and there are one thing, but the car has never even seen WOT while I had it.

Here's another piston picture. This is of a different one that had all the rings and landings in tact so I'm not speculating foreign materials, but I'm definitely no expert either. I've got a few others with markings like this on the top. Any ideas?






EDIT: £ C43 £ AMG £, I saw your subframe woes and I'm prayng that nothing like that happens. I'm going to be paranoid from here on out I think.

kjlindgr

On a side note, I'm off to the machine shop tomorrow to see about the likelihood of getting this fixed is. They do nikasil plating as well so hopefully this won't freak them out too much:


Top and bottom shots of cylinder #7:

daniel3ooo

man I hope everything gets fixed! Best of luck to you!

kjlindgr

I did take a peek at them in more detail today. One of them stuck out as it was down in one spot through to the copper lining. I'm not sure what to think on that just yet. Otherwise, they looked pretty clean. I've got one connecting rod bearing that looks like it saw a chunk of something to at one time. Luckily, the crank looks perfect.

SterlingE55

IME your cylinder bores are in good enough shape for nikasil replating. I've seen some shops repair cylinder bores much worse than that. Best of luck.

MRAMG1

I was thinking the same thing. Those walls do not look that bad at all for having blown out ring lands, IMHO. I too have see, and fixed worse. But, it was without the nickel finish. Best of luck to you OP in getting her fixed.

By the way, from your other pictures of the pistons, something was DEFIANTLY making contact. Detonation does NOT leave indentations like that.

Ohbev

Are the stock e55 engines bores coated?

kjlindgr

They supposedly have Alusil sleeves cast into the block. So I've been told.

Anyone know where the foreign materials would have come from on some of those cylinders? Some of the pistons look fine...rings all in tact and ring landings all in place...but they have dents in the top like something was pounding around in there. It can't really come from the intake since the liquid/air cooler fins pretty much would strain out any bigger chunks assuming something slipped past the air filters.

I'm still trying to dig into how to prevent all of this again.

MRAMG1

IF, and I do say IF, the supercharger grenaded on him. That could have thrown a lot of debris everywhere. And YES some would have made its way throw the intercooler. Note, this is a BIG if, as I have only seen one that this happened to, and it was because of foreign matter in the intake.

kjlindgr

Let's hope that's not the case. It still makes boost, doesn't sound goofy or anything, and the screws still look to be all in tact. There are some minor rub marks in a couple spots, but nothing like chunks missing or anything from what I can tell.

Marcus Frost

That is exactly what I was going to suggest. It may have been from the blower. We had a member on here lose a large piece of a blade but it got wedged before it was able to make it to the motor. In your case, it could have broken apart and done a nice song and dance with your pistons, it appears.

Did you notice anything in your exhaust piping/catalytic converters when you removed them to do the long tubes?

-m

lowprofile

It is quite possible as we have a bypass valve which not only bypasses the s/c but the i/c as well. If the affected cylinders are all on the same side then I would suspect that a piece of debris hung the intake valve open long enough to push more debris into the surge tank.
What still puzzles me is that one pic of an intact piston with the second ring(scraper) missing a chunk. The only way I can see that happening is if the ring ends butted from thermal expansion. Either too much heat or the gap was too tight to begin with.

Zod

Check your Y pipe, there should be 2 metel rings on each side. these can slip out and get sucked into the TB and well....horible damages.

as it wa also noted check your SC to see all is well with it and no chunks are missing/ damaged on it

gl

kjlindgr

Why the hell would MB put some metal rings in there that get loose and suck into the supercharger? I'll so some searching to make sure everything is accounted for.


Marcus, no parts came trickling out of the exhaust that I remember.

Zod

On the Y pipe there should be a hard section on both left & right sides of the Y pipe. They are there I believe to kind of stabilise the structure of the Y pipe. (Not sure if it’s just 1 or 2 rings….)

Incorrect installation or handling of the Y pipe can disjoint/ loosen the ring and well if it gets loose and sucked through throttle body you know the rest

I do know of a few cars that have faced damages from Y pipe/ TB issues.
One had a clip form the Y pipe section sucked in…

There is also the possibility the car was run with no filters once and just sucked something in

Lastly, search for Jackpro. He had his SC lose a chunk from its rotary blades

Best of luck man I know how bad it feels when something in the car you love goes wrong

kjlindgr

Is there any way to fully inspect the surfaces of each screw? I'd like to look things over as well to see if that's a possibility but I'm not sure if it's possible to see everything without cracking the case open...which I don't wanna do.

blackbenzz

There is 1 ring in each accordian hose (2 total). The purpose is to prevent the hose form collapsing on itself from the vacuum when the engine is under boost. Why MB didnt have the rings molded INTO the hose I don't know. Bad design

£ C43 £ AMG £

Sorry to say it and I know it would be a PITA of an extra job,

but with what you have found so far........ don't you want to be 101% sure that if something (metal) did get into the piston chambers from upstream that there are no left over pieces anywhere? I would feel more comfortable if I traced all components in the chain back to the TB an air boxes.

If you find that one of the two rings is missing from the rubber inlet Y pipe, then you would really want piece of mind that nothing rebounded back into the supercharger case and the same for anything else that may be still lodge inside also.

I checked the rings in case they had become dislodged after doing the valves cover seals reading some of the threads a while back. Fingers crossed they have never been a problem, I dont think its that common as I have taken my air boxes/Y pipe off so many times now I have lost count.

Best of luck man.......... I admire your tested patience

£ C43 £ AMG £

Do we have any other options with these rings?
replace them for plastic a equivalent?
replace the Y pipe with a samco type setup?