Detonation issues = motor go boom-boom
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
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
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
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..
-m
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)
Last edited by £ C43 £ AMG £; Feb 22, 2010 at 07:25 PM.
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.
Top and bottom shots of cylinder #7:

The Best of Mercedes & AMG
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.
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.
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.
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.
Did you notice anything in your exhaust piping/catalytic converters when you removed them to do the long tubes?
-m
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.
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.
as it wa also noted check your SC to see all is well with it and no chunks are missing/ damaged on it
gl
I'll so some searching to make sure everything is accounted for.Marcus, no parts came trickling out of the exhaust that I remember.
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
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
replace them for plastic a equivalent?
replace the Y pipe with a samco type setup?









