Pic 3 is the blower just as it was removed. Full of engine oil and metal parts. Lot of engine oil in intake tubes, bellows and intercooler.

Did the metal go up hill and ruin the SC or did the ,metal go down-hill and ruin the block?

The drivers side bank of pistons, head and valves , seem to be in better shape. There is some some metal but nothing embeded in piston tops or wall scoring, like on passenger side.

my version..
cyl 8 had detonation -> threw the rod and melted the piston -> piston tapped the valves possibly

oil came up from the cyl where piston used to be into the blower.

not a pretty sight.

found myself looking at a similar picture several years ago in my honda.

i'm thinking the bottom half gave first, caused oil to get thrown back up into the blower and intake, then with the blower trying to do the impossible (compress a liquid) it also gave out and began to eat itself.

Here are a few more shots..

Bent rod was still connected to crank but piston was gone. Only the wrist pin left on the end.
Engine showed signs of sudden blow by (smoke coming out oil cap, etc. etc. , before piston broke and busted out side of block.

All that oil in the intercooler and SC is a sign of over pressure in the crankcase that sent lots of oil up the vent located on the intake just before the TB. I'll bet the TB is also full of oil?

When that piston/valve went, supercharger pressure all went into the crank case. Metal parts flying around did all that scoring damage.

Was there large metal in the SC screws ??? I'd be surprised. How would it get past the intercooler? (Except for maybe tiny bits getting sent up with oil in the vent.)

I think #8 piston cracked and a part of it held the EX valve open till it was hammered by the piston then the valve cracked off and proceeded to knock its way through the top (or side) of the piston producing more metal flake than a bass boat has. Once the piston gave way the EX pressure and the crankcase breather vacuum fed metal flake oil to the SC and other cylinders. Shortly after that, what was left of piston #8 checked out and let the rod find a nice (non top guided) spot to exit the block.

Yes , there was oil in the TB. Here are some shots of the Intercooler on the by pass side and SC pressure side. There was a lot more metal on both sides but these parts have been moved all over the place.

The valve and piston parts , are what were stuck in the hole in the side of the block.

So, are you saying all the metal and oil went up the intake side (through intake valves and up the by pass) and into the SC? I see a lot of ground up parts but not melted, light colored or burned. The SC rotors , really do not have that much damage, once cleaned. Teflon coating is gone, few chips and scratches but way to much ground metal to just come off the SC.

i'm gonna have nightmares after these pics...

Putting it mildly.... OUCH!

Given the information presented I personally would be lead to believe this is the result of a stuck valve from valve breakage. I am thinking that the exh valve head broke off, stuck under compression, cause the cylinder to become over pressurized, destroyed the piston, bent the rod, and bounced the head of the valve around like no one's business. This obviously happened under boost and I agree that the signs of crankcase over pressurization are fairly obvious. A stuck exhaust valve could instantly bend a rod and put it out the side of the block, especially under boost. A cracked piston can lead to compression loss and therefore would be less likely to bend a rod but there are ways of that happening as well.

The fact that a lot of metal went back up the intake tract also would have one believe the exhaust valve stood closed for some time and forced everything back out the intake side up into the TB/SC/intercooler etc.

Just a theory though. Exotic can you please tell us what modifications were done to the car at the time of failure, and also what were the driving conditions?

-m

Safe to say they aint gonna be able to fix that one. Dayam like seeing seals being clubbed - I won't be the same again after that gruesome episode.

I am with the bust/stuck valve crowd... over pressure, rod / piston, casing overpressure and it was blender time - thats all she wrote.

Btw was the crank bent at all, not that it matters just curious?

And also would like to know the mods / circumstances of the failure?

Yes, motor was at WOT on a series of WOT test. It was a like a minus 2000 DA that day. Boost was the best it could get.. Stuck valve? Only had 39k on the motor. Anything else I can take pistures of or show everyone to help the diagnosis.

Could this theory be possible? SC rotors chip and metal goes out the by pass, sticks in exahust valve breaking it and then crushing piston?

My mods are in my signature , excluding the Forged pistons. Just the basic stuff, Good sea level air and good tires..

Ported heads, cams, headers and custom torque converter was in the plans ,, until I had to use a year of my kids college fund for the motor..

That is a good one.. I was thinking more like being split and quarterd,, like Mel Gibson in the end of Braveheart.

I am actually going to take this block over to a top motor builder and see about Siamese steel sleeves. Oh yeah, weld the hole up too.. Cylinders are only like 5.25 deep,so stroke may have to stay around 3.8 max but hope for a 4" bore. Then just put low cost domestic race stuff in it. The new rings out for 09 are down to 1.2mm on the domestic side and that is in line with our quality now.

Could the custom forged pistons have contributed to the problem. I don't think it is likely, but could the piston to valve clearance have been off on that cylinder? Unlikely but that could explain the valve breaking at the stem.

Sorry for any confusion but ALL internals of the above motor pictures are stock. Just the way , the one man one motor built it at AMG.


I have custom Wiseco`s now and Nikasil coated bore.

What a horrible sight... Poor motor.

Depends what the rod bearings on the bad cylinder look like? If it was starting to throw a rod bearing that will begin a vicious cycle... Improper piston to valve clearance, causing piston to valve contact, bending and ultimately breaking the valve off then... Kaboom.

Exhaust valve head broke off.

This is the third motor I have seen this happen to.

Supposedly only on 03s.

total loss.. Maybe an over revved motor on a questionable tune lead to this.

WO0OW

really shocking

did it take time to happen ?

or just suddenly you felt something or heard and then Bo0om ?

I don't have a good explanation for the chips in the end of the super charger rotor but that is not what caused the failure of the engine.

How long did it take for the engine to "spin down" after it blew up or did it continue to run?

I have seen a lot of catastrophic failures but this one really scattered a lot of metal everywhere.

I am probably pointing out the obvious to you but I wouldn't even remotely consider reusing the intercooler core as you will never get all the metal shavings out of it.

I checked the beartings on that Rod and looked the journal. all the bearings in the whole motor are in great shape. The Damaged rod , does have some copper showing on the edges but that has to be from the rod not having the piston guid it , after it broke off. Top guided motors need the piston to guide the rod, or it will float around on the crank.

The Rev Limiter was set at the stock RPM .

A/f Ratios were in the 11-12 range.

I was never sure but I thought I heard a "tinking" sound near the top of a WOT run but was never sure. I still hear the sound today in my head. The next WOT run and then I noticed the blow by but car was still running good and strong. Two more runs and that was it.

After two hard runs, the car had blow- by coming out the oil filler tube and maybe PCV hose. I do not belive the valve just broke but that something caused it to break. Metal had to be getting in the motor/intake for the blow- by to start. I would assume, that one chunk of metal getting caught in the Exh. valve, as it was closing could snap it off.

I Knew something was wrong but must have been in denial. Made another WOT run and lost power, oil everywhere and that was it. I would say it was very quiet when the motor broke. I was suprised how quiet it was..

Exotic,

Has the cylinder head/valve train ever been touched on the car? A valve doesn't always break instantaneously, depending on a number of factors that could cause it to break.

-m

Marcus, to the best of my knowledge, the valve covers were never opened. I ran checks on the previous owner and it checked out "as owned by a little old lady in Texas story". I used a magnifing glass to check bolt heads all over the car and could not find anything that made me think it had any major work.

Something broke or started to break on two WOT runs before, causing the blow-by smoke to come out of all the under-hood orifices. One more wot and it went..

If there was blow-by,, wouldn`t a piston be cracked already? Maybe even several pitted intake valves, as the motor was coming apart? I am not an expert , but would assume the exh. valve would not be attributed to the blow-by.

How come others on this forum do not post about blown motors? I hear Vadim say he has seen 3 just with valve issues. Other people make small quick remarks but no INFO to learn from.. Even the 04 E55 motor I bought , had been blown before. At first, I thought i was a freak of nature but now this seems to be common..

Interesting to know..................I have an S55 motor that looks exactly like that one sitting in the shop(I work at) right now. I can't remember the year of the car/motor off hand since it was one of my bosses many cars and the engine was replaced with a complete($6,000) used motor/blower about 8 months ago. If I remember I'll check on it Monday.