It's all fun till someone loses a piston
 

Just yanked these out of an R56.

Good reason to think twice about over boosting on stock internals

https://www.northamericanmotoring.co.../DSC004571.jpg

https://www.northamericanmotoring.co.../DSC004561.jpg

Whoops. :wink:

damn! Should make a nice conversational paper weight!

Bummer.....What sorta numbers were they pushing before this happened ?

damn some massive carnage!

It was about 215 WHP and 20 psi.

wow, all things considered that seems pretty conservative numbers, certainly nothing CRAZY, for stock internals, unless I am way off base. . . maybe I need to lighten up on the far right pedal.:sad:

mis-shift?

Could be the Brazilian pre-07' engines were bit more bulletproof than the new French 4 bangers.....

Ouch.

That's a bad day. :no:

Which leads me to my question...I have a stock '07 MCS and was planning to get the Accessport before getting exhaust, CAI, etc. This something I should worry about? Sorry this is prolly a question that a noob would ask and I am a noob when it comes to Minis and turbocharged cars.

Mike,

Can you explain a bit? How was 215 causing that? If that’s the case, I’d better back way off mine...lol.

Mark

Ouch :no:

It's out of an '07 MCS with about 50k on it, FMIC and intake. It was tuned but I will not say how or by whom to avoid the inevitable lock out and to keep things on topic.

The HP level was not the killer. There are quite a few MCS's running fine so far at that power level. From the obvious failure of the piston and the relatively low wear on the engine, it can be safely assumed that boost was the culprit.

The main point of the post and what I have been trying to tell people is that there is no need for the 20+ psi maps when it only nets about 2-5 more HP and causes this. This is talking average PSI at WOT, not spikes.

The JCW handles a little more since it has lower C/R, but don't expect a lot from those pistons either.

Mike FYI your in the Cooper NON S forum maybe you can get this moved:thumbsup:

I've also seen this so if you need a matching piston to that one I've got it:lol:

Sweet, I'll be that much closer to an entire engine with 95% leakage :thumbsup:

It's exactly how mine broke! 52k....tuned for nearly 30k and about 10k on a JCW turbo.

http://a3.sphotos.ak.fbcdn.net/hphot..._4442327_n.jpg

FWIW...there is a variety of cars that have seen this failure. Stock boost levels and high boost.....high boost just speeds up the inevitable, I would not imply that high boost is the sole cause of it.

Did you guys happen to check the piston to cylinder wall clearance at all? I've heard this might be part of the problem...........:popcorn: and it also explains a lot as to why some of these motors devour oil....

Care to elaborate on this for a non techie? Mine has an oil addiction...

There are other inherent problems with the R56, but most would not cause this type of failure. This is text book pressure failure. With out any other signs of abnormal wear on the cylinder walls, the piston skirts, bearing ect there is no other real reason for this to happen, especially when the engine saw 8+ psi over it's intended design.

The design of the piston is not ideally suited for boost really. The diamond head shape makes the rotating assembly light but also leaves a large gap under the ring lands. The direct injection is the only reason it works with the C/R it runs and would most likely fail at 7-8 PSI with port injection. It serves it's intended purpose well enough with all things considered so it's not entirely junk, but it's certainly not as strong as conventional designs.

Given the high volume the R56 was produced I'm not shocked some have failed the same way at stock boost, so I see the validity in stating this may or may not have happens on it's own. I would just find it oddly coincidental it let go after a tune that increased it to 20 psi.

That’s scary since I’ve seen 23 psi on mine. Though I haven’t checked it, I think the tune I’m running now is even more (it may not be, it just makes a lot more power)

I gotta figure out what to do.. .because the other tune I have does run 23 (on spike)

Mark

If the cylinder is too much bigger then piston then the gaps in the rings will be increased beyond a tolerable spec. This has the potential to pull oil into the combustion chamber and burn it off. Excessive gap can cause other issues like blow by, lack of power, blue/black smoke from the exhaust, and noise from piston slap.

At what rate is yours losing oil?

This piston has not just failed from excess boost pressure, there are a number of factors here to the failure, there is lots of excess thermal stress to that failed piston, poor tier gas is terrible for creating high thermal shock loadings (detonation/pinking) this combined with increased boost (heat) plays a detrimental catastrophic failure as we all see here!

HEAT is a killer of all engines!

Mike can we please see more images, piston crown, under the piston crown, the gudgeon pin, etc etc, you know what I'm saying.

Here is another example. :lol: :lol: :lol:

http://i636.photobucket.com/albums/u...a/IMG_0162.jpg

Of course you know a certain highly known company tested all their 22+psi boost maps for the R56 S engine with great success:roll: They will never stop using their customers as guinea pigs. I know you're not pointing out them directly, but with all their advertising about "Stage 3" maps with this dangerous amounts of boost in an R56 S non-JCW car people need to be more informed about why this is a really stupid idea. The failure won't be immediate, but when it comes boy I hope you've worked a lot of over time!

Underachiever we can get 100%:lol: