Hey guys. I'm starting to get overwhelmed. I have a 2003 cooper S. I bought it in December of 2014. In September of 2015 I blew the motor. A few weeks earlier I blew a plug. It just came straight up and stripped the seat. We went ahead and put in a time sert. Originally we thought the motor blew because there was something wrong with time sert we installed as it was in the same cylinder as the time sert was installed. I replaced it with a 05 used motor. About two weeks into motoring, this engine blew..... we removed the head and saw there was a time sert in the came cylinder where the piston cracked on this motor (same problem as the original motor), coincidence?...After several hours of phone calls and questions to anyone I could think of, it came down to an injector problem. The car has a few mods, and was never tuned with stock injectors. I'm rebuilding the motor with RMW one size up from stock pistons, rod bearings, and 450 injectors. I'm also looking into an oil pan baffle and obviously will be replacing gaskets.

My main question is, is there anything I'm missing and need to be replacing? Any thoughts, concerns, ideas, recommendations are much appreciated.

Mods: MSD coil pack, cooler plugs, KN Typhoon intake, ATI +2% dampener pulley, Alta 15% SC Pulley, Invidia Cat back exhaust


Thank you in advance.

EDIT: January 18, 2016
I picked up my block the weekend. It was cleaned, magnafluxed, decked, bored, and honed, and cleaned once again. I'm very excited to begin putting everything back together.
Also created an oil pan baffle. When I took the block apart the rod bearings showed oil starvation. Bill at Carlquist in CT told me this could be due to hard corning- all the oil flows to one side and the pump stops picking it up. Simple- two pieces with trap doors on each of them. You can find an oil pan with pieces welded in (without trap doors) and pay $399 +$200 core charge. Or buy a different kind of oil pan baffle for $175 from RMW. Instead, I made my own. Getting welded in tomorrow.

My MINI will be back on the road soon!

 

What caused the cracked piston? What type of fuel do you run? How much boost? Stock tune? Did detonation/pinging kill the piston?

You need to find out what caused the failure first...correct that, and then put together your new motor.

 

So has there been any other damage besides the spark plug holes stripping and piston cracking? Rings intact? Walls scored?

What plugs are you running and have you torqued them to spec?

A lack of fuel wouldn't cause those plugs to come out of the head, that is a notorious issue with improperly torqued plugs.

Were there any codes stored? Your car would have stored some sort of data had there been an issue with detonation or misfires, especially if it happened enough to cause damage.

 

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I believe detonation caused the cracked piston. Always preimum fuel. The car was never tuned.

 

A piece of the piston broke off and scored the wall. The plugs were torqued to spec two days before the second motor went. The codes were misfire in a cylinder. After the first motor blew, as well as after the second.

 

What size pulley are you running? Is this a track car, or a street car? Sounds like you need to have it tuned on a dyno after you get it going again to keep the detonation from causing damage to the new motor.

 

Which cylinder blew? Were the misfire codes always for the same cylinder? Also, check your fuel pump and fuel filter. Its probably going lean because the fuel pump is dieing or the filter is clogged. The mods you have listed shouldnt kill an engine, even without a tune.

 

It has a 15% reduction pulley. Street car but I don't baby it. I drive it hard. I plan to get it dynoed after the motor is in.

 

the factory internals are forged in an r53, these pistons just don't blow up. something has to cause this. Ussually a lean condition over time reheat treats the metal of the piston and wears down the metal until something lets go. (hot spot). Spitting out the plug is a coincidence, or something wrong on your part. as for blowing the motor, something is wrong with fuel delivery. if the rest of the pistons look fine, you can most likely say that its an injector. if all the pistons have hot spots, could be a fuel reg, pump, or filter.


a 15% pulley should not detonate a motor and if even using bad fuel there would be knock and codes thrown before. where as your ecu could have seen a leaner condition and adjusted the trim, run rich in 3 cylinders and still lean in one because of a bad injector and still think its fine.


spark plugs can tell enough of a story

 

On the first (original) motor cylinder 2 blew.- which is the same cylinder that has the time sert in the head. The piston cracked in on the outside of the piston itself and scored the wall heavily. I brought the block to be honed and bored. The machine shop started and found a hole in the wall so the cylinder is being sleeved. And then bored and honed one size up from stock for larger pistons. The codes read "misfire in cylinder 2".
I bought a used motor with 60k from an 05 with the supercharger. This head had a time sert in cylinder 3. After two weeks of driving the car, the motor blew. We pulled the head and the piston cracked the same way as the first one did. Wall was also scored. This block I still have in the garage. The code just read "misfire in a cylinder"- didn't specify which one.
The fuel filter was changed at 70K. I only use premium fuel and I use Lucas cylinder/ injector cleaner every so often.

 

I'm getting new injectors when the motor is done at the fuel shop. I forgot to mention the plug itself was burnt on cylinder 3 in the second motor. I never had an over heating issue with this motor.

 

Sounds like you have a bad injector.