Call back Mini USA and ask to talk to a supervisor, they are trained to say that kind of crap. Get the next customer service reps name that says that to you and put in a complaint against them as well as the other one you talked to if you remember their name. The starts and ends with me BS doesn't hold water in 99% of the cases. You should have documented each time you called with the date, time, customer service reps name and a write up of what was talked about. A lot of places record ALL there calls (that's why you are told that at the beginning of the call). I think the dealer needs to prove to you they didn't cause the damage.

 

Couldn't detonation damage the spark plug?

The knock sensors are supposed to tell the ECU to make the plug not fire if it detects detonation, but what if you had excessive detonation that even the knock sensors can't deal with? Like if the carbon deposits caused two or more hot spots that ignited the fuel way, way early? Or if you somehow bought gas with such low octane that it detonated as soon as you looked at it? Or what if the knock senors failed? Or the ECU failed to correctly respond to detonation?

Just wondering. Also, what is the theory for what caused all the carbon buildup?

I realize that the "bad gas theory" is the dealer's favorite one-size-fits-all explanation for anything they can't explain, but you know a stopped clock is right twice a day...

 

How old is your nephew who was driving the car? How well do you know him? What was the road like where the failure occurred?

I don't mean to accuse, but would you have any reason to suspect he might have been abusing the car? Has the dealer given you the readout of the car's computer (which I believe would record if the engine has been overrevved)?

Stuff like this seldom "just happens". Someone screwed up - driver, mechanic, spark plug mfg, etc. - although given the number of variables and players, Columbo might not be able to get to the bottom of this one.

- Mark

 

I don't think this has anything to do with mini usa. It is the dealer, or whoever took out the sparkplug to clean the cylinder with walnuts that is on the hook. They were just in the area doing work, the damage is uncommon and very easily be connected to the last guy who touched the spark plug.
I can't help but think you are just getting taken to the cleaners.

If you insist and find out exactly what was done to clean carbon, I think you will find that they just played with the plug a couple weeks ago. It is just too much of a coincidence that after this work you have catastrophic failure. If they are not the cause, I would make them prove it to me.

 

I simply can't believe the sparkplugs were not replaced when the carbon was cleaned! How could any mechanic make such a error in judgement at ~50K miles AND while cleaning everything else in the camber. It's a sad state of afairs indeed... Best of luck!

One quick question:
When the timing chain repairs were made did they replace ALL parts including: the chain, tensioner, gears, etc... ?

There's a post about that and all the part numbers are listed. They should ALL appear on your receipt for that repair.

 

Due to Saturn going out of business, I had to have my warranty work done at a Chevy store. I will tell you that while I was sitting in the service managers office talking to them about MY car, the Chevrolet field rep stopped by. The service manager grabbed the rep to talk to him about a Corvette they were working on and I was sitting there for the whole conversation. The Corvette was 5 months out of warranty (they have 5 year/100,000 mile powertrain). It had just over 40,000 miles on it and had dropped a valve in the motor. The service manager asked the field rep if he would consider some "good will" help with the car. They left to go look at the car while I waited. When service manager came back I asked how it went, and he told me Chevrolet was going to cover 90% of the repair cost, customer 10%. The rep told him this should not have happened, car was stock and well cared for. My best friends daughter lost the transmission in her Cavalier just out of warranty, and GM helped them also (I do not know the details of how much).

I am here because my wife desparately wants a MINI, and I am trying to learn what to look out for before buying one for her. We dumped her Hyundai Sonata because I got tired of Hyundai threatening to void our warranty every time we took the car in for something (which was ALL THE TIME). I am terribly sorry to read of the OP problems.

 

Contact euro techs for a second opinion. Eurotechsaz.com. 480-656-0341. Jerry the owner is a very honest guy and used to work at mini north Scottsdale and now opened his own shop. Everyone in our local club uses and speaks very highly of him.

 

Unless you plan to lease a Mini and turn it back before the warranty expired or buy an extended 100K warranty and even with that if you missed a scheduled maintenance they will void your extended warranty or you will comfortable with the possibility of $12,000 quoted out warranty repair with my car water pump, carbon build up in the valves, stretched timing chain and now broken spark plug damaged the head with only 59,000 miles and 3 years of service. DON'T DO IT, also I've heard once your car is out of warranty Mini dealer will give 40% below wholesale values for trade in and they know how expensive and what kind potential problem they could have.

 

whats the latest on this?

 

I would steer clear of MINI unless you plan on keeping it until its out of warranty then trading or selling it or buying that extended warranty. These little cars have way to many very expensive issues that crop up.

 

I'd get a MINI if you want a cheap, reliable, fun car that will last.

 

I would really like to know exactly how this walnut blasting is done without filling up a cylinder with shells . Unless care is taken to make sure all valves are closed (may be impossible on all simultaneously) then this is asking for trouble. Fact is walnut shells are quite hard enough to break a spark plug so I would be looking at this as the most likely cause.

 

From what I've read, the reason they use walnut shells is in case a small bit of one did find its way in, it will just burn off instead of causing any damage.

 

Finally got all 4 spark plugs back from Scottsdale Mini after they replaced my engine. Went to Ontario Mini and shown the spark plugs to the service manager and was told the broken spark plug ground electrode was due timing jumped caused the piston to smashed into the spark plug and they’re not responsible for the cause of my blown engine. Even though the broken spark plug shown no signs of being mashed or any damaged to the positive electrode and the break was very clean as shown in the photos. Can someone explain to me how can the piston come into contact with the spark plug and caused it to break?

 

That's up to them to explain. I don't see how it could happen, as the spark plugs do not move within the combustion chamber. They're always in the same place, so if the pistons could ever hit them in their regular travel they would hit the plugs every single time.

So it sounds like they're feeding you a big ration of BS to get out of having to pay for the engine work.

 

Two very remote (and I'm not even sure they are 100% possibile) possibilities: crank bearing (which could explain the timing jump) or piston rod (and/or rod bearing) are shot. Over-revving when downshifting can damage the rods. It's not inconceivable that it could also be related to the timing issue too. If there was actual contact between piston and plug, there will be a mark on the piston.

Otherwise foreign debris inside the cylinder hit it. If so, it's probably still in there. Have a look with a scope. Like I said before, if the engine was over-revved, this could be related to valve damage that shed debris into the cylinder. This may have struck the plug.

Could also be due to detonation resulting in a bent plug or an incorrectly fitted plug.

In any case, your entire sequence of events is strange. When you say:

"Drive the for few days and it ran fine and last Sunday my nephew drive it from Chino to Arizona and noticed the check engine light came on"

This is not how a plug would catastrophically fail. You'd hear it and feel it, it wouldn't be a simple CEL light coming on. Furthermore, were there debris in there after the walnut blast the problem would have occurred when you initially picked up the car after the walnut cleaning. It certainly wouldn't have "run fine for a few days".

You probably won't like what I have to say and I understand you're upset, but realistically I don't see how this is the garage's problem. According to you, the car was fine until your nephew got into it. If I were you, I'd be talking to your nephew and checking whether or not the ECU registered a redline.

 

A little search I did turned up three possibilities for a piston hitting the spark plug. One, bad rod let the piston travel farther than it should have. Seems unlikely. Two, if the spark plugs were installed incorrectly, they may have been set deeper than was proper resulting in them hitting the piston. I believe earlier in the thread you indicated they had taken plugs out when doing some other work, so this seems like a possibility. Three, if the timing is off causing improper detonation, it may be possible the detonation was strong enough to damage the plug without an actual strike with the piston occurring. Would have to look at the actual piston head for evidence of contact. This sounds like the reason (sort of) you got from the SA in blaming it on the timing jump.

 

Don't understand your theory #2, spark plugs installed incorrectly, set too deep. How can you install a plug too deep? You screw it down on a seat, and torque it. The plug can only go in to the point the where the plug seat meets the head seat. The only way to get a plug deeper into a combustion chamber is to install a longer (wrong) plug and the piston would hit that plug as soon as you start the engine not magically a few days later.

 

This is a common technique, not just for BMW/MINI, but since we are on that brand, yes, BMW/MINI does use walnut shell blasting to clear carbon build up. Its a specific machine they have for doing the procedure.

Also, someone mentioned they don't know why/or it should be discovered why there is carbon build up in the first place... I'd suggest reading through threads on NAM and doing a general search on the web for direct injection engines (which is what the R56 has). Carbon build up is a huge issue in our cars, and MINI knows it. Without port injection, the intake valves, manifold, TB all get built up with carbon from oil blow by within the system. While this is nothing new for cars, the difference in DI engines is fuel is injected directly into the combustion chamber, thus not allowing for the gas to clean your intake valves etc of carbon.

As for the OP, I'm surprised you just jumped and had them change the engine without much hesitation. I would have kept fighting until they came up with a resolution that favored myself... mostly because it had been in there for work dealing with related components only a few weeks before. They never told you that over-revving was recorded, as that'd be an easy culprit to blame on if they saw it. If they say timing jumped.... then why would it have jumped? Didn't they just replace the timing chain/tensioner?? Is that not directly related to timing? I'd be digging deeper if I were you and not gone ahead with the fix so soon... Thats a large chunk of change.. =\

 

I'm not real sure. The various threads I've found usually indicated it would be something like the plug got cross-threaded which then allowed it to extend further into the cylinder. I would think that would be a pretty easy thing to see though once you pulled the plug (much less feel when installing the plug). And like you, I would think if that were the case, the strike would occur the very first time the engine started up.

 

If the plugs are the correct parts for the car then cross threading will not result in seating the plugs any deeper into the cylinder than proper threading and would most likely result in the spark plug being unable to completely seat as designed. Typically anything that you cross thread is started slight askew and "seems" to fit at first but suddenly becomes very difficult to tighten all the way.

 

i would take ontario mini to small claims court. they seem to be the at fault....

 

IMHO the well documented known timing chain issue is the core cause... (best guess on my part having not inspected the engine)

Didn't look back over this thread, but did the valves hit the pistons?

I've only had one engine "blow up" on me over the years. It was a racing Honda SL70 set up for TT and Scrambles. Had domed pistons, big valves, massive cam and very tight tolerences. This thing was pushed to the limits; running nitro-alcohol blend.

Slaped a license plate on it one day after school as a teenager and headed to Saddleback Park in Orange County, CA for some track time. On the way home I ended up racing a Honda 750 down Champman hill. Yes, a 70cc racing a 750cc. Was in the lead until it exploded!!!

I over rev'd it and put the valves through the piston. One valve broke off and was fused into the piston dome. Oops!

Funny memory now, but not at the time. Almost went down hard on the pavement when it blew...

ADDED: Hey Satang, did you ever get a report from the "black box" CPU telling you what was happening at the time it went?

 

The engine was never over rev and the all four plugs are oem and only time they're taking out was during the carbon blasting. As you can see the spark plug shown lots of deposit on them and the broken plug shown no signs being hit by the piston.

 

Wow that is very much coated with carbon. Everything you keep telling us points towards the dealers fault. Maybe the tech dropped the plug on the tip which weakened it enough that a few heat cycles made it fail. ...micro fractures/cracking leading to liberations are seen by this.