I've read as this thread front to back and from what I can tell the shop is going to re build the motor but have no clue as to why it happened in the first place? Have they given you any of there thoughts as to the root cause of the failure

Randy,
The shop's theory is that the ceramic pieces that came off the spark plugs went into the chamber and caused the valve to break/fail , but we already know that this is not the case as the valve actually melted.

Unfortunately, I cannot take the car to a different shop becuase the bill would be picked up by the extended warranty.

Thanks for posting.

Hernan

 

I do understand that you are more or less locked in there . At the very least get in writing from them a guarantee that if the same issue happens again you have some recourse. Even if you use their reasoning spark plugs just don't melt on their own . Something caused the heat and if they don't find the reason you all will be going through this again shortly . Good luck and keep the updates coming as you do have a lot of experienced members looking on which could offer some further assistance.
A quick additional thought for you to ponder . It is my GUESS that it is not the injectors. I feel it is rare enough for one to go bad but to have two have issues at about the same time really increases the odds against that being the problem. Perhaps some of the engine pros could chime in on the frequency of Bad injectors from BMW ? BTW what mileage do you have on the car and how many approximately on that set of spark plugs as well.

Randy
M7 Tuning

 

two going bad at once, really failing wouldn't be a high probability event. But if crap got into the fuel lines, then having more than one choked off and running lean is possible.

Really though, it's relatively cheap to get them tested and cleaned. I found a 3%+ degredation in flow with just one year on a set. Best case is that they're fine and you get improved flow patterns, a smoother idle from better atomization and you're out $60 or so. Worst case is that one or more are bad, and you have the chance to get them replaced under the warranty claim.

Matt

 

Sounds like this would kill two birds with one stone . Eliminate one variable at the very least and start you off with a fresh set of injectors as well. Sixty bucks well spent I would think .

Randy
M7 Tuning

 

Another good place for injector work is Marren Fuel Injection http://www.injector.com I've used them before and their turnaround time is very quick, 1-2 days. I'd bet they know a thing or two about MINI's fuel injectors too. Click on this http://www.injector.com/competition.php#section1

Tim Marren, Crew Chief RSR Motorsports. They race MINI's in Grand-Am Koni Challenge. I'd imagine he's in Daytona right now prepping the cars for this weekends race.

 

[quote=gnatster;2637219]Another good place for injector work is Marren Fuel Injection http://www.injector.com I've used them before and their turnaround time is very quick, 1-2 days. I'd bet they know a thing or two about MINI's fuel injectors too. Click on this http://www.injector.com/competition.php#section1

Nate,
I like what I saw on their web...saw a few minis .
I am going to have the injectors checked for sure.

Hernan

 

Cucho,There are still many things that may have caused your problem.
How old were the plugs?
Some softer metal fragments got sucked into the 2 cylinders.....

What ever the cause, we do know that something stuck ( combustion side )to 1 of the exhaust valves & burned a hole in it. The engine had to run long enough to create this failure. The question is, did the plug fail because of the heat caused by the valve burning or was it the plug that broke up with a fragment sticking to the valve?
The other cylinder could have been a similar failure, only the debris stuck to the edge of the valve ( non cumbustion side ) causing it to bend when it shut.
The pistons, based on the pics ( too hard to realy read ), don't look bad, not so bad that there would be any dammage to the bottom end of the engine.

Another question would be the the head gasket. If the "O" rings on the gasket failed & got sucked into the cylinder, the material ( "O" ring ) can burn at very high temp.

Like reading plugs, the pistons, the head gasket tells a story also.

 

I think most of you know I'm not really an engine guy. However, I didn't read anything about the photograph of the spark plug...it looks like all four electrodes are badly burned/melted...one looks like it is almost gone.

If the tune leaned the injectors while not considering the heat range of the spark plug(s), why not return to a stock A/F ratio, install new injectors and repair what is broken? I cannot imagine that the car performed very well thru the rpm range as such.

I have been told that the JCW install uses a very conservative A/F ratio...basically that it is a pig with regard to fuel use at higher rpms in an effort to cool the combustion chamber.

My JCW engine has 149,000 miles on it. I replaced the spark plugs a few times, coils and wires once. With other basic maintenance it runs great...the diet occasionally includes BG fuel injector cleaner - just before an oil change.

 

We're gonna miss you this weekend bro....

Hope the car comes back stronger than ever.

Alan

 

Meb, I think most agree with this assessment. I believe cucho is just eliminating all other possible causes of the problem. I don't speak for him at all, but I think he is going about it is at this time pretty wise.

 

Cucho, look at the top of the pistons in the failed cylinders. If the plugs were burning up ( too lean ) there will be a tell. You will see pitts from the cast off spray ( plugs ).
There should also be some fault codes. They may be of some help.
At this point, IMHO, there is not enough info. I've seen plenty of burned valves & holed pistons from too lean but never a hole in a valve.

 

[quote=stevecars60;2639271]Cucho, look at the top of the pistons in the failed cylinders. If the plugs were burning up ( too lean ) there will be a tell. You will see pitts from the cast off spray ( plugs ).
There should also be some fault codes.

First of all I run those plugs for about 5-8 K (relatively new).
Piston 1 & 4 look different. On 2 & 3 there was a little "gum" on top that was not present on 1 & 4.
As far as codes...yes I the same day the car had the catastrophic failure I got the codes you are talking about.

And yes, I am only trying to eliminate variables.

 

[quote=cucho;2639292]There are lots of variables.

The plugs are fine - 5-8k is good. They are designed for +20k.

The "gum" - is not what I'm refering to. It would be pitting from the hot metal ( spark plug ) burning pits into the top of the piston leaving some partical embedded in the top of the piston ( with enough material - it will burn through the piston ). The "gum" is an after effect of the failure ( unburned gas that has evaporated to the point of residue & what ever the non exhaust valve can collect on an intake stroke ). In most cases the pistons get holed, not the valve, also the valve would normaly burn off at the edge on the high presure side of the flow.


If you have the code numbers, please share.

 

[quote=stevecars60;2639367]No pits found on top of the pistons.

Regarding the code, unfortunately I do not remember the code # but I remember it was relating an ignition problem that is why somebody sugested to change the SP wires/cables, so I did and when I went for a test drive around the block ...plop. I was barely able to return going 20 miles an hour as I now running on 2 cyl only.

 

The pistons all look the same? No pits? This is a good sign.

There are, more than likely, more codes stored.

After the wires were changed, was there any difference? Just trying to establish a time line.

 

cucho, apologies if my question came off the wrong way. I was trying to learn some diagnostics pathways.

What about the coil? Could your tune have affected the coil and therefore the current to the plugs?

Good luck with this!

 

That would be a no. There would be no difference in the coil output regardless of the tune. However the ign timing could be changed with a tune.

As others have said on this thread, without seeing, it's difficult to determine the cause of this failure.

Looking at the valve, the way it burned, the shape of the burn would suggest that a piece of the plug stuck to the valve & somehow the ign fired right to that piece & burned the hole. That would mean that the combustion would take place at that exhaust valve, already hot & getting hotter with every combustion stroke.

 

After the wires were changed, was there any difference? Just trying to establish a time line.[/quote]

Ok, here it is the full story with time line...about two months ago I was at TWS running clockwise and spun out (no I wasnt' too HOT - I wasn't smooth - bad driving). So right after the spun the car went into "safe mode" and it started throwing the misfire codes you mention. Even though I cleared the codes they keept coming back including the DSC "off".

Track support's chief mechanic suggested to change the wires, so I went back to Houston. On my way back I could already feel the car lacking power, most likely running with only 3 cyl.
After replacing the wires car sounded like power came back...however when I went for the test drive the catastrophic failure occured...I was suddenly running with only 2 cyl. (cyls 1 and 4 were gone!).

 

Ahhh.... Racing, were you.....#1 I don't like those 4 prong style plugs. They work well in my Explorer but that's about it. You have 3 more things, per cylinder, that can fail.

At this point, IMHO, the plugs were severly stressed & failed. They did not burn up from a lean condition, injector failure or the tune. The spark arms became distressed from track time & broke, more like fell, off. There is no evidence that supports a lean condition - there would have been spray on the pistons & the spark arms would be rounded nubbs ( usually burnt pistons with melted top ring lands, a hole or both ). It is odd that the plug material did not stick to the piston.

Do you think you spun for loss of power? Bad driving or not, I think so....

I'll go out on a limb & say that there is no harm to the bottom end. I have a tripple fire suit that still fits... so any flamers.......

I'm not a dealer fan but I think their judgement, with this issue, has merit. I believe you'll be ok.

Still like to see all 4 plugs, the head gasket & a high res pic of the tops of the pistons.

 

Cucho,

Hmmm, probably should have brought this up right away.
Respectfully though I don't agree with my fellow new Englander above.
Tracking your mini will in no way stress out your plugs, unless of course you have an "on the edge" tune.

Your spin. Both feet in?? Haaa. It's possible that you reversed reved the motor and bent the valves then.
But, it's also possible that you were loosing the motor and it gave out on a turn and you spun. Only you know how it went. Did you notice any power loss during that run? Or was it strong right up to the spin? Did you stall the motor?

 

that things are far enough along that we'll never get a high confidence read of the ultimate source of the failures. That said, there are lots of things to do as the engine goes back together to make sure that the rebuild is as robust as possible.

With the codes gone, and the parts getting fixed as we write (I'm assuming), I'm guessing that lots of details will be lost to history....

Matt

 

Nearly always, a lean condition(detonation or pre-ignition) will show itself with pitting on the pistons. If the pistons are nice and clean, either a plug broke off or you sucked something through the intake and lodged it on the valve burning a hole. I've seen this exact scenario before on a different car.

 

This is why I kept my fire suit....

"Tracking your mini will in no way stress out your plugs, unless of course you have an "on the edge" tune. " Tracking your car stresses everything.....
Racing breeds failure by nature....

Do we know the heat range of the plugs? I don't know that there is any 4 pronged that is a good race plug with the exception of some very high enders.

Yes, both feet in could be an over rev, but a strong down shift could do the same. Cucho could have gone into a corner a little hot. He did spin.

There's still a hole in a valve & no tell on the pistons from a valve.

 

Do you think the codes are gone? Unless they were wiped by the dealer, they should still be there. There should also be some pending codes.

There's still hope!

 

On factory tune ECU you can track a mini hard, all day long and it's a walk in the park. This is NOT racing, it's HPDE. Far different.
On an exteem tune then yes, I agree with you, it's a very bad idea to track your Mini without the correct monitoring devices. It's one reason I cringe when I hear of so many getting these tunes and then go out a compete for HPDE championships.
I was also talking about "Both Feet In" It's one of the first terms you learn at HPDEs. Not sure you understand what this is as it has nothing to do with over reving. It has to do with keeping your motor from reving in the wrong rotational direction in a spin.