While most problems have been with '02-'03s, later heads have suffered this problem as well now so it might just be age (or that higher mileage cars are more likely to have replaced plugs). Extreme temperature changes may simply compromise the gasket seal over time with the dissimilar metal expansion rates (for the same reason you can't expect a head gasket to last as long when the head is aluminum and the block is iron even when using expensive MLS gaskets) if not tight enough, and it's not unusual that one plug runs hotter than the others in many engine designs. Perhaps MINI just tightens them near the high end of the spec? From a year ago:
FWIW I torqued my Autolites to 24 ft-lbs, and the gaskets are definitely flattened from all the fitting during indexing.

 

OK, so this is a problem with stock plugs properly installed, not just aftermarket incorrectly installed.

That is my point, if the problem were somehting else, then the result would occur randomly with any cylndner. The fact that is always #2 on ealry model cars screams defect to me.

Well, the truth is that I'm still going to have to take care of this myself. If there is a class action, though, I will for the first time in my life join in it gladly.

 

Not quite sure why you pulled me into this thread.

The problem with plugs being blown out seems to only happen when using the Denso (which has no listing for MINI) or NGK plugs. I have yet to see a single complaint from anyone running stock plugs. To add to this, I have seen no benefit from running these plugs anyway, even with a reduction pulley. The professionals that I have spoken with don't even recommend them.

So, if there is no gain and only a risk of stripping the head, why run them?

Pointless if you ask me as the stock plugs work fine.

Lastly, this is not bound by model year, so I really don't follow your point. One guy had an 06 #2 blow.

 

I thought the oem plugs were NGK? They say BMW but look exactly like the NGK 4 prong Plats...I would be amazed if anyone only made a special plug for the Mini. I replaced my aging oem's with NGK Iridiums (same heat range, torque, etc) and knock on wood...so far all is ok...but I am now checking torque every 1000 mi. (still do not think this is a normal situation though....)

Sometimes I think I should put my old plugs back in...This should not happen in today's world.

 

I agree, it shouldn't happen. I didn't mention that it typically was with colder plugs that this happened not standard. NGK WEB sites states that they support MINI so I would think that they should be OK.

They have these listed...

Cars, Trucks & SUVs
2006 MINI COOPER S 1.6 L4 FI Supercharged
V-Power
G-Power Platinum
Laser Platinum
Iridium IX




Also, looks may be decieving as metals may be different. Frankly, we don't know who supplies MINIs plugs. What we do know is that some people that have put colder plugs in have had problems and nothing is gained by running them.

 

Thank you Daflake.

I was beginning to doubt my sanity regarding my Mini. It is a 2004 and only has 20k mi. It has to go back to the dealer come spring (stays garaged in the winter) to have a sized power steering fan replaced (250 mi RT!)

As much as I love to drive it...the number of problems reported (So far mine has only had the Window regulators go bad and the Coolant turn brown with lowered protection)...maybe I will get out while the gettings good!) the number of problems reported recently has made me think of selling it come spring and surrendering the fun! It was bought used and solely for the fun factor (not my daily driver)

Happy Hollidays

 

Daflake, it's because you summarized all that we know so nicely last year, and this topic keeps popping up. BTW if you reread my post you should note that I agree with you that nothing has changed on the newer heads.

 

Ahhhh, I totally misunderstood you. Sorry.

 

As an update to my situation with the MCS: I towed it to the local dealer and perhaps because I went through a contact within the dealership who knows me from the BMW Club, I actually got a good will offer from MINI. They were willing to split the cost of a replacement head. My cost would still be $1800.

I considered the offer fairly strongly, but when I asked to speak to the field rep myself I was told that he would not budge since the spark plugs had been changed and they can't be sure that they were "installed incorrectly." The rep never did call me nor would they give me the number to contact him myself. I still maintain that the non OEM spark plug defense is very weak. As my wife pointed out there was no assurance that the new head would fix the root cause of the problem. With no admission of responsibility I figured I was better off on my own.

I did a successful spark plug bore rethread without removing the head. Kits are available at parts stores. They are, appropriately enough, called spark plug thread repair kits and are not helicoils. Helicoils are a wound metal wire. These kits have an actual metal sleeve insert that is threaded on the inside and outside. A liberal application of heavy grease on the thread tapping tool trapped almost all the chips. I checked the cylinder bore and there were a few chips and grease that fell through. I vacuumed them out with a 1/4 inch plastic hose taped to a shop vac hose. The car now runs as good as before. The only issue left is the 'service engine' light that needs to be reset.

 

That is good to hear. Typically re-threading is as strong or stronger than the original. I think that you will be in good shape.

 

One of the guys above wrote, "The professionals that I have spoken with don't even recommend them." This is in reference to replacing stock spark plugs with different, sometimes colder range, plugs. In contrast, the professionals that I have spoken to, which are the ones that sold me their 15% supercharger pulley, recommended a spark plug change. Just goes to show you there can be many opinions.

Hey Prima,
Great job! Glad you shared your story. It demonstrates there is no need to panic, pull the cylinder head, or spend way too much money on this kind of repair.

 

That would be me and if I were a vendor, I would try to sell you additional items as well...

 

Can you tell us exactly what kit you used? Brand, size, part#, etc. That would be most helpful.

Great news that you fixed it!

 

funny that, dflake. the vendor recommendation to use cooler range plugs with a smaller supercharger pulley was not associated with a sale of said spark plugs from subject vendor. not that it matters to you, but climate is a factor, as well.

 

Not sure who you spoke with on the matter so I really can't say. I do know that MINI-Madness recommends it on their site which is why I stated what I did. I run a 15% with stock plugs and persoanlly don't see a reason to go to colder plugs but the choice is yours.

I could see running colder plugs if you track the car, but most people don't.

 

Waylon from Way Motors did my pulley at the Dragon, and suggested IK-22s. He did not have any for sale, but did suggest where to search to find them for cheap.

 

I had my #@ go this past Friday evening. I pulled in to get gas and when I started it up it sounded like a full race exhaust. I opend the hood and the plug wire was sitting on top of the head. I found the plug and thank goodness a kid ditting next to me was a auto student and had all the tools needed to put it back in. It seemed to to him to screw right in without any prblems. So I checked and re tourqed the next moning and so far no problems. THe question is,am I goint to be alright or am I doomed. How can I check to be sure I don't have any stripped threads down that long dark hole!!! Thank for you guy's help... Maybe a Cosworth head might have to be ordered.....

 

stock plugs? what year of car?

(just curious, came across this thread. hoping it ain't a major issue if you keep the stock plugs).

 

03S with Densos. It's funny I noticed a little blow by in the day's before but @ 10degrees outside it was a little cold to go outside and check.. (I know, I know I should have) Never the less what's done is done I just want to know if since it's holding tourqe will it be OK. I may just replace with stock just to be on the safe side..

 

Well, just to add data to the list.. WIth an '02 MC, 150k miles, I change my plugs myself at about 100k. Replaced with same NGK ones recommended b MINI. Don't have a torque wrench, just put them in and gave it under all-I-got. Checked now, and they were /slightly/ loose. Nothing to be concerned about in my book. No difference between #2 and the others, either.

 

I have to check exactly the brand. I seem to remember it being a Car Quest branded item (that is where I bought it), but that is only the printing on the carboard insert of the bubble pack. I'm sure it's available in other brands at other chains. As for size it is 14mm dia (consistent with the spark plug size). The kit comes with three lenghts of inserts Our plugs are 3/4 inch long. The kit was $50, but that included both tools and inserts. I would bet/hope I can get the inserts for less should I ever need to do another one.

This was suggested to me by Rick Ramsey and he held my hand throughout the job. If anyone else had suggested it, I would have balked at the idea. When I mentioned it to my wife she asked if I was going to do this or Rick was. Apparently she has no faith in my ability, for some reason.

 

Helicoil is the most well known. NAPA sells them also under the Balkamp name.

 

Rick is a great resource. He can hold my hand anytime...er, well, you know what I mean.

Thanks for the info. I will file this away in the hopes I never need to refer to it!

Brad

 

It may be a semantical point but these are not Helicoils. Helicoils are expressly not indicated for spark plug bore repairs. A Helicoil (known generically as wire thread insert) is a square wire wound up in a tight coil, hence the name. Helicoils are intended for repair of fastener threads such as you where would insert a bolt to keep two parts together. You can pull a Helicoil apart like a spring. http://www.emhart.com/products/helicoil.asp

These are actually inserts or solid metal bushings that are threaded on the inner and outer diameter of the insert. This is a link, which is apparently sold under the Helicoil brand name. Mine weren't branded that way, but the package looked almost the same. http://www.globalspec.com/FeaturedPr..._x_125/23773/0

 

That's called an insert as apposed to a Helicoil.

BFG9000 called part of the problem, on the money. Cold plugs, like the Denso, don't expand at the same rate as the head. After several TQs the crush washer does a better job with the differing expansion rates, allowing a much better seat in the head. The fact that we see more Denso plugs with this problem is a red herring. Almost every brand of plug will do this. It's the installer not using the proper TQ & not checking the TQ 600 - 1K later.