So yesterday, I drove my 2005 MCS to my carpool meeting spot. No problems. Got out, locked the car and went to work for my 12 hour shift. When I returned, I hopped in the car, started and let it idle for a couple minutes as I responded to a couple texts I received. Still no problems. Put the car in gear, let out on the clutch, and heard a pop and the car began to idle extremely rough and sounded horrible.

I shut the engine down and opened the hood. Found #2 plug wire boot raised up about 1" or so off the valve cover. Pulled it the rest of the way out and found the spark plug still attached. I then expected the worst, and inspected the threads on the plug. Found nothing out of place. Being as I had no tools on hand, I used the plug wire boot to thread the plug back in as best as I could. Seemed to thread in fine. Figured I'd still have low compression on that, but I only live about 2 miles from the meeting spot, so I limped it home. Seemed to run ok and didn't sound weird or anything.

I'm going to attempt to torque the plug back down when I get home tonight, as I wanted the engine to be cool when I attempt this, but I was wondering if anyone else has ever experienced this kind of strangeness?

I installed the plugs about 40k miles ago using NGK Iridiums. Very interested in hearing any opinions or ideas.

 

What?!?

Are you saying that the spark plug unscrewed and popped out all by itself?

I've never heard of something like this except when timing belt breaks and valves and or spark plugs get blown out of the head by the piston hitting them, but clearly this is not the case fortunately!

I'm interested on how this story evolves!

Cheers and good luck!

 

I've had it happen decades ago on a Honda Prelude. Screwed it back it, torqued it down and never happened again.

It's one of those things, rare but does happen.

 

Actually kinda common on the Mini, were the plugs installed and a torque wrench used to torque them to factory spec? Not saying you didn't do this but a lot of folks don't and end up with plugs blowing out.

 

I'll be honest, no I didn't use a torque wrench to tighten them. I can say I've been working on cars for over 20 years now, owned many different kinds of vehicles and never had this problem before. I'm not to proud to say I don't make mistakes either, so I will definitely be using a torque wrench going forward though.

I really just wanted to see if this had happened to anyone else and if there might be a cause for it. I'm just really glad that it was just a minor inconvience rather than a catastrophic failure.

 

Sounds like you got lucky...I'd tq it...and then check it in a few weeks.....
If some of the threads are gone, you might need to take care of it in the future....

 

Rayanmx, that seems to be exactly the problem. Just backed itself out over time and vibration.

I guess worst case is that I could now justify spending $2000 on a Thumper or RMW head, to the wife! (Because its better than stock and only a few more dollars, right?)

I'd say I'm pretty lucky ZippyNH, provided it just torques down and there is no thread damage. I've never in my life used a torque wrench to tighten spark plugs, but I will from this day forward.

Speaking of can anyone provide a torque value for me?

 

For an R53 torque is 20 ft lb. or 27Nm. according to my Bentley manual that only covers through 2004; should be the same though. Check all the other plugs while you're at it. I do mine twice a year because your experience is a fairly common one since many folks either don't torque enough or use way too much. Hope yours works out fine in the end.

 

20 lb ft or 27 NM. This value is for the factory plugs though. If you're using aftermarket, use the value they provide. Sometimes you have to torque to a value and then add 1/2 to 3/4 turn to flatten the crush washer. Only torque on a cold head, and always allow a few heat cycles and check again.

 

UPDATE: So upon further inspection I have lost the threads on #2, so a thread repair kit will be in order. The crappiest part of this is that a thread repair kit voids my ability to use this head as a core for my Thumper or RMW head. Just kinda sucks all the way around.

From my research it appears that Heli-coil is not a prefered fix, but Perma-Plug Kit #2200-14 seems to be the way to go. Does anyone have any further opinions, comments, or ideas?

 

One tip...
The ONE TIME CRISH WASHERS provided with the sparkplugs when new are...er...one time use, unless you find they were never crushed from never having been tq'd down enough.....
There are other options, like thread-serts, time -serts, etc that work for mist folks, but a full machine shop and head removal or a different head works too....helicoil kits are most common, but are least preferred IMO due to the small grip area, and the fact they often come out with the next plug change...

 

R53 S plugs work loose a 'lot'. No matter if torqued, new plugs or old. The majority of owners either have someone else fit new ones so never know, or change earlier if doing themselves sometimes, so also never see the problem.


I keep taking parts off for one thing or another at the moment, well over the last 18 months while altering, and every time the plugs are looser than when fitted. three different sets of plugs, first or subsequent use, never matters. There's simply a lot of pressure in there, and heat especially when modified, so I for one will continue checking very frequently.


Shame you can't use your head for core, but you can still ask them to modify your head can't you, and just repair the thread, or get them to do it, it will probably be absorbed in the mod cost, or be very little expense.


If I was getting a head done, I'd rather use mine for sure. You never truly know the history behind the core they use anyway. Some are delivery miles but not often these days. I have two spares for this very reason.

 

Next time you do plugs you can use our DIY tech article here as a reference. We also have many others that can be of assistance with any other DIY work here.

-Luccia

 

As others have said, this is unfortunately quite common on our Minis. There are all sorts of ideas why and some are saying it's the brand of plugs, others blaming on if the plugs are put in with a hot or cold head. For me, I use Denso IK20s and install them with the head stone cold. I torque them at install and check them each oil change at 5000 miles and have never had a problem.

Check out this thread and I am sure there are a bunch of others with all sorts of information and opinions.

As I said in this thread, I used a KD BackTap with good luck on a friends Mini but I think we were lucky. If you don't want to take the head off and do the repair on a bench, then look for someone that has the Time-Sert installation tool and pay them to do the job if they won't lend you the tool.

Anyway, you are not alone in this. Take a deep breath and search the forums and you'll fine all sorts of opinions and then you can make a plan.

But the bottom line is that if you just reinstall that plug and you think it's tight, without a repair of some kind, you probably will get stuck further than the 2 miles that you had to limp home this time.

///Rich

 

As a shot in the dark, does anyone have the Time-Sert kit that they would like to sell or loan out (w/ deposit)?

 

I ride a bicycle a lot and every so often I see a lone spark plug lying in the street, so it does happen.

 

+1

My MINI has a Heli-coil repair from the PO in #2. Pulled the plugs this weekend to check them and you guessed it, Heli-coil came out with the plug . I'll be doing a Time-Sert repair soon.

 

I had this same problem, and successfully repaired it with a time sert kit and insert. The writeup of my experience is here:

https://www.northamericanmotoring.co...il-repair.html

My original thread asking about how best to repair stripped spark plug threads (which is full of the same sorts of recommendations you've already gotten) is here:

https://www.northamericanmotoring.co...questions.html

You can often find the Time-Sert 4412E kit (for M14x1.25 spark plug threads) lightly used on ebay. (That's where I ultimately sold mine.) Barring that, Amazon usually has a decent price.

Good luck with the repair, and keep us posted on how it turns out.

 

Alistair, do you recall which size insert you used? I know it's a M14x1.25, but did you use the 15mm or the 16.8mm?

 

Kdelder, based on finromation I found on NAm, I used the 16.8mm inserts (which worked great). I bought this set of five insterts from Amazon (in case I needed more than one):


Unfortunately, I sold the inserts when I sold the tap kit, otherwise I'd offer to send you the inserts.

I hope your repair goes well, and feel free to send me a message if you have any further questions.

 

THE MINI LIVES!!!

Super easy repair if you take your time and follow the instructions of the Time-Sert kit. Thank you to everyone for all the input and advice.

@Stinch, if you want to do the Time-Sert repair, I will let you borrow my kit for a $205 deposit. Upon return of the tool I will refund you $160. Comes with everything you need and I'll include the insert.