Posting this up for anyone else who has this problem:

3k miles into ownership of my used 03 S, spark plug #1 popped out at highway speeds. I reinstalled it, and the threads seemed to bite, but 10 miles later it popped out again. In looking at the plug wire, it would appear this was not the first time this had happened, and may have been the reason the car was traded in.

I fixed the problem by installing a Time-Sert. The part is about $4, but the extended reach spark plug tool is about $200. A tool guy, I bit the bullet and bought the tool. Worth every penny.

I greased up the tap to catch as many of the chips as possible. Once I had tapped out the hole and re-cut the plug seat, I vacuumed all the chips out of the cylinder (custom attachment to the shop vac using plastic tubing), then blew more chips out of the cylinder with compressed air, then spun the engine over with the key (no plug installed) to blow out anything still left. To clean out the grease, I zip tied a small rag onto a long screwdriver, soaked it in brake cleaner, and swabbed out the spark plug hole and threads.

Next I used the installer tool to screw in the Time-Sert. I installed a new plug, put the wire back on, and all is well.

Take-aways:
-The tool is awesome. Easy to use and it does a beautiful job.
-Do good job cleaning up the chips. Do not expect a greased tap to catch everything.
-Buy a new plug. Do not re-use the old one.
-Make sure you do a good job cutting the seat. This allows the Time-Sert to recess below the spark plug sealing surface.
-Take your time.

Good luck to anyone with the misfortune to suffer this fate.

 

This is a well known issue and my guess would be it was your number 2 plug that blew. Lots of great info on this forum on how to do it.

 

It was #1.

Yeah, I read some of those posts, but thought I would organize my thoughts and memorialize my experience in one post.

 

That would be the first time I have seen that one go. Still, thanks for posting up the info.

 

I changed plugs right after I bought my MCS and luckily saw something on NAM about the plugs blowing out soon after because my plugs were lose by 1-2ft/lbs after only driving the car twice. I tightened them back up again and checked a few days later to find that they were lose again. I am not sure at what point they would blow out, but I am making it a habit of checking them for a while. I may try tightening them slightly above spec next time.

 

Good thing I bought an extra Time-Sert! LOL <sob>

 

I would recommend against that. What I do is at every oil change, 5000 for Artoo, is I check the plugs with the engine stone cold before I start it that day. If I remember correctly 22ft pounds not a single one more.

There are close to 130,000 miles on Artoo now. I changed the plugs at 40,000 and each 40,000 after that. No incident yet or loose plug ever. BTW I use IK-20 DENSOs and a touch of anti-seize on the threads.

That said I have repaired a friends blown plug using a KD Back-tap spark plug thread tool. Worked fine on hers with no problem for years now.

Rich

 

I had the number 3 plug blow out starting out from a stop. It was repaired at a local shop with a time-sert. This mechanic used wadded nylon stockings stuffed down the spark plug hole to catch all the shavings. Then he used a flexible pencil thin grabber claw to extract it. They installed an NGK G-power plug.

The reason they gave for the plug blowing out is that the thread pitch of the Brisk plugs did not fully match the cylinder head threads.

Not to sure if that is true or not, but I switched the remaining plugs to NGKs and things are good. If I ever have to remove the cylinder head, I'm going to have time-serts installed on the rest of the holes.

Brisk plugs were in for 20,000 miles
NGKs have been in for 25k since the repair with no issues.

 

Hopefully you can assist a fellow "disabled"-Mini owner.

I have a 2007 MCS (which I think the spark plug thread is M12 x 1.25, if Im not mistaken)

Does any one know what exact kit or part(s) I would need for this Time-sert procedure?

I know someone mentioned a $200 extenstion arm?

 

http://www.amazon.com/gp/product/B0025NDK7U

 

Thanks for the link!

However I see it is M14 and other reports on this forum state that M56S's have a M12 thread. Can anyone confirm?

 

I know this is an old thread but do you know the size that I would need for the R53? This happened to me this morning on my way to work...

 

Here is what I used when it happened to me:

M14 X 1.25 X 16.8mm Time-Sert

 

14x1.25

There's a complete kit with the 14x1.25, it comes with the tap and three differents depth of inserts, most parts stores should have it.

 

My 2002 MCS suffered the same issue, caused by a Beru spark plug. Mine also blew out pulling away from a stop. I later read the Beru's were known in the UK for not staying at torque, backing out and then eventually blowing out. But I had just enough bite left for a year's worth of driving. Today I was replacing them, back to NKG's, and wasn't as lucky. Threads are to far gone.

This post is probably my solution, but I'll check to see if a local parts store perhaps would loan or rent the tool. Could I be so lucky?

Thanks for posting!

 

Sorry to revive such an old thread.

Having a similar issue with my father's Mini Cooper S and we took the Time-Sert route after the shop recommended a new head, but we are currently experiencing the same P0303 code after installing the Time-Sert.

Is it possible we didn't cut the seat deep enough? We felt a little hesitant about cutting too much but since we are experiencing the same symptoms (maybe slightly less-so), we are considering removing the Time-Sert, cutting the seat deeper, and trying again.

Any help is appreciated, thanks in advance.

 

Cutting to the right depth is important, because you want the plug to seat against the head, not the sert. Regardless, I don't think that's your issue. Have you replaced the plug and the wire...or at least swapped them with a different cylinder to test?

 

Yeah we have swapped everything to see if the misfire followed but it stayed in cylinder 3, that's why we took it to a shop to do a proper diagnosis.

I'm thinking the problem is that the plug was seated against the time sert and not the head. So that poses another question, how do I determine how far down to cut the seat while installing the time-sert?

 

Little update; had a shop help with the Time-Sert installation. Our seat wasn’t cut deep enough and have everything buttoned up. It’s running a bit better but still receiving the same code and awful acceleration. Tried swapping the plugs and coil pack again but no luck. Any other problematic causes we should be looking at?