Hi everyone,

I'm currently working with a mechanic who does not have a lot of experience working with Mini's. So today he's working on my car, and one of the items I was looking to have done was to have the plugs replaced with NGK Iridiums.

He called me while I was out, and explained that the Iridium plug was a bit longer than the stock plug. Not having a ton of experience with the Mini's, he was hesitant to do the install because he was worried about the amount of clearance between the head of the piston and the bottom of the plug.

Obviously if it were too long, that could result in some damage. He also didn't know if the heads of the pistons were rounded either, giving it a little extra height in the cylinder.

So basically, are the NGK Iridium plugs supposed to be longer than the stock plugs? And if they're not, then that probably means a different plug was shipped to me then, correct?
Any help would be great!

Thanks,
-Dave

PS - He'll send me a photo of the stock and Iridium plug side by side a little later today, I'll post it so everyone can see what we're talking about.

 

Here's the photo, you can see the Iridium electrode sticks out further than the stock electrode, but not by much. (The stock plug is the dirtier one - lol)
He's basically just being cautious, which is totally fine. I'd rather know it'll be ok, vs having him put it in, and it wrecks the pistons. lol

 

wasn't there something, at least a while ago, about these plugs backing off the threads, w/ some even stripping the threads off the engine block? i haven't been keeping up in a while so pardon me if i missed anything, but because of that i always use the stock spec ngk instead of the iridiums

 

Really?
I don't know, but I'd love more input on this.

I did see someone post on another forum about the Iridium's being slightly longer than the stock plug, so they acknowledged that it was longer, but nothing was mentioned about it being a negative either.

I just want to be sure, ya know?

 

I installed the NGK Iridium plugs in my 04 MCS with no problems. By the way, it was not the NGK plugs that were backing out, I believe it was the Densen plugs--

 

Both have done this and I contribute it down to improper installation. Many people don't tighten it down past the compression washer (it gets tight and then loosens again) before torquing.

Anyway, I have been running NGK for several years now. I highly recommend them. They are going to be a little longer, it is normal and won't cause any problems.

 

Thanks for the input Dave!
I had read from someone else that they put Iridiums in their 04 also with no issues. Also, a friend of mine double checked the numbers on the Iridium box vs a web site that sells them for MCS's between 02 and 06, and sure enough they matched.

DaFlake, thanks for the input as well. I think that'll probably do it, as you've confirmed the added length as being ok, with no problems to the engine. (meaning your personal experience with them)

I'll let me mechanic know, he'll be pleased to hear that.
Thanks again!

 

Is this Pete or have you moved? (I doubt it but have to ask)

 

Pete is no longer my mechanic.

 

Fair enough...

 

Always best to put a little antiseize on the threads and torque to 20 ftlbs.
Actually, because of antiseize, you can get a false torque reading, I torque plugs to 18 ftlbs. Remember....only 1 click on the torque wrench is required. Additional clicks actually exceed the torque setting.

Have been using Denzo plugs and never found one loose but, I do check the torque with every oil change.

 

Plug length is based on temperature range. The fact the electrode sticks out a little farther should not have an impact on being too close to the piston. The combustion chamber shape/size should be able to accomodate, not to mention Cooper S pistons are dished for reduced initial compression (8.3:1) to be combined with using boost.

 

Good info to know, Flash. Thanks for that!