I have searched through various threads but could not find an answer to how often to change the spark plugs on my JCW/GP. I saw intervals from every oil change to 100,000 miles. Since the intercooler has to be removed to change the plugs on the GP, I do not want to change them more than necessary but I also want to change them frenquently enough to maintain optimal performance.
I am thinking every 30,000 miles, which I just passed.
Any other interval suggestions?
I plan to install Brisk Silver Racing plugs # BRSK-DR12S.

 

30K miles in the orig spark plugs should still be OK.

 

To take a guess, I would say every 75k miles; I would stay with the original plug, there is nothing to be gained by going aftermarket. Many owners went aftermarket and had problems with the plugs.

 

The standard non-JCW non-GP is supposed to be replaced at 100k miles according to MINI. That being said I replaced mine at 70k to attempt to fix a low-rpm idle shudder/stutter issue and noticed an increase in throttle response. For JCW and GP cars Todd Pearson found a BMW/MINI tech service bulletin stating the JCW plugs be changed at every oil change. His dealership initially had no idea of this and did not wish to replace them but did so when they saw the bulletin.

 

The Mini TSB indicated above is actually the JCW installation instructions that come with the kit (if dealer installed). You should be able to find it at

http://www.motoringfile.com/howto/JCW_MCS_install.pdf

Basically, it says that the JCW spark plugs "should be fitted at each subsequent service and maintenance interval."

I seriously doubt that many (if any) dealers will honor this as part of the service program. My dealership told me that they follow the 100K mile interval of the Cooper S...basically I have to shell out the cash (and lots of it) if I were to have them do it. No thanks. I have cheaper alternatives!

I heard somewhere that the iridium used in the JCW spark plug will wear down faster than the standard Cooper S platinum plug, and should be replaced at around 25K miles...or very roughly equivalent to every odometer indicated service/oil change.

 

Listen this is not true. If that were the Case it would be on our inspection maint sheet. We use daily when we service these cars. I know for the JCW you supposed to replaced the drive belt on the inspection but plugs hmm nope. These plugs are good plugs they last along time. Some times I pull plugs on these cars @ 50-70k on some of the early one.s Because customer want to replaced them due to age. They look good ,good burn time to them.
its rec @ 100K. But for customer pay what even the customer wants they get.

 

Thanks for the first-hand info, guidmini! You are a service tech, after all! Its funny the different responses that I've heard on the subject, as other people have sworn that the iridium was well worn to the point of needing replacement after @30K. Don't ask me where I heard it from as it is Friday and my brain is functioning at the minimum level, but I swear I heard it somewhere! Perhaps for the DIY'ers, just pull them out and check them out every 30K to make sure that everything is ok

 

I have an '05 MCS/JCW, and like you, I found the info to be conflicting. So, being an overkill type of guy, I changed the plugs at 20K miles. The difference was amazing! Much better throttle response and idle quality. I likewise changed them at 40, 60, and 80K with the same drastic imprpvement each time. The OEM plugs are all I've ever used, but I started buying them from www.sparkplug.com and the price was ~$7 each instead of $40 each from the stealer.

I know some might think I over-maintain my cars, but I know that it has worked for me so far. I also change my oil every 2500 miles.

Rawhyde

 

Hey Rawhyde,
I appreciate and think i agree with you on OEM plugs at short intervals.
How about plug wires?
was thinking of a change there too at 40K but have read some bad things about aftermarket wires.
Are you still on OEM wires.
thanks
boxcars

 

I change wires every other plug change. (Every 40K miles)

 

I remember now where I heard of the roughly 30K limit to the JCW plugs: Motoringfile/WhiteRoofRadio. The crew at WWR were talking about how the plugs were definitely going at around 30-40k, with hesitation and drop in gas mileage. If you still have a service contract, try telling them of intermittent hesitation/mileage drop to see if they will replace them.

 

Could that have been sparkplugs.com (with an s)? Without the S you get some sort of child psychology site.

Also, which brand iridium plug have you been using on your JCW?

 

I have always used the OEM JCW plug. I just found it cheaper at the sparkplug site.