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General MINI TalkShared experiences, motoring minutes, and other general MINI-related discussion that applies to all MINIs, regardless of model, year or trim.
In short, stop running those goofball JCW plugs that have 4 ground electrodes. Select a "copper" or platinum V-Power plug in the correct heat range, gap it correctly for your application (0.032" for R53's with stock boost levels & 0.030" for mild pulleys), and be on your way. Ditch the Iridium, too.
This should be quoted over and over again. People need to quit making a simple job so complicated! I just read post after post after post and it's no wonder people get so confused when it comes to this.
0.027" is the absolute bottom end of where I'd gap an R53 plug. Maybe if you're stuffing a ton of boost in the chambers, but otherwise you're going to want to open that gap.
I agree with you completely TheBigChill. The reference was for the R56 plug gap. Whenever I've checked the gap on new plugs for my R56 S, whether from the dealer or another source, the preset gap has always been .027" I've often heard people referencing a gap of .032" for the R56 S but that's not where I've seen the gap on a new set of plugs.
I'm pushing 21 PSIg for boost with an RMW tune and I currently have my gap set at .026".
hello folks, i have a 2004 MCS running a 15% alta pulley and cold air intake. the car came with the plugs when I bought it so I don't know what kind of plug I have.
Hi. Part number 8239 is correct for the MSD coil. It also might say it's for Dodge/Mitsubishi. -At least that's what it says on the box of mine. By the way, the only advantage of that coil is that the terminals are plated to reduce corrosion. I replaced mine because OE coil failed, and the price was nearly the same. Your money may be better spent on plug wires, and just clean up your terminals with some emery paper. The MSD 8.5mm Super Conductor Wires were expensive, and I'm not sure if they're better than Napa wires. MSD plug wires are part number 32879.
For plugs (with a 15% pulley), I like NGK BKR7EQUP. It's the factory plug for a John Cooper Works. I bet your plug with heat range 7 will be okay with your pulley. Irradium and Platinum are actually worse conductors than copper, but they do last longer, which is one reason I use the platinums. Also these do not need to be gapped, and have the 4 electrodes.
Change your plugs on a cold engine only, use a torque wrench, threads in your head are on the soft side. Nothing to worry about, just be aware of it and don't over tighten.
How do I know I have reach the correct lbs of torque with a socket wrench?
It is not possible to be precise without a torque wrench. You can get "good enough" with experience, but aluminum threads are a bad place to start getting experience.
Harbor Freight sells a 3/8 inch drive torque wrench for quite a low price. It is adjustable down to 5 lbs. ft. Being Chinese, it may not be as accurate as say Craftsman or Snap-On, but it sure beats guessing. If you can get within 5% of precise you are good. And you can at the very least get all of the plugs at the same torque.
Something to keep in mind about spark plugs is that electricity "likes" sharp edges to jump to and from. That is why Iridium and Platinum plugs last so much longer, they retain their sharp electrode edges much longer. Dirty or carbon coated plugs are essentially widening the gap because the edges are covered up. This is also part of the science behind multiple ground, v-groove, u-groove, and other such plugs. They have more sharp edges so they work better longer.
What a great exchange of information and ideas on Spark Plugs. I am fixing to use this in a class I teach. Thank you to the OP and all you contributors for a great set of posts.
Regarding the claims that Iridium plugs last 100,000 miles. Here's a photo from several years ago of the Iridium plugs that I took out of my 2005 JCW. The previous owner put these in, so they would have been in service a maximum of 50,000 miles. The center pins are gone or seriously corroded on all of them. The old plugs were Denso IK20. The new plug in the center for comparison is NGK BKR7E??? as delivered in this kit in 2012.
Regarding the claims that Iridium plugs last 100,000 miles. Here's a photo from several years ago of the Iridium plugs that I took out of my 2005 JCW. The previous owner put these in, so they would have been in service a maximum of 50,000 miles. The center pins are gone or seriously corroded on all of them. The old plugs were Denso IK20. The new plug in the center for comparison is NGK BKR7E??? as delivered in this kit in 2012.
Follow up to previous photo. Here is today's change-out of those plugs. In at 77,000 miles, out at 118,000, for 41,000 miles of service. Shows signs of wear on plug #4, but nothing like the previous ones. Replaced this with the same kit, including plug wires. Plugs are NGK BKR7EIX-11 IX Iridium Plug.
