what is the spark plug gap for an '02 MC?

[Jeffy]

I just special ordered NGK iridium plugs and didn't get the usual acompanying gapping info. The gap they were sent with seems really small for a modern ignition system. Thanks for taking the time! -Jeffy.

[k-huevo]

As for the pre-set gap, it depends on the model number; if it is BKR6 EIX the gap is .030”, BKR6 EIX-11 has a pre-set of .044. For the Cooper a gap of around .044 is OK. The OEM multi-prong plug has a gap of ~.068 but that does not cross apply to a single prong. If you have an EIX, use a wire gapping tool to adjust.

[Jeffy]

So mine are under gapped. Thanks for the tip! -Jeffy.

[Jeffy]

If you can provide more energy to the plugs through higher output coil, low resistance sparkplug wires or better sparkplugs, you can use a bigger sparkplug gap, which can result in more efficient combustion and fuel economy. I stole tricks from Dr. Christopher Jacobs of Jacobs Electronics. He had a very good book out, in which he explained how this is possible. The book is a bit old, but the concepts are still useful. The book is titled "The Doctor's Guide to Optimising Your Ignition". I first applied some of his tips to my Datsun 240z, which was suddenly easier to start, gas mileage significantly improved and performance also improved(ignition timing curve info). On my Mini I used the .044 gap with iridium plugs and low resistance plug wires. I haven't figured the mileage difference yet, but I like it.
Gas prices are going up, but we have the right car- both performance and economy. How can you beat that? -Jeffy.