Thank you for this tutorial.

I'd just like to comment that after extensive research, here are some little known facts:

• Factory plug (at least for AP1) is the NGK PFR7G-11S
• NGK PFR7G-11S is ONLY available from the Honda dealer, part number 98079-571BH
• NGK PFR7G-11S are specifically pre-gapped at 0.039 from Honda, what the engine was designed for--other plugs are the WRONG GAP
• Billman does NOT recommend gapping these pre-gapped plugs--they should come perfectly gapped from the dealer
• NGK 98079-571BH is recommended for 75k-100k intervals
• The "S" stands for washer--the washer was added because a lot of plugs from the early years were backing out and damaging the engines
• IMPORTANT: Proper torque is between 20-22 foot-lbs (as stated by Billman)

A lot of people debate about Iridium vs Platinum, or even worse, copper plugs. The head/block is aluminum, so copper plugs with their low life-expectancy are a big no-no. The car runs much smoother for me now that stock plug is back, with the proper gap. Unfortunately since you can ONLY order these from the Honda dealer, most people are using the wrong plugs. The correct plugs are special order folks. Summary: Order from the Honda dealer, look for the red box, part number 98079-571BH.

 

The NGK IFR7G-11K S, Stock No. 7746 is the Premium Laser Iridium plug available for the S2000.

 

Understood. The research I noted above was for the Platinum, custom-gapped plug for the s2000 -- PFR7G-11S (Platinum),

Hopefully Billman will chime in on his thoughts on whether the "IFR7G-11KS" (Iridium) are appropriately gapped for the F20C/F22C.

Do you have a Honda part number where you can purchase the IFR7G-11KS pre-gapped at 0.039 from a dealer, because the NGK spec sheet shows the "normal" version of that plug as gapped to .044" (which is probably NOT correct for the s2000).

 

I ordered NGK PFR7G-11S plugs from Advanced Auto. Be here Thursday. Never heard it's a Honda Special order part. If the number is right, am I good to go?

 

That's exactly why I'm posting this--most people don't know or care that it's special order.

The Advanced Auto plugs will probably not be gapped correctly (and it is not recommended to re-gap these at all).

See here:
https://www.s2ki.com/s2000/topic/917...t__p__21270928
https://www.s2ki.com/s2000/topic/454...h-spark-plugs/

 

It's not recommended to reuse alignment adjuster bolts, but we re-use them anyway. It's not recommended to re-use the subframe bolts but we do. It's not recommended to re-use axle nuts, but we do. If you know how to do it you can adjust the gap on the plugs, just very carefully and slowly bend the ground strap without touching the electrode tip. You have to be very careful, you can only bend it once, and your wire feeler gauge can also damage the electrode tip, so if your gap is too tight you basically ruined the plug. Tightening the clearance, you just put the plug in your plug socket and push the strap slowly against something rigid and metal. Luckily any NGK platinum plug you buy will either be just perfect, or a hair loose.

 

I don't recall the exact gaps from the NGK plugs I bought, but I think they were all .40. In any event, its important to have proper plugs before you get started.

 

You can go on the NKG website and watch their own video on the proper way to gap these plugs if you need to. I ordered the stock plugs off a reputable site on eBay (half the price of the dealer) and they came perfectly gapped. However, for my other cars, I have needed to gap one or two that were not perfect: just a smidgin.

 

99% of us are not old-time racers, but shade-tree mechanics who want to avoid dealership maintenance because they won't do it correctly half the time (and charge twice as much in labor).

I don't know why Billman and many others insist on NOT re-gapping, but that's what they've said for years and I have more peace of mind doing it the "correct" way. As for re-using subframe or alignment bolts--those are multiple points of failure with a higher margin of error. If even one of your spark plugs fail and bounces around in your cylinder, your engine will be toast.

I am able to get the correct plugs for $15/each or $60 for four. Try Majestic Honda or http://hondapartscheap.com for up to 30% off on OEM/dealer parts (and sometimes no tax). That's $2/plug more expensive than Advanced Auto/Autozone/etc. and $5/plug more expensive than Amazon (vs. the cheaper WRONG plugs as of time of writing). Not much of a premium to do it correctly out of the box. Admittedly I'm not a materials engineer or pro mechanic, but if you're comfortable with the risk/reward, go for it.

https://www.s2ki.com/s2000/topic/830...t__p__19835451

 

Every NGK for the S I bought was either right on the money, or .002" loose, I've never had a tight one. I've seen people drop them and bend them tight, I tell them to get a new one. Either way you should be careful about touching the tip more than anything, any pressure on the tip will transmit to the rest of the plug, including the ceramic which is considerably weaker than the metal, if this cracks, it's complete engine annihilation sooner or later. Bending a piece of steel with a zinc coating that is essentially bonded to the metal it's on won't cause anything to break in the plug. This is because the strap is joined to the metal threads of the plug and not the porcelain core like the electrode tip is.