posted a video in the original post

 

Do not start the car again. All your doing is making it worse. Pull the head, check your walls and take your head to have the valves looked at. 1 of 3 things have happened...

1. The tip broke off and bounced around hitting the valves and head and now your valves won't seat making your car have a miss fire. This is my number 1 guess.

2. Coil pack is burnt up because of the bad plug. Put a new coil pack in and see if that works. Tip of the plug went out the exhaust after bouncing around for a sec.

3. Tip broke off and trashed your wall , piston and the rings. You have low compression.

 

If you have a cylinder not firing your wideband will read leaner as the cylinder is just pumping air through it into the exhaust. A wideband can not detect or measure raw fuel.

 

~10k miles on plugs ur supposed to change every 5k.... best of luck

 

Were thinking the conductor may be in between a valve and a seat, which may have just bent a valve. I'm gonna splash a bit of ATF in there and let it burn off to try to get everything out and see if it helps, and if not, Ill be taking the head off to assess the damage. Hopefully it's just gonna need a valve job, and I can upgrade the springs and retainers while im in there anyways since it's an older engine

 

Your cylinder #1 plug was not tighten properly. The "extra torque" you claim to have used is distortion of the threads from intense heat of blow by.

It pulled air past the threads, leaned out the cylinder, the spark plug tip glowed until it became molten, and melted off into the cylinder.

It did not break off.

These are the facts, 100%.

I'm my opinion (which is usually right) you have cylinder damage from liquid metal dripping on the piston head and being blown into the cylinder walls by the piston coming up at high speed and blasting the drip of molten metal. I've seen it too many times to be wrong.

I guarantee you 100% the piece did not break off and bend a valve. It melted off.

All this from an improperly tightened spark plug. Note the carbon on the silver part. This is combustion blow by.

More facts...not a guess. sorry man..

 

I agree with this guy above me. If I were you I would go buy a compression tester an see what it reads. Or do a leak test an listen for any leaks. If all is good I would change out your coil packs or see if someone will let you use theres for a test.

I just put new plugs in mine an my NGK writing color was blue an I see that your is black. Are you using the correct plugs for your S2000? I think you might have put a to hot of a plug in also.

 

Good idea....leakdown is your most powerful diagnostic tool in your situation...provided the guy knows how to read it, adjust it, and interpret where the bypassing air is heading.

A "mechanic" will tell you what % of leakdown you have in cyl 1.
A Technician will tell you where that % of air is going (past the intake valve, exhaust valve, or cylinder). Or spark plug threads if he's really DUMB

 

Billman is correct. You can also do it at home and set your compressor to low pressure with a regulator an listen for a leak in your exhaust, throttle body or anywhere else. Im sure there is a DIY online somewhere.

 

And even before that, were you knocking or running really hot? In the beginning with my engine problems, it started to get really hot in general under there and when I changed my plugs, one of the electrode grounds was bent to the point of almost touching the electrode. Sadly, yes, rebuild time. Drop in a new short block and call it a day, you can get them for about 3k NIB from Honda.