NGK BR4HS - Iridium or other upgrade?

I checked the dome clearance before I used them and I was surprised how much vacant space there was. It was like the size of an expresso cup.

If the plugs threads stick out into the combustion chamber that's not a good thing as hard carbon deposits can tear up the heads threads when you take the plug out for what ever reason you need to take the plug out for. I also if I think of it I'll power wire brush the new plugs threads and a little dab of never seize on the threads and everytime I round trip a plug and have access to a wire wheel and never seize I do this. To clean the plug hole a little spray of carb cleaner but I don't do this unless it looks really nasty.What about the nasty that goes into the cylinder you ask. Well I hope it goes out with the exhaust on the first time it fires as aluminum powder that fine in the never seize will burn and burn clean up and out the pipe it goes. what do yo think is in the good old firecrackers aluminum powder and potassium chlorate and maybe a pinch of flowers of sulfur.
Norman

Good point - easy enough to assure this doesn't happen.

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Gosh Dag it Norm! You had me worried so I put on my parka & gloves and went into my freezing (55 degree) cold garage to check out my plug. After taking it out, it looked nice with a tanish brown color to it. LOL I have about 100 miles on it only.
It's probably b/c I use a mix of 110VP(1 part) and 92(3 parts) octane gas with Castrol 747 oil.

Quit your whinning cold shop. Mine is 20 degrees and I did all the posts for the carb pictures. Well I did cheat a little fired up the heater. I've got a stock head I could take a shot of a plug in it and if I can find a plug too long I could take a shot of how it would look. The power wire brushing thing I learned the hard ways some time a new plug will have a little burr where the ground electrode is welded on the plug and it acts like a lathe bit when you screw it in cuts nasty new threads so I try to make sure that the threads are clean and no burrs and the never seize will stop aluminum and steel from gaulling in most cases and it helps seal the plug. A LITTLE goes a long ways beleive me I look at neverseize and seems pretty soon I'm wearing the shlt all over me.

Head what it looks like.




Head with too long of threads on plug and wrong plug just to show.



head with stock china plug and a couple of the threads showing on the head



If you pull off the head I like to resurface the head on a pane of glass with 320 wet/dry sand paper glued to the glass and wet sand it to true it up. I use water on the sand paper with a dash of soap in the water to help keep the paper from clogging up with the sanding dust. All I do is get the contacting surface a dull uniform color all the way around so this goes pretty quick. I have not done this head the area in question is what looks like a narrow ring on the head.

My first NGK B6HS and the stock plug are so soaked and fouled from the super rich conditions that they gave up the ghost. It probably didn't help that the aluminum anti-seize was washed down and around as well.

I'm convinced a B6HS is not the best plug for cold, wet conditions and first start/tuning conditions. I may return to it in the summer though.

SO I just received my two B5HS plugs that I bought on eBay. (great seller) I was not having luck finding B4HS or B5HS locally. And it seems B4HS is just a complete rarity. So now it's wait for decent weather and free time!!

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Refresh my memory....don't NGK plugs get hotter with a higher number?

It's the opposite:

NGK Spark Plugs USA

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Thank you! Yes, now I remember, they are opposite of most plugs.