Help Reading Spark Plug

[bob58o]

Predator 212cc Hemi
gx390 carb
0.026 Pilot
0.042 Main
Fuel Screw Two turns out
32 degrees BTDC
0.030 Coil Gap
11.1 to CR
100 octane race fuel
AR3911 racing spark plug
Factory Gap ? Didn't measure
Gravity Fed Carb

Killed at WOT.
About 30 minutes total driving on this plug, mostly at WOT.

1. incorrect main jet?
2. incorrect spark plug heat?
3. Incorrect timing?
4. Looks ok, or too hard to tell.

 

[bob58o]

Another view

 

[bob58o]

I can get more pics.
I know a guy. Lol

 

[Hellion]

Catastrophic failure. Replace plug. I am thinking timing and you experienced severe detonation.

Or that's the first two-piece spark plug I've ever seen. Cool.

 

[bob58o]

Catastrophic failure. Replace plug.

Or that's the first two-piece spark plug I've ever seen. Cool.

Have you seen this poll feature before?
I could have made more specific options but wanted to test her out.

 

[Hellion]

Yes, and I voted just now.

 

[bob58o]

Yes, and I voted just now.

Can you be more specific than my poll was????

 

[Poboy kartman]

Just going by retail price....that's a "rich" plug....JK...

Looks rich to me.

 

[KartFab]

intial thoughts I have are

1) plug couldnt handle the heat
2) why jack with timing if you don't get a cam with a cam card and follow the specs for timing per the cam you get?

 

[Poboy kartman]

You guys are missing it COMPLETELY! The plugs didn't come apart ON THEIR OWN!

Somebody suckered Bob into believing you have to destroy spark plugs to read them.....because you need to read the porcelain WAY up in the plug.

So my question to this "expert" is this? When the "working" part of the plug is black....and the porcelain is white.....is it rich or lean....or just Michael Jackson's affliction?

 

[mckutzy]

Yes good question... Why are these being disassembled?

 

[bob58o]

intial thoughts I have are

1) plug couldnt handle the heat
2) why jack with timing if you don't get a cam with a cam card and follow the specs for timing per the cam you get?

Cam asks for 32 degrees, which is the key I have installed.

I was thinking I wanted to try again with the AR3910X that I have. Now that I know how to cut a plug up, I can get a better look.

I'm not sure what kind of reading I can get with this gas.
Also this may be a trick question as timing, heat, AND AFR are all related.

I think I will start over with the colder AR3910X and the 115 jet.

Keeping the plug heat and the timing constant, I will go by feel (decreasing the main jet) until I think it is close.

I think this is the safest way to go about it?

---------- Post added at 05:24 PM ---------- Previous post was at 05:23 PM ----------

OH!

I cut the plug to look at the end nearest the threads with my 4.5" Angle Grinder!

LOL

 

[Poboy kartman]

Yeah..Bob...you still don't get it.....I'm a cruel SOB....I was just waiting to watch you destroy some plugs...before I said anything....

You can see ALL you need to without destroying them.

HMMMMM....Ever wonder why EVERY plug reading chart shows WHOLE plugs...

DUH!!!!

 

[Flyinhillbilly]

It's lean on the main, no carbon ring around the base, idle looks rich. Can you post a side shot of the ground strap?

---------- Post added at 06:32 PM ---------- Previous post was at 06:31 PM ----------

You guys are missing it COMPLETELY! The plugs didn't come apart ON THEIR OWN!

Somebody suckered Bob into believing you have to destroy spark plugs to read them.....because you need to read the porcelain WAY up in the plug.

So my question to this "expert" is this? When the "working" part of the plug is black....and the porcelain is white.....is it rich or lean....or just Michael Jackson's affliction?

Yeah? Watch this.

 

[chancer]

If you can adjust the poll Add a 5th box that says:
■ I don't know how to read a plug either.

That way you don't leave anybody out. Since right now I am feeling left out,
I am going to retreat to my "safe space"

 

[Flyinhillbilly]

After looking at this pic a little closer I think the jetting is pretty close, I didn't realize the well part of the plug was so shallow. I'd restrict the low speed air bleed, and pull some jet out of the low speed circuit. The ring where it tapers up to the point where the metal meets the porcelain should have a dark grey ring all the way around it. All the soot on the threaded body is what's telling me the idle is fat. Under wot the heat will burn the carbon off of the porcelain to the point of being completely white if it's too lean. If that circle goes all the way around leave the main jet alone and play with the idle and transition.

 

[Hellion]

I'm gonna leave my spontaneous exploders here just to destroy this awful, misleading poll thread. CLOSEUP photos of the electrode next time, please.

Thanks, genius.


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[Joe-405]

that looks lean to me actually. Whats it doing ? Or are you just asking ? If you have a drill numbered set go one size bigger than the hole. And possibly down a few on the idle jet.

 

[Poboy kartman]

that looks lean to me actually. Whats it doing ? Or are you just asking ? If you have a drill numbered set go one size bigger than the hole. And possibly down a few on the idle jet.

R U KIDDING me? LEAN? Are you used to reading plugs dissected or whole?

What are you looking at?

Remember....Bob doesn't have a lot of hours on these plugs....the porcelain STARTS OUT WHITE!

 

[Joe-405]

2 things to remember. These are air cooled and need to run rich to run cooler which means more power. Also it's summer time so this is the richest the engine is gonna be for the whole year. I can tell you the plug that was in the barstool for 2 years and I've never had an issue with was closer to black than the usual tuned goldish color. And it's always ran perfect. Easy to start never cut out. Never missed the rpms once.