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Old 04-21-2015, 12:02 AM   #1
wolffcub
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What do you think of my plugs?

Had the truck at 2200 ish rpm on the road then shut her down and pulled the plugs.






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Old 04-21-2015, 09:33 AM   #2
Apachemike
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Re: What do you think of my plugs?

What gap are you running
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Old 04-21-2015, 11:08 AM   #3
wolffcub
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Re: What do you think of my plugs?

Im running HEi so I have a larger gap. think its .06 odd. Cant remember off the top of my head but i can always verify of check my record sheet when i get home.

Just wondering if some others might think its lean. Nothing i can do anyways as the jets for the carbs i have are impossible to get.
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Old 04-21-2015, 11:55 AM   #4
dwcsr
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Re: What do you think of my plugs?

Looks good, the heat line is half way down the strap where is should be, the ceramic is clean and the bottom ring where the strap is weleded to is consistant in color and not to dark or light. I'd say your on the money.
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Old 04-21-2015, 12:12 PM   #5
OrrieG
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Re: What do you think of my plugs?

Looks good to me too.
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Old 04-21-2015, 01:58 PM   #6
dwcsr
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Re: What do you think of my plugs?

For what ever reason only the last picture showed up when I looked at this before, but now in order of the pictures. #1 ok, #2 hot, #3 hot, #4 hot, #5 hot, #6 ok

you see the whitish color on the ground strap and the electordes, they should look like 1 & 6. The color change on the strap should be on the middle of the strap not at the bottom. This means the heat is leaving to quickly into the base.

Don't look at porcelain for a rich/lean reading, the base ring where the strap is welded is what you look at for rich/lean it should not be black of have soot deposits but it should have a full turn of dark color. If it only has a color change halfway around then its to lean. black sooty all the way around or black speckles to rich

I think your fuel mix is probly ok but I'd go to a rj14yc and test as you did . 2200 rpm then all off, no idling or driving. Best way is a A/F meter from jegs or summit. They are fairly cheap and a good way to dial in the carb. You don't need a wide band one just the cheapy will do it. It just take a few minutes to warm up before you get good readings.
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Old 04-21-2015, 02:13 PM   #7
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Re: What do you think of my plugs?

Quote:
Originally Posted by wolffcub View Post
Im running HEi so I have a larger gap. think its .06 odd. Cant remember off the top of my head but i can always verify of check my record sheet when i get home.

Just wondering if some others might think its lean. Nothing i can do anyways as the jets for the carbs i have are impossible to get.
HEI gap max is 0.045
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Old 04-21-2015, 02:25 PM   #8
mr48chev
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Re: What do you think of my plugs?

That looks about as good as you are going to get with today's gas. I used to be able to read plugs pretty well but can't grasp the look of the ones with this junk gas we have now.

On spark plug the earlier (75,76.77 or so )engines called for a pretty wide gap and the gap got smaller as years progressed and engines went to fuel injection.
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Old 04-25-2015, 12:24 AM   #9
wolffcub
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Re: What do you think of my plugs?

Quote:
Originally Posted by dwcsr View Post
For what ever reason only the last picture showed up when I looked at this before, but now in order of the pictures. #1 ok, #2 hot, #3 hot, #4 hot, #5 hot, #6 ok

you see the whitish color on the ground strap and the electordes, they should look like 1 & 6. The color change on the strap should be on the middle of the strap not at the bottom. This means the heat is leaving to quickly into the base.

Don't look at porcelain for a rich/lean reading, the base ring where the strap is welded is what you look at for rich/lean it should not be black of have soot deposits but it should have a full turn of dark color. If it only has a color change halfway around then its to lean. black sooty all the way around or black speckles to rich

I think your fuel mix is probly ok but I'd go to a rj14yc and test as you did . 2200 rpm then all off, no idling or driving. Best way is a A/F meter from jegs or summit. They are fairly cheap and a good way to dial in the carb. You don't need a wide band one just the cheapy will do it. It just take a few minutes to warm up before you get good readings.
Got some new rj14 plugs. **** to gap them to the .065 as they are not a wide gap plug I guess. Put about 30 miles on the truck and pulled the plugs. All look the same. Im not sure if trying to gap these new ones at .045 is worth a try as the last go around with the rj18'a re gaped to a .055 made it run horrible with no power.



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Old 04-25-2015, 09:51 AM   #10
1project2many
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Re: What do you think of my plugs?

You're close. Carbed inline manifolds won't give perfect mixture at all cylinders. Cruise can be a usually bit lean as long as you're running lighter loads on fairly level ground. A more responsive power valve or PE system can allow lean cruise without worry about detonation or excess heat in the chamber. Tuning the engine to close parameters like that takes frequent checks and incremental changes. Start on the rich side for safety and work your way leaner.

Timing advance might be a tad high as well. With the heated intake I'd tend to run less timing at cruise. The mixture will light easier due to the heat. Ultimately you'll have to tune for the plugs showing the worst readings. If the some are showing more heat, either due to poor fuel distribution or slightly advanced timing, you'll need to get them right.

Is this engine fairly new? If so, it's likely to want less fuel after it's run in for a bit. Keep track of these settings... you might return to them after a few months.
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Old 04-25-2015, 10:24 AM   #11
tmoble
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Re: What do you think of my plugs?

GM ran plug gaps from .045 to .080 with HEIs. There's nothing special about .045, it was just the most common.
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Old 04-25-2015, 12:30 PM   #12
enaberif
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Re: What do you think of my plugs?

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Originally Posted by tmoble View Post
GM ran plug gaps from .045 to .080 with HEIs. There's nothing special about .045, it was just the most common.
There are guys who have run dyno runs on plugs gapped higher than 0.45 and found that unless you have a REALLY high end HEI system you actually start loosing spark instead of gaining anything.
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