Rich or Lean?

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mullinax95

mullinax95

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I pulled my spark plugs today and was wondering what you think.

Rich,lean or just right?

I always need a second opinion because I might think what looks good might actually be bad.


Isn't most correct way to read plugs is to shut the motor off as you go down the road, pull over and then read them? I've seen this done before put don't messing around with hot plugs. Can you read them more or so less like this? I drove the car today, let it idle for about 3 minutes, pulled into the garage and shut it off, pulled the plugs.

DSC02091.jpg


DSC02094.jpg
 
Mully, do you have a Chilton's or Haynes manual laying around your place somewhere? There's a full-color spark plug comparison / troubleshooting chart on the inside back cover of most issues that should be a big help to you.
 
That tan colour looks pretty good. I agree with Leanne. Get the pics from the manual. A magnifying glass will help look for signs of detonation.
 
CudaChick1968 said:
Mully, do you have a Chilton's or Haynes manual laying around your place somewhere? There's a full-color spark plug comparison / troubleshooting chart on the inside back cover of most issues that should be a big help to you.
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No I don't but I do look it up on the Internet and compare them that way.

It just does not compare to what the members here have got to say ... especially the racers, machinists,etc..

Why fool with the rest when you ask the best!:-D
 
MtNemoMopar said:
That tan colour looks pretty good. I agree with Leanne. Get the pics from the manual. A magnifying glass will help look for signs of detonation.
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What do I look for exactly to find detonation?

The plugs have a slight carbon film on the outer ring.
 
detonation will sort of look like little welding splatters, or melted pits. Your plugs look clean to me, and the heat pattern looks pretty good too. I can't explain this very well, so I would keep asking the Bro's here....and the Sisters. And research all you can on the 'net. It's fairly simple on a regular car, and hard to get too picky, as the conditions change so much(traffic, highway, idling, cold, hot....)
 
trust me I have been reading my plugs for years they are perfect.if you had any dentonation severe that is you would be missing pieces of thoes plugs.if your still concerened jet up 2 sizes then read again.do you feel any serging at cruising speeds does it heat up a tad thoes are singhs of a lean mixture.
 
Lite Brown is perfect, stay away from white=lean and black=rich. Also detonation will cause broken electrodes, among other things and if you every see little tiny silver specs or balls that's the piston and that would be bad. Oh ya, yellowish build up is antifreeze cuss believe it or not it does burn.

Terry
 
MtNemoMopar said:
detonation will sort of look like little welding splatters, or melted pits. Your plugs look clean to me, and the heat pattern looks pretty good too. I can't explain this very well, so I would keep asking the Bro's here....and the Sisters. And research all you can on the 'net. It's fairly simple on a regular car, and hard to get too picky, as the conditions change so much(traffic, highway, idling, cold, hot....)
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OK brothers and sisters it is... lol!

I know what you mean about the conditions change.
 
Snake said:
trust me I have been reading my plugs for years they are perfect.if you had any dentonation severe that is you would be missing pieces of thoes plugs.if your still concerened jet up 2 sizes then read again.do you feel any serging at cruising speeds does it heat up a tad thoes are singhs of a lean mixture.
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I have to keep my eye out for detonation because I'm running 10:7 compression. I run the highest octane available which is 93 octane. The heads are 302s that have been cut down to 57cc combustion chambers. Whenever I take the heads off again I'm going to more than likely install larger exhaust valves and round off the sharp areas in the combustion chambers.

No it runs smooth and stays in the 180* range.
 
to check your plugs during load, run it hard thru the gears, after 3rd or 4th gear, let off the gas and shut the car off, pull over to side of road(desolate area), and pull plugs. You need to get that reading to truly read the plugs under load.
 
If you're running 93 octane pump gas, the plugs are perfect. That's excactly what they should look like when burning properly. If you were running leaded race fuel they'd be lean. That sandy brown color on your plugs is the key to a clean burn. If you run the car hard, then check them hot. But if your not drag racing the car, checking them cold is just fine.
 
redfastback said:
BTW, what is your timing at???
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34* total past 2500RPM

I can't remember the initial.

Demon416 said:
If you're running 93 octane pump gas, the plugs are perfect. That's excactly what they should look like when burning properly. If you were running leaded race fuel they'd be lean. That sandy brown color on your plugs is the key to a clean burn. If you run the car hard, then check them hot. But if your not drag racing the car, checking them cold is just fine.
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Yeah I've learned something today about the tan. thanks.
 
Looks pretty darn good Ax. It would be nicer if they were allexactly the same color, but there's bound to be some fuel distribution uneveness.
 
I like the color of those plugs. Fuel distribution is not perfect but not real bad either. And I like the fact you are running Autolites, great plugs.
 
If I may add my humble $.02,
mixture distribution may be an issue, but before I chased that
I would correct the plug gap and center electrode to ground
electrode alignment.
(forgive , I suck at paint files, so verbally I go)

first pic, compare plugs #1 & #2 (ground to center electrode alignment is way off) also gap on #3 looks short.

second pic, #2 ground electrode looks "bent" off center from
pos electrode. #4 looks (maybe camera angle) like the gap is long.

lastly, all the ground electrodes
show a fairly even heat transfer.
and the nice tan color ...ist goot..

hope the verbal visual makes sense.
 
Do you have a choke? If you do, set it to pull off a little faster. They are close. If you're in a climate like CT, leave them. Because when it's cool, it will be perfect, and when it's warm, it's not really that rich. If this were a tuning for the track deal, I think it's a hair rich. Maybe not jetting, but power valve timing or too much squirtor or too slow a choke setup. Modern cleaner fuels and good quench and tight chambers should not have much or any carbon present, but a choke equipped, or one that idles a lot, or where the carb might not be perfectly tweaked will look just like that. Detonation is when the conditions in the engine or the fuel allow for a 2nd flame front to develop when the mixture is fired. As these two fronts meet, tremendous stress is introduced to the chamber, head gasket, piston, rods, bearings, crank, and block. It is not always audible, but by careful looking, you'll see bits of piston material that is hammered off the piston and sticks to the ceramic. You need a magnifier to see it, and as mentionned, you see tiny flecks of silver or bluish black spheres stuck to it.
 
340sFastback said:
I like the color of those plugs. Fuel distribution is not perfect but not real bad either. And I like the fact you are running Autolites, great plugs.
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I agree, autolites can even stand up to large doses of nitrous if the everything else is set up right. Good stuff.
 
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