Spark Plug Reading - How Do Mine Look?
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Spark Plug Reading - How Do Mine Look?
Decided to pull & check the plugs tonight. I suspected for no apparent reason that my car has been running lean. So a plug check was in order.
[edit]
I know I'm burning a little oil. I went through about 1-1.5 quart or so in 1200 miles and I know that I'm leaking some too. It's definitely guides more than rings.
My engine is running:
SINGLE PLANE Torker II intake
292H Cam with 0.516 lift = VERY RICH idle
[/edit]
I found that they all had:
Mostly GRAY electrodes
Some black ash around the base
In no particular order, here are 4 of them. The color on the pics might be a little off since I had to mess with the digital pics a little for brightness & contrast.
So what do you think?
[Modified by ddecart, 9:58 PM 7/30/2002]
[edit]
I know I'm burning a little oil. I went through about 1-1.5 quart or so in 1200 miles and I know that I'm leaking some too. It's definitely guides more than rings.
My engine is running:
SINGLE PLANE Torker II intake
292H Cam with 0.516 lift = VERY RICH idle
[/edit]
I found that they all had:
Mostly GRAY electrodes
Some black ash around the base
In no particular order, here are 4 of them. The color on the pics might be a little off since I had to mess with the digital pics a little for brightness & contrast.
So what do you think?
[Modified by ddecart, 9:58 PM 7/30/2002]
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Re: Spark Plug Reading - How Do Mine Look? (ddecart)
Not an expert, but from what I know I would guess that you are running a dual plane intake. You may have to run staggered jetting because the plugs look so different.
1 looks a little rich, not horrible but a little rich, probably at idle
2 A/F ratio looks better, but the oil is a problem, valve guides, rings?
3 looks pretty good, little oil on the threads
4 Has me a little perplexed, the ground strap is very light colored (Usually lean) but the porcilen is rich looking, again a lot of oil.
Does the car puff smoke on start (Valve guides) or when you stomp on it (Rings)
1 looks a little rich, not horrible but a little rich, probably at idle
2 A/F ratio looks better, but the oil is a problem, valve guides, rings?
3 looks pretty good, little oil on the threads
4 Has me a little perplexed, the ground strap is very light colored (Usually lean) but the porcilen is rich looking, again a lot of oil.
Does the car puff smoke on start (Valve guides) or when you stomp on it (Rings)
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Re: Spark Plug Reading - How Do Mine Look? (69 N.O.X. RATT)
I'm running a Torker II single plane intake with a Holley 600 double pumper carb.
With the big cam I have (292H with 0.516 lift), I'm running WAY RICH at idle. I'm talking 15 seconds in the garage and your eyes are watering. It's the best I've been able to get SO FAR with my cam & carb though. I need to work on the carb but haven't had time.
With the big cam I have (292H with 0.516 lift), I'm running WAY RICH at idle. I'm talking 15 seconds in the garage and your eyes are watering. It's the best I've been able to get SO FAR with my cam & carb though. I need to work on the carb but haven't had time.
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Re: Spark Plug Reading - How Do Mine Look? (69 N.O.X. RATT)
After some picture viewing in a manual I have. The 2nd one is probably same as 1st and 3rd, it picked up some sludge on the way out it looks like and threads are oily. I bet valve cover is leaking above it. The 4th one is either overly rich or your burning some oil in that cylinder. It looks more like oil though :(
Scott
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Re: Spark Plug Reading - How Do Mine Look? (Matt Gruber)
600 DP holley; isn't that a racing carb?
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Re: Spark Plug Reading - How Do Mine Look? (ddecart)
The 3rd plug is how they all 'should' look. :crazy:
....What's your ignition setup ? ....I'm suspecting that you're not getting a decent spark due to wires, distributor, or something on the ignition side.
The oil burning just 'adds' to your problem. :chevy :seeya
....What's your ignition setup ? ....I'm suspecting that you're not getting a decent spark due to wires, distributor, or something on the ignition side.
The oil burning just 'adds' to your problem. :chevy :seeya
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Re: Spark Plug Reading - How Do Mine Look? (verskel)
The 3rd plug is how they all 'should' look. :crazy:
....What's your ignition setup ? ....I'm suspecting that you're not getting a decent spark due to wires, distributor, or something on the ignition side.
The oil burning just 'adds' to your problem. :chevy :seeya
....What's your ignition setup ? ....I'm suspecting that you're not getting a decent spark due to wires, distributor, or something on the ignition side.
The oil burning just 'adds' to your problem. :chevy :seeya
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Re: Spark Plug Reading - How Do Mine Look? (ddecart)
I would say it is a little rich. It wouldn't hurt to jet down a size or two. Match your power valve with your idle vacuum, that could help things (if you haven't done it yet). You know, idle vacuum - 2 = power valve rating.
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Re: Spark Plug Reading - How Do Mine Look? (burners)
I've got the power valve all set with the vacuum. I'm running only about 10" of vacuum at idle. I think i have a 6.5 power valve.
I'm wondering if the deposits are more from the engine being so rich at idle and not so much at speed. I guess I should install an O2 sensor. I have a home-built O2 gage sitting in place of my Ammeter already. just need to do the dirty task of getting the sensor & welding a bung to the exhaust.
I'm wondering if the deposits are more from the engine being so rich at idle and not so much at speed. I guess I should install an O2 sensor. I have a home-built O2 gage sitting in place of my Ammeter already. just need to do the dirty task of getting the sensor & welding a bung to the exhaust.
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Re: Spark Plug Reading - How Do Mine Look? (ddecart)
How can anybody "read" plugs that have been in the car forever? The short answer is that you can't.
Put brand new plugs in the engine. Make a hard WOT run down the quarter mile or somesuch and immediately CUT THE IGNITION at the end. This is called a "clean cut" and it's the only way to get an idea of where your mixture is.
Even allowing the engine to run after you go through the traps and driving the car back to the pits can affect the plug reading. The only thing anyone can tell from your pics, unfortunately, is that you have a slight oil control problem.
Put brand new plugs in the engine. Make a hard WOT run down the quarter mile or somesuch and immediately CUT THE IGNITION at the end. This is called a "clean cut" and it's the only way to get an idea of where your mixture is.
Even allowing the engine to run after you go through the traps and driving the car back to the pits can affect the plug reading. The only thing anyone can tell from your pics, unfortunately, is that you have a slight oil control problem.
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Re: Spark Plug Reading - How Do Mine Look? (The Dude)
fwiw, these plugs have about 1500 miles on them. A good hunk of that was constant freeway cruising to and from Bowling Green.
I disagree with not being able to tell anything from plugs that have been in a car. If there is a problem, it takes time for deposit to form. While a clean cut check like you're saying will give a good indication of rich/lean, I don't think that it will tell the whole story. Granted, in my case where I know I have a vary rich idle that needs some butterfly modification to fix, there are conflicting influences on the plugs.
btw everyone, my heads don't have that many miles on them since a rebuild with new guides. A couple/few thousand miles maybe. I'm NOT real happy with the job they did. Anyone have a set of Dart Pro-1 heads they want to give me? :D
I disagree with not being able to tell anything from plugs that have been in a car. If there is a problem, it takes time for deposit to form. While a clean cut check like you're saying will give a good indication of rich/lean, I don't think that it will tell the whole story. Granted, in my case where I know I have a vary rich idle that needs some butterfly modification to fix, there are conflicting influences on the plugs.
btw everyone, my heads don't have that many miles on them since a rebuild with new guides. A couple/few thousand miles maybe. I'm NOT real happy with the job they did. Anyone have a set of Dart Pro-1 heads they want to give me? :D
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Re: Spark Plug Reading - How Do Mine Look? (The Dude)
Dude
before i got the A/F sensor i believed those instructions.
However, at least in my car, which idles at 13:1, plug color is determined by WOT. i noticed this, or rather confirmed this by reading the exhaust valve color with the heads off.
idling does not seem to "heat set" the plugs/valves. (Not sure about other cars, how would i know?, that is why they sell A/F gauges) :lol:
before i got the A/F sensor i believed those instructions.
However, at least in my car, which idles at 13:1, plug color is determined by WOT. i noticed this, or rather confirmed this by reading the exhaust valve color with the heads off.
idling does not seem to "heat set" the plugs/valves. (Not sure about other cars, how would i know?, that is why they sell A/F gauges) :lol:
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Re: Spark Plug Reading - How Do Mine Look? (Matt Gruber)
dave
when is the last time you tightened the intake bolts? lots of people forget this and have oil leaks :eek:
when is the last time you tightened the intake bolts? lots of people forget this and have oil leaks :eek:
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Re: Spark Plug Reading - How Do Mine Look? (Matt Gruber)
Yeah, I suppose the clean cut method is pretty "old tech." I mean, the guy I learned it from built Darrel Waltrip's carburetors during the 1980's.
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Re: Spark Plug Reading - How Do Mine Look? (The Dude)
dude
the method works (limited only by the plug reader)
no doubt about that. However shutting off the engine and coasting home is not required (just makes it more fun i guess)
but a racing carb might be set up different, so anyway you want to tune is fine with me. just make sure you get the guy you wrote about to do it. But, sadly, for the now obsolete professional plug readers, guys can buy an A/F gauge and he is out of a job :sad:
[Modified by Matt Gruber, 1:37 PM 7/31/2002]
the method works (limited only by the plug reader)
no doubt about that. However shutting off the engine and coasting home is not required (just makes it more fun i guess)
but a racing carb might be set up different, so anyway you want to tune is fine with me. just make sure you get the guy you wrote about to do it. But, sadly, for the now obsolete professional plug readers, guys can buy an A/F gauge and he is out of a job :sad:
[Modified by Matt Gruber, 1:37 PM 7/31/2002]