Plug reading useless

Is learning to read spark plugs worth the effort?

  • Yes

    Votes: 29 100.0%

  • No

    Votes: 0 0.0%
  • Total voters
    29
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MomsDuster

MomsDuster

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I saw a statement on a different forum that said:

Something to keep in mind....If you're trying to read spark plugs, you're pissing up a rope. Contrary to popular beliefs and arguments, you can have plugs that "look good" from a couple of cylinders with one happy and the other ready to eat itself alive. NOBODY in professional motorsports really wastes their time with that because over time they've learned it is not an accurate way to understand what is really happening.

What do you folks say? Me? Well as far as I’m concerned it’s an extremely valuable skill to have. Just another tool in the tuneup box.
 
That guy is a FOOL. An O2 sensor will lie it’s *** off to you. A plug won’t. Evidently the guy can’t even half assed read a plug or he wouldn’t have said that.
 
When I was in training for a "regular" mechanic I was taught to read plugs for a/f mixture as part of a tune-up.

I never knew about reading for timing until I joined this forum. Seems to me that's the more important thing to learn.
 
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Being in the pits during professional big name drag racing, I can tell you from personal experience that plug reading is not "pissing up a rope".
 
The plugs tell you more about what is going on in the combustion chamber than ANY other way of reading a state of tune.
 
So if you pull a plug thats oil fouled, thats not telling you something?
Guess I've been doing it wrong the past 50 plus years
 
Rat Bastid said:
That guy is a FOOL. An O2 sensor will lie it’s *** off to you. A plug won’t. Evidently the guy can’t even half assed read a plug or he wouldn’t have said that.
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Dang right ratty. You got somethin right anyway. lol
 
I'll keep reading my plugs I feel there's a lot of information there.
 
Plug reading is highly valuable, and a lost art these days. The plugs tell you what is happening in the combustion chamber of each cylinder and informs what is actually happening inside them without guessing.

Sure, plug temp and gap can change the results a bit, but if they are relatively close to each other throughout the engine, the information the plugs provide is solid evidence of what’s occurring inside each combustion chamber across the engine.

Only a fool would ignore such definitive information.

No good scientist rejects solid data to help inform their conclusions.
 
I think I know what the OP meant, but a blanket statement like he made doesn't cover it.
Really hard to get a read on the colour of the plug electrodes these days with all the different fuels around. But if the plugs are black, you know you have a problem, so removing plugs to check is not a wasted effort.
 
Bewy said:
I think I know what the OP meant, but a blanket statement like he made doesn't cover it.
Really hard to get a read on the colour of the plug electrodes these days with all the different fuels around. But if the plugs are black, you know you have a problem, so removing plugs to check is not a wasted effort.
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That's very true, but initial and total timing marks are still a constant regardless of fuel, as they rely on heat.

The key to reading plugs is, knowing WHEN and WHAT to read. In other words, if you read plugs that have been idling for 20 minutes, you're gonna see RICH plugs. LOL
 
Sound like 'bot logic to me. Also, be sure your tire pressures are spot on, one tenth of psi off and you are in da weedz...
 
Only thing I can read on my plug is C-H-A-M-P-I-O-N, although N-G-K must be foreign? Would be a great sticky in the tech section! Or is it?
 
Ok how bout I say it this way, build a 400hp NA street engine like 90% of the stuff out there and ignore your plugs. You’ll likely be just fine. BUT build anything with forced induction or nitrous or with significant HP and ignore your plugs and you’ll be in big big trouble. I don’t care what fuel is in it.
 
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It's not as good an indicator as it used to be for pump gas, and of course differs depending on where you're at, but 'useless'? That's ridiculous.
I've noticed a difference though, in how the pump 91 we get out here the last few years reads. It just doesn't color up the insulators like it used to on a comparable tune.
O2 sensors are great but they don't tell you squat about timing, heat range, is there un-heard detonation..
 
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