How to read spark plugs

Wild one · Jun 7, 2022

One of the better video's i've seen on how to read plugs.

Steve Tech Video - Reading Sparkplugs

Here is how you properly read a spark plug. If you want to learn how to tune any engine WATCH this video!

www.youtube.com

Burla · Jun 7, 2022

Good motivation to get on my tune up, it's on my short list

RLJ10X · Jun 8, 2022

That was really informative. I didn’t know to look at the porcelain.

These were the “Racing Plugs” ( I can’t remember the brand name, they were supplied by ProCharger) that came out of my V6 Mustang when it got Re-Tuned by Lee Blankenship, Nov 2021. Getting the car retuned was money well spent, to put it mildly.

HEMIMANN · Jun 8, 2022

I still have the YouTube cardboard version from the 1960s - from my dad.

Wild one · Jun 8, 2022

HEMIMANN said:
I still have the YouTube cardboard version from the 1960s - from my dad.

View attachment 495022 View attachment 495023

I haven't seen one of those sheets in many years. You used to see them on quite a few walls in the small 2 bay garages/gas stations that were common up till the mid 80's

GTyankee · Jun 9, 2022

I have one or two of those cards
1 of them is tucked between the pages of one of my Motor Manuals
I spent a lot of weekends at Swap Meets, acres of junk & every so often real treasures

RLJ10X · Jun 9, 2022

You will notice on that Champion card, that the porcelains are all different colors. They are going strictly by the electrodes.

Video dude is all about the porcelain. He claims that if your tuner isn’t reading spark plugs the way he says to, he is just a computer operator.

If you look at my six spark plugs, you would swear they came out of three different engines. To me, reading spark plugs has always been a bit of voodoo and black magic. As for me I will trust the hard numbers. I trust my tuner, Lee Blankenship.

Wild one · Jun 9, 2022

RLJ10X said:
You will notice on that Champion card, that the porcelains are all different colors. They are going strictly by the electrodes.

Video dude is all about the porcelain. He claims that if your tuner isn’t reading spark plugs the way he says to, he is just a computer operator.

If you look at my six spark plugs, you would swear they came out of three different engines. To me, reading spark plugs has always been a bit of voodoo and black magic. As for me I will trust the hard numbers. I trust my tuner, Lee Blankenship.

Reading the porcellins has been a fairly well known trick for as long as i can remember.Hotrod mags back in the late 70's talked about reading the porcellin along with the electrode and ground strap.I've always used a magnifying glass to look as far down the porcellin as possible since i was a street racing/nitrous spraying kid back in the early 80's,i still have a magnifying glass in with my Hemi plug checking tools,as i pull at least 8 plugs after every night of racing at the track

Wild one · Jun 9, 2022

RLJ10X said:
You will notice on that Champion card, that the porcelains are all different colors. They are going strictly by the electrodes.

Video dude is all about the porcelain. He claims that if your tuner isn’t reading spark plugs the way he says to, he is just a computer operator.

If you look at my six spark plugs, you would swear they came out of three different engines. To me, reading spark plugs has always been a bit of voodoo and black magic. As for me I will trust the hard numbers. I trust my tuner, Lee Blankenship.

BTW if those plugs are all from the same engine,you had big issues with the tune.Burning the center electrode of the plug to nothing in a couple cylinders,means you weren't checking them often enough,lol

HEMIMANN · Jun 9, 2022

Didn't have 40,000 volts from the coil back then, either.

Wild one · Jun 9, 2022

HEMIMANN said:
Didn't have 40,000 volts from the coil back then, either.

No but reading the plugs was still the same,lol

RLJ10X · Jun 9, 2022

Youre not kidding that tune had big issues! I was never satisfied with how the car ran. But it seemed to really go down hill rather quickly. When that happened, I parked the car for several months. I looked for a different tuner and was lucky to find the one I did.

I'm sorry, but I don't pull spark plugs out to just look at them. lol. Maybe I should. But that ain't me. If that car goes pop, (which it won't) I'll just get another one, something different.

The car is running good now. 357/429 on a Mustang dyno. Well, it did that day. Conditions were nearly perfect. 57 degrees and low humidity.

Wild one · Jun 9, 2022

RLJ10X said:
Youre not kidding that tune had big issues! I was never satisfied with how the car ran. But it seemed to really go down hill rather quickly. When that happened, I parked the car for several months. I looked for a different tuner and was lucky to find the one I did.

I'm sorry, but I don't pull spark plugs out to just look at them. lol. Maybe I should. But that ain't me. If that car goes pop, (which it won't) I'll just get another one, something different.

The car is running good now. 357/429 on a Mustang dyno. Well, it did that day. Conditions were nearly perfect. 57 degrees and low humidity.

If you're gonna run a hi-po car,its wise to get in the habit of pulling the plugs fairly often to check them. I check at least 6 and more often usually 8 plugs with a magnifying glass on both toys after a night at the track. If you can't make the time to stay on top of your toys,you probably shouldn't have them.Just my personal thoughts though.

HEMIMANN · Jun 10, 2022

Wild one said:
If you're gonna run a hi-po car,its wise to get in the habit of pulling the plugs fairly often to check them. I check at least 6 and more often usually 8 plugs with a magnifying glass on both toys after a night at the track. If you can't make the time to stay on top of your toys,you probably shouldn't have them.Just my personal thoughts though.

What're you looking for on the plug? Arcover? Insulation cracks?

Wild one · Jun 10, 2022

HEMIMANN said:
What're you looking for on the plug? Arcover? Insulation cracks?

For me the biggest thing i'm looking for is the burn on the porcellin,and little shiny flecks,i also look at the edges of the ground strap and the electrode.I run copper plugs in the toys,and if the edges of the ground strap or electrode are rounded off,it's time for new plugs,as the spark jumps from the sharp edges,so if the edges are rounded off,that plug is getting close to misfiring. Plus if i see anything that looks shiny on the porcellin/ground strap,i'm sticking my borescope in that cylinder and looking at the piston,lol

HEMIMANN · Jun 10, 2022

Ah.....copper plugs for maximum conductivity. And shortest life, of course.

I've read plugs are toast before the quarter mile in top fuel engines. They essentially diesel to the finish line. That's crazy!
The in-cab go pros can't even keep up during the race - they pixelated.

Wild one · Jun 10, 2022

HEMIMANN said:
Ah.....copper plugs for maximum conductivity. And shortest life, of course.

I've read plugs are toast before the quarter mile in top fuel engines. They essentially diesel to the finish line. That's crazy!
The in-cab go pros can't even keep up during the race - they pixelated.

Even if they turn 9,000 rpm the whole pass the amount of revolutions per pass is alot less then most people think. 9,000 divided by 60 sec's = 150 revolutions per sec ,multiply that by 3 seconds and you have 450 revolutions per pass,add in the burn-out and back-up and you're at maybe a 1,000 revolutions,lol

HEMIMANN · Jun 10, 2022

Wild one said:
Even if they turn 9,000 rpm the whole pass the amount of revolutions per pass is alot less then most people think. 9,000 divided by 60 sec's = 150 revolutions per sec ,multiply that by 3 seconds and you have 450 revolutions per pass,add in the burn-out and back-up and you're at maybe a 1,000 revolutions,lol

Yeah, but IDK what the blower boost and cylinder pressure is, on nitromethanol. I could back calc as bhp = tn, but the NHRA races last weekend claimed 11,000 bhp for top fuel.

Wild one · Jun 10, 2022

HEMIMANN said:
Yeah, but IDK what the blower boost and cylinder pressure is, on nitromethanol. I could back calc as bhp = tn, but the NHRA races last weekend claimed 11,000 bhp for top fuel.

I'm like you,i haven't heard what they pump for boost into the engines these days,but i think they swallow roughly 5 gallons of nitro per cylinder,so when a cylinder goes down and hydro locks,it's a big ass bomb going off,lol.I know they were claiming 9,000 bhp several years ago,so i'd believe the 11,000 bhp claim now.I remember reading a few years back where it took 10 million a year to campaign a second string nitro car,so i wonder what it costs to campaign a winning car currently

HEMIMANN · Jun 10, 2022

Even with all the computer controls today - I still see an occasional blowup. 'Course, it's not like the old days with fans in the stands dodging flaming engine fragments raining down - the kevlar retention straps take all the thrill out of it for the spectators.

How to read spark plugs

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