PLUG READING FOR A NITROUS MOTOR

General Nitrous Discussion

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John_Heard
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#16 Post by John_Heard » Wed May 25, 2005 2:02 pm

Welcome to the site Robert :)

Yes, that pass had too much timing in it. It's hard to distinguish pepper from oil/detonation or if it's from the electrode. But you're right, there are signs on the electrode that it's too hot in there. Same on the ground strap for that pass.

Mooreboys

Reading Plugs

#17 Post by Mooreboys » Wed May 25, 2005 10:23 pm

I can see now that I am not checking the plugs close enough. I guess
us Nos GreenHorns have a lot to learn. I really appreciate you fellows sharing information the way you are. It really helps us on our learning.
Have raced for years on the motor only......Built new engine for Nos this past fall and trying to get things base lined with out hurting it. Thanks to Dave Koehler for his input. What a nice person to help like he did. Maybe we are on right track now. Thanks to all!.
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#18 Post by Doc Holiday » Sun Jan 22, 2006 2:52 pm

Here is a plug from my engine after a nitrous pass. Let me see if I have this right. Where the brown ends on the ground strap is my heat mark, correct? So, since its so high on the strap, that means I should try to add a couple degrees of timing, right? I'm shooting for the heat mark to be about where the strap meets the base if I understand correctly. I'm not sure how to tell if the plug looks lean or not though. My thoughts is that it looks good, but I'd thought I'd throw this picture on here to get a second opinion. This is using C16 gas. Whats the verdict? How do I know if the plug is too cold or too hot?

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#19 Post by John_Heard » Sun Jan 22, 2006 10:11 pm

Doc Holiday wrote:Here is a plug from my engine after a nitrous pass. Let me see if I have this right. Where the brown ends on the ground strap is my heat mark, correct?
Yup, looks like it in that picture.
Doc Holiday wrote:So, since its so high on the strap, that means I should try to add a couple degrees of timing, right? I'm shooting for the heat mark to be about where the strap meets the base if I understand correctly.
This is where you start watching closely what you're doing, yes it might be able to take 1 or two degrees more, however I'm not all that familar with those plugs or that type of engine. I don't think I would put much more in it from where you're at. Maybe try 1 more and see how the car performs. Most people recommend stopping at the curve on the ground strap (in reference to the plugs in the earlier pictures). Some will chase it a bit more past the curve if the car responds to it, but got to remember you're on the upper end of how much timing you should be running at that point. If you see black specks show up, take timing back out.

Doc Holiday wrote: I'm not sure how to tell if the plug looks lean or not though. My thoughts is that it looks good, but I'd thought I'd throw this picture on here to get a second opinion. This is using C16 gas. Whats the verdict? How do I know if the plug is too cold or too hot?
It looks pretty darn close on the plug heat range, the center porcelin is nice and clean, so it's getting hot enough to burn off any deposits there, but it's not hot enough to melt the glue around the center electrode or get any damage to the electrode. The C16 doesn't color a plug a lot so it's kinda hard to tell from the picture, but I don't see any signs of it being rich at all - you do however need to look down at the base of the porcelin to see what the fuel ring looks like.

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#20 Post by Quijinn » Sun Feb 05, 2006 6:19 pm

Hey all new guy to the board. I stumbled across it when I was looking for pointers about reading plugs. Wow I was amazed to see how much I didnt know. I Drag race bikes, my current is a 1300cc Hayabusa. Well I also have a Stealth twin turbo I been working on. So as I been looking for info I found this site I notice you guys dont have a turbo section, so hopeing this will be ok here in the NOS :)

I would like to post some plugs and have you all tell me what you think, now this is a turbo motor and not sure if it really applys. So please just give me your ideas, thanks. If there to big let me know I will resize thanks.


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92 Dodge Stealth twin turbo, and a 05 Suzuki Hayabusa. Both built to do what they do best, go fast.

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#21 Post by John_Heard » Mon Feb 06, 2006 10:47 am

Quijinn about all I can tell from that plug is that it's plenty hot enough to burn the deposits off the porcelain when driving around. The base of the plug is real black, which shows that the motor is probably rich at least at some time when it was running. I'd suggest putting in a fresh plug and making a pass then pull it out without as little idle time as possible and then let us take a look at it. Also cut the threads off like in the previous pictures so we can see what it looks like at the base of the plug.

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#22 Post by Quijinn » Mon Feb 06, 2006 4:13 pm

I have 2 extra plugs I have to mail order them in no one carries them so I dont wana cut them up yet. Only 350 miles on them, but I have changed fuel system, injectors and exhaust since then. I will put one new plug in and make a run. This is so cool I am haveing fun with all this stuff haha.

Ohh and the plug is 2 ranges colder then stock, NGK thats why I have to mail order them in. Sucks haveing to shut a turbo motor off right after a pass cause the turbo is oil cooled. Oil cooks into the bearings if done to many times :cry: Still though once in awhile should not hurt I think :wink:
92 Dodge Stealth twin turbo, and a 05 Suzuki Hayabusa. Both built to do what they do best, go fast.

shocker
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#23 Post by shocker » Sun Aug 13, 2006 10:37 am

HI
this is my first post
but would like to share what happens to plugs when your tuner ups to 100 shot of nos on a k20a honda engine and forgets to fit colder plugs
don
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GrandSportC3
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#24 Post by GrandSportC3 » Fri Jan 19, 2007 8:55 am

Can anybody help me to read my plug?

Those plugs are from a 406 SBC (approx. 650 HP on engine) and a 100 shot of nitrous (Edelbrock system).

The plugs are heat range 8 and are NGK v-power racing plugs with .033 gap. The fuel was Sunoco 112 leaded

The rim looks light to medium gray, the electrode is medium gray on top and black in the back and the porcelain has solid black spots left and right (no peppering).

Does anybody know what this indicates?

Here are the pics:

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'68 Corvette Convertible, blue/white 10.351 @ 130.15 mph
'68 Corvette Convertible, yellow
'05 Corvette Convertible, triple black

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#25 Post by John_Heard » Fri Jan 19, 2007 10:52 am

Nothing personal but your pictures kinda suck. I can't see real well what's going on there. The soot on the porcelain I can see, I'm guessing these plugs were some you drove around on then made some nitrous passes with?

If so it almost looks like those areas were shielded from the heat a little by the electrode and didn't get hot enough to burn off the carbon. Notice how they look like a shadow of the electrode... Kinda interesting actually if you think of the heat in the combustion chamber radiating out like light would. The timing mark on the strap looks pretty good.

Anyway, that's my take on it. I'd suggest starting out next time with fresh plugs with no driving on them, then pull them after a pass and take pics.

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#26 Post by GrandSportC3 » Fri Jan 19, 2007 11:17 am

Beyond wrote:Nothing personal but your pictures kinda suck. I can't see real well what's going on there. The soot on the porcelain I can see, I'm guessing these plugs were some you drove around on then made some nitrous passes with?

If so it almost looks like those areas were shielded from the heat a little by the electrode and didn't get hot enough to burn off the carbon. Notice how they look like a shadow of the electrode... Kinda interesting actually if you think of the heat in the combustion chamber radiating out like light would. The timing mark on the strap looks pretty good.

Anyway, that's my take on it. I'd suggest starting out next time with fresh plugs with no driving on them, then pull them after a pass and take pics.
The car is a race car only and I don't drive it on the street anymore.. The plugs were brand new when I made the pass... I actually went from #6 plugs to #8 plugs when I added the nitrous..
My camera has autofocus and it can't manage to focus on the plug correctly.. I took about 30 pictures and those are the best ones...
'68 Corvette Convertible, blue/white 10.351 @ 130.15 mph
'68 Corvette Convertible, yellow
'05 Corvette Convertible, triple black

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#27 Post by John_Heard » Fri Jan 19, 2007 11:54 am

Did you make a motor pass first before the nitrous pass or something? Surely those pictures aren't from a plug that only made one nitrous pass and were fresh at the start of the pass were they?

You might try taking your pictures outside in the sun or with a flash next time, that might help.

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#28 Post by GrandSportC3 » Fri Jan 19, 2007 12:32 pm

Beyond wrote:Did you make a motor pass first before the nitrous pass or something? Surely those pictures aren't from a plug that only made one nitrous pass and were fresh at the start of the pass were they?

You might try taking your pictures outside in the sun or with a flash next time, that might help.
I did not make a motor pass before.. I did however drive around the track to warm up engine and transmission before my first pass..
I launched on engine and hit the nitrous in 2nd and partially in 3rd gear.. Had to get off the nitrous as the car was starting to sway really bad shortly after the 1/8 mile..

I tried to take the pictures with the flash but the colors were distorted.. It was dark outside when I took the pics last night.. Might try to get some daytime pictures some time this weekend.. I'll be out of town today and tomorrow, so I'll only be able to take the pics on Sunday.. I'll post better pics then!
'68 Corvette Convertible, blue/white 10.351 @ 130.15 mph
'68 Corvette Convertible, yellow
'05 Corvette Convertible, triple black

Image

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#29 Post by rsracer » Tue Jan 23, 2007 7:51 pm

What kind of tool are you guys using to cut of the threads from the porcelin?
Never have run the qtr with the BBC in it, but it runs 5.20's on the plate in the 1/8 th on 28's.
Runs 5.40's on 26 x 10's on a plate.

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#30 Post by John_Heard » Tue Jan 23, 2007 7:58 pm

On mine I just use a little chop saw I have with an 1/8" blade, or could use a cut off blade in a die grinder, something like that works ok.

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