Heat marks on plugs

[85Camaro]

Monte, Reading your page on reading nitrous plugs. What I'm I looking for when you say heat make, I have heard if you see any blue it's too hot but could you go a little more into detail about heat marks and how to tell where they are at.

[Monty Mikho]

Yes blue is not a good sign. Usually caused from too much timing. The line is a pretty defined line that looks like a carbon mark. Grab all your plugs out of your motor and set them next to each other. Look for a black carbon mark on the strap. You will see them in different sections on each plug.. unless you have tuned this thing with indepandent spark control and matched all the marks. Let me know if you need more information than that. If is hard to discribe.. when you set the plugs next to each other you will better see it..

[85Camaro]

Thanks Monte going out with a car wed, we will see how it goes

1 More think when clean clipping the engine off top end is it ok to just cut the ignition off at wide open throttle with the nitrous on ? or will cause the engine to back fire?

[Monty Mikho]

DO NOT SHUT DOWN AT WOT!!! Pull the chute (if you have one), lift the throttle, and turn off the ignition.. If it is EFI turn off the fuel pump rather than the ignition... Lifting the throttle will not do much to your plug reading if you let it idle for a few seconds...

[85Camaro]

Ok cool that is what I have done with my car in the past (meaning, lift then shut down) just wanted to make sure I was getting a accurate reading. I was always scared to clip it at WOT. Thanks for the life saving responce :-D

[Monty Mikho]

Worse comes to worse and you have to drive it back. Take some brake clean and spray the carbon out of the plug. It is not as accurate as doing a shut down pass but its better than nothing. For the heat on the strap.. I usually wipe the ground strap with a clean dry rag to remove any carbon build up. You will not rub off the heat mark by doing this.

[85Camaro]

It's cool we have a Golf cart to tow the car back but thanks for the tip just in case the driver forgets to shut it down. Thanks for all you help man it is by far appreciated. It's had to find fellow racers willing to share info. I will let you know how it goes on thurs.

[Bobalos]

Where is the tranny guy on this post? I understand that shutting a motor down @ 150+ MPH is not good for the THxxx Tranny's. somethin about no pump pressure & overspeeding something being driven by the drive shaft.

Bob

[Monty Mikho]

Just leave the car in 3rd gear and you will be fine. DO NOT KICK IT IN NEUTRAL!!! BOOM the tranny will say.. leave it in 3rd till around 50 MPH and you will be fine...

[85Camaro]

Just leave the car in 3rd gear and you will be fine. DO NOT KICK IT IN NEUTRAL!!! BOOM the tranny will say.. leave it in 3rd till around 50 MPH and you will be fine...

Yea I have heard of that before too. Will do, and thanks again!!

[85Camaro]

Forgot to tell ya we never made it out on Wed heading out tonight instead.

[Monty Mikho]

Good luck to ya guys... :D

[85Camaro]

Ok we mad a few passes tonight had some issues but were able to see first hand the heat marks you speak of, and yes they were very noticable when comparing plugs. The car was runing almost perfect on motor on nitrous it was just a tad on the lean side the plugs were white with a small line of brown at the very bottom but the more you went to the back of the motor the leaner they got, to the point of no brown fuel ring. Inspite of the minor problems we had we have a new best time and I beleave there is more in it with some adjustment to suspention and taking some of the delay out of the nitrous off the line. It was kinda of clustered up night but we did what we wanted to due and that was get a good plug reading. thanks for all your help. Hope to have it straight for Stanton NSCA race

[Stiffler]

Keep in mind the line on the center is fuel and the line on the strap is timing, and you want to make them both happy. We keep several sets of drilled odd size jets for splitting hairs...

[Monty Mikho]

God to hear, 85. Like the post above you can stagger your jets to get a better tune up if this is a fogger setup. If not you can use timing controls to adjust each cylinder...