Reading My Spark Plugs...Need some Input
Thread Starter
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
Reading My Spark Plugs...Need some Input
Hi Every,
Switched to NGK V-Power TR6's from the factory AC Delco 41-943. The motor has been modified LT1 and is running 11.0:1 compression.
The AC's were white for the most parts, there was some ash/black coloring on the exhaust side of the center ceramic insulator. However, some of the plugs has indications of possibly being too hot (small white speks/***** on the ceramic insulator).
I spoke to NGK tech support and their assessment of the plug was that is was border line too hot and recommended the TR6 as a slightly cooler plug than the stock Delco. Installed the TR6 and the car and the engine temp is about 1-2 degree's cooler at cruise than the Delco's. However, when I pulled a TR6 for inspection, the ceramic electrode was completely white with no color???
I used tune my L98 for a nice tan color, but I just can't seem to get that indication on the LT1. Some respected people have told me that the accuracy of fuel metering on the newer cars doesn't allow the build of a tan/ash color on the plugs. Then when I spoke to Bosch and NGK they both told me to tune for the tan/ash color.
Any feedback into this? How would one gauge if they have the correct spark plug then?
Thanks,
Victor
Switched to NGK V-Power TR6's from the factory AC Delco 41-943. The motor has been modified LT1 and is running 11.0:1 compression.
The AC's were white for the most parts, there was some ash/black coloring on the exhaust side of the center ceramic insulator. However, some of the plugs has indications of possibly being too hot (small white speks/***** on the ceramic insulator).
I spoke to NGK tech support and their assessment of the plug was that is was border line too hot and recommended the TR6 as a slightly cooler plug than the stock Delco. Installed the TR6 and the car and the engine temp is about 1-2 degree's cooler at cruise than the Delco's. However, when I pulled a TR6 for inspection, the ceramic electrode was completely white with no color???
I used tune my L98 for a nice tan color, but I just can't seem to get that indication on the LT1. Some respected people have told me that the accuracy of fuel metering on the newer cars doesn't allow the build of a tan/ash color on the plugs. Then when I spoke to Bosch and NGK they both told me to tune for the tan/ash color.
Any feedback into this? How would one gauge if they have the correct spark plug then?
Thanks,
Victor
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
You want a tanish to white insulator.
On the grounding strap you want it to change color about 1/2 way down, this tells you have the right heat range. If its color change is towards the tip, then its too hot of a plug. If its down, towards the threads its too cold. 1/2 way is perfect.
Now if your getting those small flecks, that is detonation my friend.
Not a good thing.
Your really suppose to read the area just above the threads, on the flat for the correct A/F reading, but I have found that hard to do. Its too is suppose to have a color change about 1/2 way around, for the perfect burn.
Plug reading is a lost art it seems. However it can and does tell you a lot.
The only way to get a good reading is get the car into 3rd gear, assuming auto, and crank it to redline and kill the key, make sure not to lockout the steering. 
Pull of the road/strip return road and pull a plug. They will be extremely toasty to have your knuckle rubbers. 
On the grounding strap you want it to change color about 1/2 way down, this tells you have the right heat range. If its color change is towards the tip, then its too hot of a plug. If its down, towards the threads its too cold. 1/2 way is perfect.
Now if your getting those small flecks, that is detonation my friend.
Not a good thing. Your really suppose to read the area just above the threads, on the flat for the correct A/F reading, but I have found that hard to do. Its too is suppose to have a color change about 1/2 way around, for the perfect burn.
Plug reading is a lost art it seems. However it can and does tell you a lot.
The only way to get a good reading is get the car into 3rd gear, assuming auto, and crank it to redline and kill the key, make sure not to lockout the steering.
Pull of the road/strip return road and pull a plug. They will be extremely toasty to have your knuckle rubbers.
Burning Brakes
Joined: Jun 2002
Posts: 1,159
Likes: 0
From: royal palm beach florida
Originally Posted by ski_dwn_it
You want a tanish to white insulator.
On the grounding strap you want it to change color about 1/2 way down, this tells you have the right heat range. If its color change is towards the tip, then its too hot of a plug. If its down, towards the threads its too cold. 1/2 way is perfect.
Now if your getting those small flecks, that is detonation my friend. Not a good thing.
Your really suppose to read the area just above the threads, on the flat for the correct A/F reading, but I have found that hard to do. Its too is suppose to have a color change about 1/2 way around, for the perfect burn.
Plug reading is a lost art it seems. However it can and does tell you a lot.
The only way to get a good reading is get the car into 3rd gear, assuming auto, and crank it to redline and kill the key, make sure not to lockout the steering. Pull of the road/strip return road and pull a plug. They will be extremely toasty to have your knuckle rubbers.
On the grounding strap you want it to change color about 1/2 way down, this tells you have the right heat range. If its color change is towards the tip, then its too hot of a plug. If its down, towards the threads its too cold. 1/2 way is perfect.
Now if your getting those small flecks, that is detonation my friend.
Not a good thing. Your really suppose to read the area just above the threads, on the flat for the correct A/F reading, but I have found that hard to do. Its too is suppose to have a color change about 1/2 way around, for the perfect burn.
Plug reading is a lost art it seems. However it can and does tell you a lot.
The only way to get a good reading is get the car into 3rd gear, assuming auto, and crank it to redline and kill the key, make sure not to lockout the steering.
Pull of the road/strip return road and pull a plug. They will be extremely toasty to have your knuckle rubbers. 
