cylinder 1 spark plug oddity

longbedGTs

high on gas fumes
After putting some miles on a set of new Autolite 23s gapped at .025, it looks like there's a problem with cylinder #1. Take a look at the pic. I'm running dual nozzle alky, so is that why the other plugs are so clean? Also, running an RJC power plate. Does it look like the alky isn't making its way to cylinder #1? Why would that be? The plugs are situated as they came from the motor...1,3,5...and 2,4,6.

Also did a warm compression test. Numbers are:
cyl #1-150psi
cyl #3-150psi
cyl #5-160psi
cyl #2-147psi
cyl #4-156psi
cyl #6-146psi

Specs:
8.7 c/r, 216/219 roller cam, cnc series Champion iron heads, 124lb injectors, 6466BB
 

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TexasT

Texas, Where are you from
Alcohol squirted into the up pipe isn't exactly a good way to get an even amount into each cylinder. Good for cooling the charge. Not so much if you are trying to add additional fueling with it.
 

longbedGTs

high on gas fumes
A dual nozzle with your et/mph is a lot of alky.....but doesn't explain only one plug affected.
This problem is on the '87 GN...which has just gotten a combo from a member here who went stage 2. He was running E85 and I'm running pump 91 with alky. The TT chip is burned for the pump gas combo, but I don't recall the timing. Powerlogger is showing about 17deg at partial throttle, but no WOT yet as I am easing into tuning this to avoid any engine damage.
 

Mr.Spool

Well-Known Member
Alcohol squirted into the up pipe isn't exactly a good way to get an even amount into each cylinder. Good for cooling the charge. Not so much if you are trying to add additional fueling with it.
This is not true
I've run over 50gph through the up pipe.
 

Mr.Spool

Well-Known Member
After putting some miles on a set of new Autolite 23s gapped at .025, it looks like there's a problem with cylinder #1. Take a look at the pic. I'm running dual nozzle alky, so is that why the other plugs are so clean? Also, running an RJC power plate. Does it look like the alky isn't making its way to cylinder #1? Why would that be? The plugs are situated as they came from the motor...1,3,5...and 2,4,6.

Also did a warm compression test. Numbers are:
cyl #1-150psi
cyl #3-150psi
cyl #5-160psi
cyl #2-147psi
cyl #4-156psi
cyl #6-146psi

Specs:
8.7 c/r, 216/219 roller cam, cnc series Champion iron heads, 124lb injectors, 6466BB
These plugs are not uniform
What afr are you running
Have you verified pump pressure on both your alky pumps and intake pumps?.
Also your plug choice should be a non projectile plug.
Your not on an optimum plug for pump gas alky.
 

longbedGTs

high on gas fumes
No, injectors haven't been flowed. Guess that's a must being that they went from running E85 to pump gas, huh?
AFR dips into the high 10s and o2 volts are in the 840 range.
Haven't verified pump pressure, and the alky pump was replaced in 2016.
What plug and gap would you recommend?
 

longbedGTs

high on gas fumes
Interesting post from Lonnie about the distribution of alky vs g-forces under acceleration. Not that I'm running anywhere near the big HP guys, but this theory may have something to do with the problem I'm experiencing.

The long story short Methanol has a specific weight and when the car would accelerate the g-force of the acceleration would plant more of the volume of the alky to the rear of the intake causing the front two cylinders to go lean.

 

RichieRocket

New Member
Swap a plug wire with number 1 and look at the plug that you swapped it to after a few miles if there is one that will reach. It looks like it could be as simple as a weak spark. That’s where I would start because it’s free and quick to check, then dive deeper.. good luck
 

longbedGTs

high on gas fumes
The plug was tight in the head, but now that you mention it, I do see that the threads look "dry" compared to all the other plugs. Is that what you're talking about by having that look? I'll swap plug wires and see what happens. Forgot to mention, this has a TR6.
Another thought...is it possible to put the RJC power plate up side down? Maybe I did that... This really seems like a problem with alky distributing to cyl #1. Having the dual nozzles, perhaps there's too much alky spraying which isn't allowing it to atomize properly before reaching cyl #1? (as mentioned by Lonnie in the thread linked to in post #12) Maybe it needs to be turned down. Just thinking out loud.
 

Chuck Leeper

Toxic old bastard
Staff member
Stock rail/regulator?
Without a closeup of the ground electrode, and a look at the fuel ring on the base of the porcelain, kind of hard to tell.
Note that only #1 has the threads dry.
Are you using antiseize?
As mentioned, do the checks suggested, get a set of non-projected plugs.
Start over and don't put a lot idle and drive time on them prior to a read.
 

longbedGTs

high on gas fumes
It has Champion rails with 8an feed from the tank, and an Aeromotive 13129 regulator. Hellcat 525 pump. No antiseize. Ok, I'll get some non projected plugs(never heard of this term until now). Thanks!
 

dynoman

Well-Known Member
Does your car have iron heads ? If so I ran NGK BR6FS ( 4323 ) in my iron head E85 motor , so a little hotter plug would be a BR5FS ( 4123 ) both are non-projected tip plugs and the number denotes heat range . Stay away from non-resistor plugs with stock ECU . Ask Mr Spool what plugs he used , he ran ALOT of alky .
 

hensleyt

Well-Known Member
I was thinking the same as you about the plugs. was this ,I think ill check the plugs our was this after a 10 second pass?
I agree time for a set of plugs. why a two nozzle? Cant see the ground strap,I don't run a plug that cold of a number, but I no nothing about this car.
Stock rail/regulator?
Without a closeup of the ground electrode, and a look at the fuel ring on the base of the porcelain, kind of hard to tell.
Note that only #1 has the threads dry.
Are you using antiseize?
As mentioned, do the checks suggested, get a set of non-projected plugs.
Start over and don't put a lot idle and drive time on them prior to a read.
 
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