I decided to try some new spark plugs in my 300hp crate 360 magnum.
I was running the NgK v-power zfr5f11’s, I swapped them out for the Ngk v-power bkr5e plugs because the bkr5e has a shorter insulator on it andnive read the magnums run a little better with the shorter insulated plugs.
Anyways I pull all the plugs and they all look pretty good but cylinder 8’s plug is a little darker then the other 7.
I took a picture of the difference in it compared to the other 7.
What could be causing this?
The plug on the left is what the other 7 plugs look like.
The plug on the right is what came from cylinder 8 and looks to be firing different from the others.
I haven’t done a compression test in awhile but last time I did one all 8 cylinders were dead on at 150 psi and that was done with the engine fully warmed up at 190 degrees and at an elevation of 4200 feet above sea level.
It’s too late to perform a compression test on it tonight but I am going to check cylinder 8s compression tomorrow after work with the engine warm.
Just thought I’d share this to get some input and opinions.