Having trouble reading this spark plug.
What do you guys think?
looks like you're running too rich with a hot plug. also when you replace your plugs you need to gap with feeler gauges not one of the circle tools. only thing those are good for is gapping your ass.
>Late model BBC valve cover and accessory drive
Anyway that plug was below self-cleaning temp when the engine was stopped. Why is another matter. It was probably just idled into the shop or something and colored the plug that way. To read plugs for WOT mixtures the engine has to be run WOT and cut clean, no idling. And you have to look down into the area between the shell and porcelain with a light and magnifying glass in order to see anything.
Needless to say this is a pita so I just tune for either acceleration rate, say a 30-50 mph pull. Or with a wide band while keeping in mind the acceleration rate is what you're after, not the theoretical good ratio. After that what you can look at the pugs for is porcelain condition (too hot spotting, detonation damage etc) and the timing line on the ground electrode.
ok that explains a bit. carbs are generally tuned for what you run them at so say you want 11.8 AFR (wideband reading) at 4k rpm where all your power is then its going to optimum in that range. at idle it's going to pump rich plus you won't have the cylinder temp to clean like >>14206427 said. Get a WOT run and pull a front or rear cylinder plug on either side as they run the leanest average.
its the angle it's clocked at. you can buy plug clocking spacers for people that make enough power to blow out your spark.
when did the problems start? did you change anything? what did the plug wires Ohm at? you haven't fiddled with the idle mixture screws have you?
That's why I said it wasn't up to temp. The plug was getting washed by the incoming air-fuel mix which cooled that side off enough to leave a deposit but it's not so rich as to foul the whole thing out
112 ohms. In spec. Started today while out on the street. Started to hear a weird idle then when I gave it gas you could hear the misfire. Engine has 2k miles. No problems till today
if your ignition system is up to par then I would check compression and leakdown since it's a rebuilt engine. especially if you had the machine shop do the bottom end. not only that it's free to do.
You've got alot of people on here who have no clue how to read a plug answering you. Your two pictures are of no use, you need to show us a good picture of the strap. Only then will we be able to make any useful assumptions about how your motor is running.
Line em all up next to each other and get a good shot of the ground strap from above and a little toward the strap side. Make sure there is plenty of light on the strap and that the pic shows down in around the ceramic as much as possible.