Hey guys, appreciate any help. It's an '83 CJ7 w/ the 258 inline 6, Carter BBD carb, 5 speed manual (T-5?), Dana 300 t-case, 4.5" suspension lift, 35" tires (re-geared.)
I've wanted a project CJ for a long time now, and found one not too long ago. Was in decent shape for a 30+ year old Jeep, but I felt like I could tackle fixing it up myself.
When I bought it, I could tell the brakes were shot. No problem, got those fixed up no problem. New pads, master cylinder, hoses, etc. Now I won't kill people. Had a hell of a time starting and keeping idle, so I rebuilt the carb. That was easy-ish, and it ran 100x better.
Crapped out on me once with no spark. Turned out to be the computer. Replaced that with an old spare, and all was well. Did an oil change a while later and noticed the old oil smelled like gasoline pretty bad. Ah crap. Compression check is way low in one cylinder. I don't have the space/equipment/knowledge do to a full overhaul.
I get a mechanic to do a rebuild and over-bore. That turned out awesome, engine ran like a dream. Couple weeks later it decides to boil over the radiator. Turns out the thermostat (which was brand new w/ the rebuild) didn't work and it overheated. So that was replaced and the overheating stopped. Figured all was well!
Well, eventually it starts having a gradual misfire... can hear and feel it missing. That gets worse and worse, keep going back and forth with the mechanic and they're blaming it on the carb. I take it back, they adjust the carb and call it good. This help a little, but obviously doesn't fix it.
Eventually I decide to pull the plugs and look. Two of the plugs are just about completely fouled in shiny black carbon looking stuff. (See third pic.) Not wet that I could tell, but shiny. Two plugs looked perfect with a light brown color. Other two plugs are slightly fouled, but not as bad as the first two.
I replaced the plugs and plug wires. Runs great again! Problem is, it keeps fouling the same plugs over and over. Mechanic is still trying to play it off as carb / newly-rebuilt issues.
So what do you guys think, is it something like bad piston rings, bad valve seals, etc. or something simple like a bad distributor or the like? Kinda hesitant to go back to the mechanic as they couldn't even diagnose fouled plugs... but I'm not tearing it down and voiding my warranty.
Other than that, it's really fun! Kinda knew what I was getting into when I got a project CJ, but it's turned out worse than I though, haha. Ah well, I still love it.