Originally Posted by Air Randy
Do a simple compression test on all 6 cylinders, that will give you a much better idea if you need a total rebuild or just a valve job. If the other 5 cylinders are all within 10% of each other and not too low compared to the factory spec (be sure and adjust for the elevation difference:actual reading divided by .86) you can probably get by without a full rebuild. 0 compression on 1 cylinder could be a blown head gasket, a burnt valce or a cracked valve seat. All are fixed by pulling the head as the first step.
If the engine isn't burning oil in addition to the #2 cylinder issue you probably should just do the valve job.
I am not a big fan of installing used engines unless you are totally desperate or unless you know the engine's real history. Otherwise you could go to a lot of effort to install something that could start giving you a lot of trouble right away.
I did a compression test on all 6. The motor was cold since I didn't want to run the motor to get it to operating temp. The other 5 had compression that were just OK. One had a zero reading (tried 3 times). No burning of motor oil that I can see. To be honest I have only put 100 miles or so on it since the last change, but 70 of those were hard miles on Moab trails.
I pulled the valve cover, but didn't see anything (untrained eye though). I guess the next step is to pull the head. Then it will be a paperweight so I am not excited about that.