jarromcmillian

Hello all, this is my first post in here, so take it easy on me! I bought a 1986 XJ 2.5L 4x4 off of a kid in Oklahoma City a few weeks back for $550. Now this is my first Jeep, so it's a bit of a learning curve, I frequent the VW world. It's all stock, ex oil field truck, usually dents and dings and rough interior, but will make a great trail truck when I'm done with it.

Anyway, the kid bought it not running from the previous owner, said he overheated it and now it won't run, cranks good but no start. Him and his dad removed and replaced the pistons, rings, honed the cylinders, water pump, rod bearings, crank bearings, CPS and the various gaskets pretaining to those jobs. He didn't however, replace the timing chain, for whatever reason...this motor has 236,000 miles, give or take a few, should be a common sense thing.

Since I bought it, I replaced the plugs, wires, cap, rotor, battery, fuel filter and the defective ICM and I have checked every sensor that is on this engine that I have perameters for, all check good. Now, she has fuel, spark and everything is timed right, triple checked, been working on this every afternoon since I bought it, could do the timing in my sleep! Tried changing the ignition 180 out, still nothing. Did a compression test, cylinders 1, 2, and 4 were a big fat ZERO! Cylinder 3 would get up to about 30 psi. I squirted a bit of oil in each cylinder, no change, number 3 went up to 32-33 psi or so. I figured, having so many miles, maybe the timing chain jumped a tooth or is just wore out and has shifted a bit, so I disassemble the front of the motor and get to the chain, so loose you can jump rope with it and the tensioner is fully extended and has grooves as deep as the Grand Canyon on it. So now I need to replace it, no big deal.

Me being dumb, I dropped the piece I was using to find true TDC into the cylinder, so now the head is off so I could retrieve said piece. Cylinders look decent enough, I filled each one with oil to make sure the rings hold, so far so good, check that again tomorrow afternoon after work.

My question is, would the timing being off just a bit cause no compression at all, or could there possibly be an underlying problem? I checked out the head and it looks decent enough, probably strip it down and take it to a machine shop and have it cleaned, decked for true and have the valve seats reground, replace all the spring and valves with new parts and do a little porting and polishing, get a little extra oomph out of her. I'm just at a loss for now, been on this for 3 weeks or so and not making any headway and getting frustrated. I know I can only do so much until I actually get the motor back together as well, so it's whatever I can do for now.

Sorry for the long post, but I have learned in these forums, the more info the better, saves on questions! Any info you can afford to me would be great, I'm to the point of pulling my hair out, what little is left anyway!
Thanks for any help in advanced!