Ford Repair: 302 ford motor, rod bearings, cj 7

Question
I have a 1986 CJ 7 Jeep that has a 302.I have a knocking sound in the front of the motor. At first I thought it was my oil pump going bad, not pumping enough oil. I replaced the oil pump with no results. I have also replaced the harmonic balancer. I noticed that the bottom pully is going in and out when the motor is running. I took a pry bar and pull in behind the pully and it come out approximately 1/2 to 3/4 inch, and I know thats not right. So what could it be. Crakeshaft problems, harmonic balancer loose. I'm lost, can you help me. Thanks

Answer
Larry, I have got to say that the outcome of your situation will probably not be good.  The first thing that came to mind when I read your question was that you had spun a rod or main bearing.  More than likely a main.  When you pry on the pulley, are you simply pulling the pulley away from the balancer? (which would represent missing bolts in the pulley, there should be four)  Are you pulling the balancer away from the spacer on the crank? (which could represent improper installation of you new balancer) Or are you actually moving the crank? (A variety of things, most not good)  If I were you, I would remove the timing cover and take a look at the crank key, make sure that everything is in place.  If everything looks good in the front of the motor, then I would remove the oil pan and do a thorough inspection of the crank.  Look for burned areas around the mains and around the rods.  Look for loose rod bearings.  Do not use anything metal to do this inspection.  Hands only.  Push up and down on the crank and check for movement.  That is the best advice I can give you on the pulley moving in and out.  I will say that you must find out why that is happening before you use the engine anymore.  You may be taking a chance on doing even more damage with an unbalanced lower end.  Now, assuming that the knocking is not coming from the crankshaft, the only other thing I can say is that pre-detonation can cause a tremendous amount of knocking.  If you have been running something else that stock spark plugs, now would be a good time to switch back, at least for the time being.  I hope I have helped a little.  I am interested in your situation.  Please keep me informed, as I would like to know the outcome.  And please feel free to ask me anything else, or follow up on what I have said.  Good luck,  Jason