Chevrolet Repair: 1986 Chevy Celebrity Eurosport 2.8 FI, crankshaft damper pulley, loose bolt

Question
I have a 1986 Chevrolet Celebrity Eurosport 2.8 FI engine with 150000 miles. Last night I noticed a metal sounding knocking noise from under the hood. I noticed that the noise was coming from the timing chain area.  Upon close examination of the engine, I could see that the wheel attached to the crankshaft (that has the timing marks) appeared to be turning out-of-round. I shut the engine off and I could see a 1 inch “rub” mark on a section the wheel. Advice from non-mechanical coworkers has suggested that it is the main bearing, the oil seal, the timing chain, etc.  I am not willing to start the car for fear of increasing the damage. What do you think it could be? Can this be repaired for less than the car is worth? Can the repair be done without removing the engine from the car? My wife refuses to get rid of the car and would like me to get it fixed (if possible). Any help would be appreciated.

Answer
Hi Jeff,
Good find!!
That sounds like the crankshaft damper pulley is loose.
Probably not the main bearing or seal. Probably just a loose bolt that holds that pulley on.
Remove all accessory drive belts that are turned by that pulley, and then see if you can just pull it off, or if the bolt is still partly holding it.
Hopefully you can just tighten up the bolt.
I would probably try to remove it just to make sure the seal, and contact surfaces are good, and check the woodriff key that fits in the grooves.

Van