An 85 Jeep Cherokee 2.8 l V6 185k miles. Noticed that the outer ring of the harmonic damper was free wheeling around the center flywheel hub. Had it cut off and only intend to run the vehicle for a month or so (cash for clunkers). Speeds limited to 45 mph, occasional short sprints to 55. What is the risk? Should I get this replaced even for such a short period? I do need the vehicle in the meantime. Obviously cannot do timing.
Im surprised you could still bolt the bottom pully to the end of the crankshaft. usually that dampner has the pully attached to it. you got the fan belt back on??Maybe Im not understanding this???
Running an engine without a harmonic balance can lead to a crankshaft breaking in half, even after you’ve fixed the harmonic balance.
A straight 6 crank would be FAR more vulnerable to breakage then the short, rigid V6…You might get away with it. Maximum stress will occur at some point of resonance under heavy load…Just be gentle with it as you nurse the last few miles out of her…
Not all cranks are created equal 
You mentioned an inverse relationship between length and strength. But longer cranks may often be forged versus a cast crank. I wouldn’t place any bets on that V6 crank being all that more robust because it is short. On a side note, I knew a guy who thought he could get away without a balancer on a marine 350. Broke 3 cranks before it sunk in. The last one broke the same day.
In this case, we don’t know how long the outer ring has been loose. It could let go any time…
Marine engines work very hard…
Only the outer, free wheeling, ring was removed. Lower pulley is attached to center of assembly. Did not have to remove belts.
Yeah, it was funny at first. We had a bet pool going on how long it would go before the inevitable. A car engine practically falls out compared to an inboard boat engine. What a royal PITA. The last time, we felt sorry for him because he was basically perched on the ledge and had to be talked down. But you know what they say- you can lead a horse to water…
Personally, I get a junkyard balancer before I’d run around with it messed up. Things don’t always go as planned. The OP may need to keep the vehicle longer than expected and then there’s the issue of sudden and complete failure. It’s almost impossible to avoid an occasional romp (like an entrance ramp) and what kind of stresses were encountered before the damage was found? It could fail any time even if babied now IMO.