Chrysler Repair: broken Valve Spring, jeep grand cherokee, broken spring

Question
I own a 1997 Jeep Grand Cherokee Orvis on which a valve spring has broken. Is there a way of replacing the spring without haveing the head off and what damage if any could of been caused to the engine. When it broke the engine run like a pig and was only running on 5 cylinders, it was driven like this for approximatly 3miles

Answer
Hi Steve,
If the valve was not damaged such that it won't seal, I have heard of replacing the spring by setting the crankshaft in such a position that both valves for the bad cylinder are on the lowest point of the cam (e.g. closed) and then applying pressure with an air compressor thru the spark plug hole so as to maintain the valve with the broken spring in the closed position, and then remove the old spring and put in a new one with the compressor running all the time. So I would explore that with a mechanic to see if he agrees to give it a try. I suspect the valve is the only part that has been potentially damaged. But my experience with this sort of history is limitied. At least you have an alternative approach to removing the head to explore with mechanics in your area.
Roland