Unresolved Printer keeps jaming

The printer was working well. But at 24 hours into a very long print it chewed up the filament. Now, it won't run more than 10 minutes without jamming. The first thing I suspected was the cooling fan on the hot end. It isn't the original and the shroud is a bit loose. But it continues to eat up the filament even if the fan appears to be mounted correctly. So I don't think that is it. The Z offset appears to be good. It was .3 too high - first layer was always .3mm thicker, but I fixed that.
I started out with the default settings in Simplify3D. Changed the temperature to 198/50 which works good with the PLA filament that I am using. Set first layer thickness at 200%. The speed was 60. It ran for 24 hours at that speed. I tried dropping to 50, raised and lowered the temperature. Even took it to the max - 280C. Also tried different PLA. But it continues to eat the filament.

Any ideas what could be wrong here?

This is an R1 with the hexagon heat end.

 

Are you using an oiler?

Your hobbed bolt might be loaded with filament at this point too so it may be wort it to take it apart.