Man oh man.. that really sucks. But 4hrs and you were running for that long?? What kind of clearances are you running on the bearings? You should have more psi at wot.. more like 60psi. What weight oil are you running? I am runing a 15w/40 synthetic and see 60/70 when cold and 60 when hot.. it does go lower when it is hot but usually to about 40 at an idle...
I hope it isnt serious.. and having more time this winter you can take your time and find out what happened and make it right..
Good luck and dont give up.. when it does run, you will forget the grief!!