i was driving on monday to my parents house and all of a sudden, about 2 miles after i exited the highway, my engine started knocking wicked loud. i thought maybve a valve was ticking extra loud or maybe i broke a valve spring. i continued driving about another 6-8 miles to my brothers house, without any power loss or overheating. upon arrival, i popped the hood, and realized just how loud it was. the two of us couldnt be sure what it was, so tuesday i called up a friend who knows more.

we removed the valve cover. everything on top seemed to be in proper working order.

it doesnt knock during startup, but as soon as its up to idle speed, it knocks real loud. literally sounds like someone is hammering on the motor. while two of us were listening trying to think of what may be wrong, we had to yell to talk over the knocking.

knock increases as the rpm's climb

knock appears to be coming from the front of the motor, but upon inspection of the timing chain guides throiugh the valve cover, there doesnt seem to be a problem there.

my buddy suggested it may be a spun bearing, but between not being entirely sure what that means, and the fact that that is how he diagnosed the problem, im looking for advice.

what might it be? if i brought it to a shop, what would they likely charge to determine the issue? any thoughts?