gus310

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?

My814x4

Sounds like you have a rod knocking , remove the oil pan and check the rod bearings you will probably see bearing pieces in the bottom of the oil pan. Yes they will charge you to inspect and or diagnois an issue.

lonestar

I bought an 87 rnnr from auction and chased a knock around the motor until everything was done except a lower end rebuild. How many miles do you have/how well has it been taken care of... two ?s you have to answer yourself.
Just because you don't find junk in the pan, doesn't mean their isn't any...
That is the best place to start.
Mine was connecting rod bearings$$$but you can always tear it apart yourself and have someone else machine and short block it.
thats a long road, good luck

LONESTAR

DeathCougar

iTrader: (23)

Most common is #3 and #4 rod bearings on these engines. If anything goes out, its usually these bearings.