Engine knock

[doonjumper]

I have a 383 stroker with about 6000 miles on it and it has had a knock for about a 9 months now. It is in the pan area. It has 35-40 oil psi @ idle @ 190 temp. It has 60-65 lbs oil psi at 3000 rpm @ 190 temp. The knock is more prevalent at start up and tends to fade when it reaches 190 temp but you can still hear it just not as much. It has a total timing of 36 degrees. I did clearance the block when initially built to accommodate the rods because it is a stroker. I am pretty sure the knock is in the pan. I am thinking about pulling the pan and inspecting. Do you think that I should go ahead and changed the bearings since I have the pan off if I don't see anything obvious upon inspection? Do you have any other avenue's you think I should check out? Keep in mind the knock has not always been there. Started over the last 100 miles or so. Thanks in advance!!!

 

[Hogback Fabrication]

Probably a rod knock. Drop the pan, check the bearings.

You'll find the problem.

 

[Mudstud]

Probably a rod, maybe a wrist pin?

 

[doonjumper]

Ok I pulled a few rod caps and those looked good so I pulled rear main and the bearings had signes of wear. they were scratched up and had metal shavings embeded into them. I started pulling the rest of caps in order trom rear to front. The bearings increasingly got better as I reached the front. Now.......after I took off the front main I looked at the timing chain from the rear. I put a screw driver against the chain and I was able to move it about 3/4" to 1 " from side to side.

 

[Mudstud]

The wear on the bearings is likely your noise. Is the crank gouged on those journals? I don;t think the timing set should move at all but someone else needs to chime in on that.

 

[doonjumper]

The wear on the bearings is likely your noise. Is the crank gouged on those journals? I don;t think the timing set should move at all but someone else needs to chime in on that.

There are a few minimal grooves/ in the journal. You can barely feel them. The oil pressure was normal so I'm hoping that I can get away without having to resurface the crank.

 

[4X4HIGH]

Get a pry bar and somehow to try see if you can get the crank to move forward and then rearward and by how much. I'm betting you lost the thrust on the crank and that would account for the rear bearing being the worse since that is the thrust bearing. If this is the case there are several reasons why you can lose a thrust. A bad engine ground, a balloned torque convertor, a pinched tranny line, or a plugged tranny cooler. If by chance the tranny is a manual then it can happen from a misadjusted clutch, or resting your foot slightly on the clutch pedal or if it is a centerforce clutch those are notorious for causing thrust problems in the engine.

 

[Mudstud]

So you are saying that the rear bearings of the crank take the most abuse in a clutch driven vehicle? I don't get how any of the other possibilities you mentioned would have anything to do with crank bearings. Care to elaborate?