Mystery Engine Knock

Okay so here is another update:
Engine completely disassembled and we discovered that all the bearings and the crank had been scored along with some of the cylinders and pistons. Mains are OK. Cause is oil not getting to those plays but the passages are all free and the pump appears to work well but needs to be taken apart for sure. One thought that I hope somebody can answer is about my oil pan. I have the first design oil pan with the screw in dipper tray - is this dipper tray lower than a regular pan? That would cause no oil to come to the bearings.
 
Chris,

It seems like you may have found your problem. You may be able to use a borescope to see if the dippers are reaching far enough into the tray. You can knock the breather tube out of the engine. It is a tight fit.

It is normal to have 1/8 inch front to back clearance between the big end rod bearings and the rod journals. A bent rod will push the big end of the rod back and forth and bang into the journal shoulders. The geometry is not obvious. A straight rod will just stay in one place even with the clearance. The only reference I could find that mentioned the back and forth movement of the rod if bent is https://www.mtfca.com/discus/messages/708324/773693.html?1500638368.
 
Is it possible that you’re intake and exhaust manifold and intake are not machine correct as no makings a good seal hence hard starting noise and poor running
 
Yes the dippers were facing the right way.

I think I am on to the cause of why this happened, need some more research!
 
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