Rod bearing problems

I have an engine that has burned up rod 5 and 6, rod 6 was kicked out of the block. The main bearings and the other rod bearings looks perfect. The engine did not detonate and have been running strong since build. The bearings and rods have 27 passes on them in an NA engine so what happened ??


PLEASE HELP !!!

I have several photos

Thanks ITA

 

more info

The engine is a single carb wedge mopar with a keith black block and crank. The piston rings rotate freely and the ring side clearance are the same as when the engine was assembled, so the pistons are ok.

The spark plugs was changed to hits ago and both new and old look ok, no detonation.

The engine has 27 runs under the belt with no problems so something have changed....

Thanks ITA

 

How much oil you running? Years ago we had a bunch of rod failures due to a spun bearing on #6. I think it was Steve Faria that told us it was lack of oil. Said for some reason it picks on #6 if it starves for oil. At that point we were only running 14 qts. Put an extra 3 or 4 in there and problem solved.

 

oil pan/pump

We are running 8 qts in a wet sump with a keith black pump. We ran this setup last year with no problems BUT NOT with the keith black pump.

 

with the KB pump you ran probebly with an almost empty oilpan, i would put in at least
16 qt in the oilpan to be safe.

 

8 quarts..that is no oil we run twice that much..put more oil in it.Dave

 

Yikes. I bet if you double the oil in there your issue should go away. By the time you do the burnout, back up, bring RPM up at the line, you've got zero left in the pan.