it us the valves. but can't a rod knock develop from oil starvation?

 

Well it was definitely rod knock. I pulled the engine and tore it down this past weekend. Cylinder 4 rod bearing was completely spun out. The two of them were stacked on top of each other and stuck on the crank.

 

That sucks but at least you got it and stopped driving it before it launched a rod through the block. Are you still going to rebuild the motor or are you leaning more towards a drop-in replacement? I'd imagine there is a good chance that the crank is junk now too as a result of the spun bearing causing it to exceed runout measurements.

 

Yeah definitely glad the rod didn't let go. I am planning to rebuild it myself, I didn't want to buy a used motor and deal with oil consumption and a new motor with 0 miles would be more than it costs to build it. Plus, this way if I ever decided to go with a vortech in the future, the bottom end will already be built. And yes the crank was junk. That lobe was out of round and would have needed to be machined .030" under. And there was some slight discoloration from the excess heat