I need some help sorting out my 13B engine over heating. It started this spring at CMP where I over heated and lost a engine, since then I have rebuilt the engine, but I still have a heat problem at high rpm's. I originally thought it was my water cooling system, but everything there appears okay. I am now wondering if it's not the oil cooler and the water temp can't cool the engine as fast as the oil temp increases. Normally water temp was running at 160 to 170 degrees, now it will go over 200 if I don't shut down and oil temp will run 20 degrees hotter than water temp.

In addition oil pressure was over 100psi at high rpms but latest attemp to run this engine the best I can get is 40psi and at idle maybe 15psi. can the heat cause problems with the pressure relief valve?

What else should I check that could be causing over heating?