Bryan, not enough fuel will do exactly what you describe. If your EGT’s are in the low 1200’s then fuel rate is NOT likely your problem. Just to put the affect of fuel rate into perspective.  I live in Arizona and the OAT was 110 degF a few weeks ago when this happened. 2500 RPM and 30 inHG (turbo normalized). I was at low altitude and low airspeed as I was over the top of my airport, circling to land.  I inadvertently set fuel mixture in the “max power/ max temp” range.  In 54 seconds my CHT’s went from 380 to 408 deg F.  I caught the JPI flashing at me and immediately went full rich.  48 seconds later my CHT’s were at 380 degF.  (From JPI download data) Oil temp will follow CHT. A bad oil cooler will also cause this problem as the oil provides a significant part of your metal cooling.

Craig Berland

 Anybody have any ideas or advice for the following situation:
 
 Lancair 360 with carbed 360 (180hp) engine. 475 hours on it about. Chrome
 Cylinders. I have a Plenum cooling system and larger cowling inlets.
 (Zavatson's cowling and plenum system)
 Oil cooler is mounted at the front inlet.
 Oil wont cool in climb and will go up to 230 and probably higher if not
 stabilized. CHT's are all hot in climbs and will go to 440 no problem. Cant
 figure it out.
 Motor runs great, compression good, boroscoped fine, mag timing good. All
 leaks in plenum or baffling are sealed.
 Probes were checked out ok.
 
 Only thing I haven't checked is the vernotherm.
 
 Thanks for any advice.
 Bryan