Engine Temps: What is acceptable?

[scott7556]

Just rebuilt my trusty 400. Jetted properly, K&N filter, Pro Circuit pipe, Wiseco 10:1 85.5mm piston, White Bros rev box. What engine temp range should I be in? And where should I measure, I know they have temp dipsticks, but I would really like to use the infrared heatgun. It just feels like it runs hotter now, could just be me fearing the worst as this is my first engine rebuild. Thanks fellas!

[CarGuy7a]

well higher compression will run a little hotter.

i have the oil temp stick on mine and the oil temp runs anywhere from 200 to 300 degrees on a 90 degree summer day.

and it runs 100 to 200 on a winter day around 30 or 40 degrees.

anyone know what the "danger zone" would be for the engine running way too hot and you start losing your reliablilty or parts start malfunctioning/break/wear unusual?

[scott7556]

My findings are as follows for a simple test:
Last night warmed my quad up, it was in the garage and about 55 degrees.
I aimed the infrared gun at the head gasket on the left side of the quad and my temp steadied out at around 225 degrees. The headpipe as it mated to the motor was as hot as the upper 600's though, and the very tip of the exhaust was in the 85-90 range. The rocker arm holder/cover was in the 140 range. I know that this is not a real world test becuase I was not moving, but I don't think I am on the verge of melting down, am I?
Thanks!