spot on, we can really only guess bevcouse each engine with its own individual setup will be a little different.

what i can tell you from personal experience, with a 3 litre (though mines bored not stroked) is that i ve found the hotter the better (as long as your head doesnt warp and this doesnt effect the air intake temps)

as on a previous post my engine put out its best figures at 210 degrees.

what you have to watch is that the heat soak created by this temp can warm your intake temp especially at traffic lights, so its a trade off. if you are consantly moving (like on a track) than you want to run hotter, though if your a traffic light drag artist than a little cooler so your intake temps arent effected as much.

I haven't checked Pegasus and others for the infared pyrometer prices, but yesterday I was in a restaurant supply house and looked up on the rack and there hung an infared pyrometer for $24.99.

steve77

Hotter engine= more complete burn = more power.

But...

Hotter engine = more stress on the oil & alloys.

In stock trim, the L engine produces the most power around the 200F mark (~95C).

I run a 180F (82C) in all my engines, as they are turbocharged & the cooling system tends to get stressed more with the extra thermal load of the turbo (and the chamber temps can be up to 100% higher).

Coolant temperature is very important, so is oil temperature. For any serious engine I highly recommend a thermostatically controlled oil cooler & oil temperature guage. Racing an engine with oil temperatures below about 70C is not a healthy thing.

I generally see my oil temps hovering around the 85C mark with coolant around the 90C mark. An interesting thing is that it takes about 4km of 60km/h driving for the engine coolant to be at operating temperature, but about 15km before the oil gets thouroughly warmed.