There are a number of facters to consider here. If you listen to your engine guy, he's worried about heat in the intake manifold. I havn't worked with a BB Lima motor in so long, I'm not sure about that. It's an interesting theory, though. Everyone knows that cooler air makes more power.
A few well designed studies have shown that coolant temps below 160* will cause increase cylinder wall wear. But that means you'll only get 100K miles instead of 150K.
Oil should definatly be hotter than 160*, and probably closer to 200*.
Oil temp tends to be pretty close to water temp.
As said above, the thermostat only controls minimum temperature, not max or operating temp. As the rpm's and ambient temps rise, so will the coolant temps.
The fan should not run all the time. There's no need and no point. The turn off point should be 5-10* cooler than the turn on point. With a 160* thermostat, I'd have it come on at 170, off at 165.
Dependin on the fan, it only moves air at about 30-40mph. If you're traveling at 50mph, you're moving more air through the core than the fan will. Put an over ride switch in the dash so you can turn the fan off while traveling down the highway.
I think it would be a struggle to keep a BB at 160* on a warm day in traffic. A by product of HP is heat. More HP = more heat. In the winter on the highway, I think it will be a struggle to get it above 180*. But, that's the whole point of a thermostat and a huge radiator - aiming for stability.
Here's what I would do. Use a 180* thermostat for the coolant. Use a 195/185* fan switch. To address the original intake manifold issue, I would have the bottom of the manifold ceramic coated to block heat transfer. But leave the top alone, or simply painted. You want any excess heat to dissapate through the top. Drive it around for a while. If it gets too hot, then change the thermostat and fan switch.
Hybrid Mode
