Re. my discussion of how much cooling you get out of an oil cooler. I’ve had some years to think about those experiments and I think a clarification is necessary. When I put a temp sensor before and after the big oil cooler I did get up to 14deg of delta between the two sensors, but it would not be accurate to say “that’s 14deg of cooling”.
Here’s what I think was happening. Our engine is not designed to dump heat into the oil. The water jacket surrounds the cylinders and combustion chambers, there is no oil-jacket sort of thing. Also, oil isn’t as good of a heat xfer medium as water is. This sums up to oil being slow to warm up, slow to cool down, and not moving a helova lot of heat in the process.
So imagine a scenario where the oil is flowing into the oil cooler at 220deg and flowing out at 206deg…a 14deg delta is reached and the engine seems to have a steady state oil temp of 220deg. Lets say the oil cooler is dumping 100btu/min. I pulled that number out of my butt, I have no idea what it really is.
Then remove the oil cooler. Now the oil temp starts to get really hot because that 100btu/min of heat loss is what was keeping the oil temp at 220deg. As a result the oil temp goes higher and higher, ultimately reaching 250deg.
So on the one hand it’s accurate to say that my big oil cooler was worth 14deg of cooling, but on the other hand in the absence of the oil cooler the oil can get pretty darn hot if there isn’t some means to cool it.
My later experiments looked at how much cooling I could get if I had air blasting on the oil pan. I found that if I had no oil cooler and my skidplate blocked air flow from the oil pan that my oil would hit 250deg during a hot session. So altho the big oil cooler did create only a 14deg temp delta across it, the oil cooler was also responsible for a drop in steady state oil temp of ~45deg.