An internal combustion engine is a crazy inefficient thing. Modern, direct-injected, gas engines have a peak efficiency around 30%. That means that, at best, about engine power is warming air through the radiator and about engine power is warming air as waste heat in the exhaust! One might think that something so incredibly inefficient could never find market acceptance. However, like the old incandescent lightbulb (with an even worse efficiency!), it works so well that we don't notice the terrible waste.
Knowing this as an engineer, and also having been warned by Jim Renesis MGB Build Thread , I bought a 300hp capable radiator. Then I had to find somewhere to put it!
I managed to find a radiator that would fit at an angle. The was appropriate as the RX8 radiator also sat at an angle, although the other direction. I was pretty happy with the mounts/air blocks that force the air through the radiator.
That all looked great but when I finally got her started, the radiator passage on the passenger side got hot as hell and the driver side was cool to the touch. Hmmm. Fortunately, I had invited Larry, our ace technician from work to check my wiring and he quickly identified that there was no baffle on the passenger side. That is used to force coolant through the top of the core and back through the bottom. I'm sure I could have eventually gotten a proper radiator from Griffin but I didn't have that kind of time! So I milled some slots and asked Larry to apply his TIG welding skills.
That worked out! BB runs at a much lower temperature now. She used to regularly get up to 220F but now the max she sees is 195F. Even during an autocross, where the old engine and radiator went crazy, she is rock solid!
I know this because I took great care to machine the fitting above which puts the antique temperature bulb in the stream of coolant exiting the engine. So, my 55 year old temperature gauge works perfectly!
There was a challenge with a radiator hose that exited directly to the passenger side. Here I made a 90 degree fitting with an O-ring for the engine block side and hose fitting for the radiator side. That was a neat bit of turning as you can see below. I had to offset the four-jaw chuck which looks very strange as it's spinning but made a nice part!
I also turned and milled a fitting to connect the heater.
I've been afraid to try that yet but Fall is here so it will get road tested soon!
So, no matter how poor the efficiency, the combustion engine has brought us a long way. Electric powertrains may be the future (and have an overall efficiency around 75%) but this legacy is worth some effort to preserve!
Stay cool and keep on having #funwithcars !
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