Thanks for those photos Machaca, I assume that the oil passes through the capillary pipes & the fuel passes over them?.
I wonder if the oil is pumped through on a constant flow basis, or is there a mechanism for the oil to be pumped through intermittently to keep engine oil temperature within specified limits?
If the latter stationary oil in the FCOC would reach fuel temperature, would oil viscosity be OK at this temperature?, if this was the case no fuel heating would occur.
Thanks again for the excellent photos.