Here are some photos of the Geo Metro engine. I am using a Raven ULT redrive and stock Geo throttle body fuel injection from a 95 Metro. The fuel pump and filter are from a 960 Volvo. I made the thermostat housing by welding part of the stock Metro thermostat housing to a piece of aluminium pipe. The cooling bypass circuit is completed by welding a bung to the pipe and routing water through the intake manifold to the water pump inlet. Testing to date has been limited but so far the thermostat appears to work well. I will try running the engine with prop before I braze the cooling fins in the radiator.
Left hand view showing louvers.
Left hand engine compartment.
Right hand engine compartment.
Closeup of the thermostat housing.