adding an upper thermostat to a Honda D15 engine?

[GasSavers_Erik]

I have an 87 civic with a D15a2. My motor has the thermostat located in the lower radiator hose and I believe most D15 motors are this way. Since there is no thermostat in the upper end of the engine, coolant travel through the cylinder head outlet to the top tank of the radiator is unimpeded.

My engine warm up times are quite long. I feel that this might be because of convection currents moving hot coolant from the cylinder head up to the top tank of the radiator and then cold coolant from the top tank of the radiator falling down into the engine to replace where the hot coolant was.

I am wondering if the warm up time could be shortened by either installing a second thermostat in the upper radiator hose or making a radiator hose with a u shaped bend that would keep the coolant from simply rising/circulating into the upper radiator tank.

If I installed the second thermostat, I would trim it down so that it would sit inside the radiator hose right up against the cylinder head outlet tube, then I would put an extra hose clamp around the hose only to "lock" it in place.

I wish I could speak with a Honda engineer to listen to the reasoning as to why they designed the motor with a lower hose thermostat- surely there was a good reason.

Anyone tried this? Good idea? Bad idea?

Does anyone with a lower thermostat setup see their temp needle go right up to operating temp on a 40 degree day after driving only 5 minutes with the heater off?

Should I remove the lower thermostat while I am testing the upper one?