If you can use a lathe, the only tricky part is figuring out the distance that the lower insert sits below the seat of the thermostat (note: thermostat from 95-99 Hyundai Accent 1.5L).
If you use the dimensions of Kap's lower insert, you will need to machine the stat base to give a distance of 1.525 inch
minus the thickness of your crushed gasket. Shown in the diagram is not correct.
Curtain area of bypass valveShould be equal to the area of the bypass port (lower hose fitting).
-bypass port diameter (hose fitting) = .479 inch
-pi x (.479/2)^2 = .18 inch^2
-bypass insert inside diameter = .87 inch
-curtain area is = pi x diam x lift
-curtain area should be = pi x .87 x lift = .18
-thus lift (bypass valve gap) should be =
.066 inch when the top valve is just cracked (190°F)
SoThe gap at the bottom bypass valve is
.07 inch just cracked past the end of the sleeve (the point where coolant really starts to flow to the radiator). Perfect height! But the thermostat sits on a gasket.
Again: machine the stat base to give a distance of 1.525 inch
minus the thickness of your crushed gasket.