Joe, put down the scotch. He's saying run that line to the heater core, and just use the normal fwd thermo cover with no spacer with a thermo in the rear. I guess you could always used one of these in the upper rad hose for the temp sensor.

Yes, I understand.

My point was that while this is close-ish to the original FWD configuration, it is not the same. In the 323, the feed to the heater core was taken from the back of the head, out of a port right next to the thermostat. In other words, there was constant circulation of water around the thermostat because it had to go up that way to get to the heater core outlet.

In the design as shown, water exiting to feed the heater core is not circulating past the thermostat.

It won't be nearly as bad as a remotely-mounted thermostat (since the thermostat is at least inside the head) but it's not the same as the OEM configuration.

im kind of lost on what your saying, forgive me:

the 323 GTX intake manifold flows coolant from the exact same space as that miata intake manifold is drilled/tapped, circulates it coolant through the oil cooler and goes into one bung of the heater core doesn't it???

https://www.miataturbo.net/attachmen...ine=1363803052
https://www.miataturbo.net/attachmen...ine=1363803052

sorry for crappy quality.

lol i was waiting to get roasted from you guys, i should of explained myself more clearly.

There is a bunch of possibilities for the green temp plug.

The reason id do it this way is:
-People who cant weld aluminum

-People who don't want to remove their head to drill/tap the actual head rather than the intake manifold, (Intake manifold is easier to come out IMHO)

-People who are doing a budget build.

or lastly
-People who have 2 miatas, and 1 festiva with the same problem, and dont want to spend 300$ on spacers alone. (aka me)

I hope you meant $30.

????

i was referring to the begi spacer, but $30 sounds better.

Interesting.

Historically, I have always referred to the following diagram as a reference for the FWD configuration, which comes from the '89-94 323GTX with the 1.8l BPT engine.

https://www.miataturbo.net/attachmen...1&d=1363823635

Clearly, the coolant supply to the oil cooler / heater core and throttle body is being drawn from a port at the back of the head, directly adjacent to the thermostat housing.



I did a bit more googling, and came up with a diagram which differs slightly:

https://www.miataturbo.net/attachmen...1&d=1363823635

The source for this image designates it as referring to the '85-88 model with the B6T engine. This diagram matches your description, with coolant being sourced from a port in the intake manifold.

So it would seem that Mazda modified the configuration between the two engines in the 323, much as they did with the transition from the B6 to the BP in the Miata.

This is the best way imo,

https://www.miataturbo.net/attachmen...ine=1363826347

if you want a heater drill and tap as has been said.

Dann

Is that your coolant sensor (or, rather, sensors) installed in the line downstream of the thermostat?

lol...i believe it is.