curly

iTrader: (25)

Removing it has been covered in length. 33mm freeze plug I think (could be wrong, search), and it's held in by two bolts, sealed with an o-ring.

olderguy

iTrader: (19)

No, it is not a horrible idea. But, with the speed at which the water travels, mixes and combines(as long as your system is in good shape), most of the water in your system is already warm and the little bit of extra heat is quickly dispersed into the massive amount of cooler water from the radiator entering with it at the pump inlet.

phillyb

iTrader: (8)

i was told 30mm by planet miata

phillyb

iTrader: (8)

also, do you have to use the freeze plug?
can't you just use a gasket and the block off plate?

olderguy

iTrader: (19)

You could, but the block off plate will need to be thick enough so that it will not flex and will need to be perfectly flat on the head without the gasket added.

phillyb

iTrader: (8)

it's the block off plate from begi...i'll go talk to the builder later.
i need some sort of plug for my oil pump as well anyway

fastivab6tg25mr

why not just get the freeze plug for a protege... then you dont need the plate

phillyb

iTrader: (8)

have a pn?
i need to order something else from mazda as well...might as well get them both

curly

iTrader: (25)

The freeze plug is thirty cents from o'rileys.

freedomgli

I'm planning on installing the M-tuned coolant reroute and deleting the front water neck by fitting a freeze plug and block off plate in its place. I'm also deleting the coolant hoses that go from the oil filter to the stock throttle body and from the stock throttle to the front water neck because I'm running ITBs that have no coolant provisions.

Instead of trying to splice a bunch of Mazda hoses together to accomplish this, I would prefer to get a custom length of rubber coolant hose so that it is continuous from the oil filter cooler outlet to the mixing manifold inlet. Can anybody verify what size hose (I.D.) I should use? Is it 8mm all the way?

Leafy

iTrader: (1)

I believe I used 5/16 hose the whole way.

freedomgli

Thanks Leafy. I guess the trick is to route it in such a way that it doesn't contact the alternator, water pump, A/C or timing belt(s) and pulley(s).

freedomgli

And if I wanted to delete the small diameter coolant hoses that run from the back of the head to the oil/water heat exchanger sandwich plate and to the water pump inlet/ mixing manifold, is that OK? Or are those small lines necessary to promote faster warmup with the M-tuned coolant reroute thermostat location? Just trying to eliminate potential failure points and need to decide whether I should plug those holes now with the engine out or just run the small coolant hoses and hope they don't fail on me.

hornetball

iTrader: (4)

You can delete them. I always do. Pics in my build threads.

The M-tuned thermostat should have a small bleed hole in it that ensures it is seeing fresh coolant temperature (i.e., no stagnant/cold coolant). During initial warmup, most coolant takes the path through the heater core and into the mixing manifold on the exhaust side of the engine.

freedomgli

Thanks man. So JB Weld and 1.6 rubber cap for the fitting on the back of the head and pipe fitting on the mixing manifold. Do you recall offhand if that was 1/8 NPT? Looks too small to be 1/4 NPT but what do I know.

Also, did you remove the stock oil/water cooler or did you leave it and simply add another sandwich adapter for your air/oil cooler?

codrus

The standard sandwich adapters (Mocal makes it, I think?) don't fit without the stock oil/water cooler, because the outlet fittings want to be in the same space as some of the ridges on the block. It's light, just use it as a spacer.

--Ian

Landrew

iTrader: (2)

Trackspeed has a nice clean kit for $20

Trackspeed Engineering

hornetball

iTrader: (4)

I JB Welded a hex set screw into the water fitting on the back of the head and then capped. The mixing manifold plug was indeed 1/8NPT.

I removed the stock oil/water cooler, but you can leave it in place as a spacer like a previous poster mentioned. If you do remove it, then you'll either need to source another spacer (you could use a sensor port sandwich adapter as a spacer) or get the shorter threaded tube from the 1.6 and then figure out how to avoid the block webbing. The cheap thermostatic adapters with the bimetal coils instead of wax-plug pistons actually work pretty well for this because they are a much thicker. Thermostatic adapters with fittings that face outward at a 45 degree angle (Greddy) also help avoid the webs.

Most retain the oil/water cooler and use the well-proven Mocal thermostatic adapter. You can't go wrong with that. I cheaped out with a Haynes and haven't had any problems. YMMV. Look for "thermostatic sandwich adapter" on Amazon and there will be a lot of options. Miata oil filter thread is 20mm.

freedomgli

Here's what I did.


Front thermostat housing removed, Dorman freeze plug installed, Trackspeed Engineering front coolant block off plate installed with stock bolts shortened and blue (medium strength) Loctite.


Water outlet for small oil cooler lines plugged with 1/4-20 set screw and JB Weld. This was a bit tricky as I didn't let the JB Weld set up enough before inserting the set screw, which meant any JB Weld that I packed in afterwards wanted to run out the hole. So when the first batch set up I rotated the engine on the stand 90° so the fitting was pointing straight up, I mixed up another batch and filled the rest of the hole. Covered with rubber plug (Mazda p/n FEA7-13-104) for belts and suspenders approach.


Stock oil cooler lines deleted. Capped holes with rubber plugs (p/n FEA7-13-104) to keep foreign debris out of the stock oil cooler in case I ever want to go back. Overkill but very tidy.


Removed elbow in mixing manifold with vise grip pliers. Drilled and tapped for 1/8NPT plug. I used the same Earl's aluminum plug as my fuel pressure gauge adapter. Coated plug with Permatex Aviation Form a Gasket No. 3 since that is what Jamestown Distributors recommends for all NPT fittings.

How to Properly seal Fuel Fittings and Fuel Lines

hornetball

iTrader: (4)

Nice and clean. Cool intake manifold.