Engine apart for big maintenance. FM2 Turbo. Coolant line questions, please help
 

Hello Everyone. First and foremost, to those who post useful information for me to resolve my issues, thank you in advance.

Background.

1992 1.6 miata
Full fm2 turbo kit
M-tuned coolant reroute

I bought this car 2 years ago, and I am just getting around to do doing some big maintenance before I start tracking and cruising in the car. I am fixing a bunch of coolant leaks, and changing the timing belt and water pump since its last change was undocumented. Also doing copper plugs and wires.

So my questions.

I have that ugly stump on the front of the motor where the thermostat use to be. I would like to remove it, however there is a sensor on top of it (one wire), and two coolant lines. One goes to the turbo, and the other to the intake manifold. So my questions are really, how do I go about deleting this thing? Can I delete the intake manifold cooling lines? I do not drive the car in the winter. Where do I plumb the coolant line for the turbo. One line goes to where the coolant goes to the heaer core. I guess I should be able to plumb the second to the back of the m-tuned fitting on the back? Is there any issues with this? What about that sensor?

Easiest way would be to leave the stump there, but it is pretty ugly. I would like it gone.

Thank you!

Someone with more 1.6 knowledge but if you're on a stand alone the fans should be getting turned on by the stand alone, so you dont need the switch. And IRRC for the 1.6 the manifold coolant is for the warm up airflow thingy which shouldnt be a big deal on a stand alone car only driven in the summer so the water doesnt need to flow there. It should only need to flow from the back of the head on the engine side of the thermostat to the turbo.

I've got a bunch of pictures in my build thread for my reroute. I deleted all of those little lines for reliability. I have a Greddy though, so I didn't need to worry about water cooling the turbo. I haven't experienced any issues with cold drivability with all that stuff gone (including the Air Valve).

To have water flow to your turbo, you need to pick up water that is pressurized relative to the water pump inlet (i.e., from engine side of thermostat). Plumbing from the intake manifold port is convenient and avoids the hot-side parts. Basically a single line running across the front of the engine. You should be able to route it so it's not hideous.

Andrew Savington (Trackspeed) sells a block-off kit for cheap. Or you can build your own.

You can do away with the intake manifold lines completely. Just run lines:
Back of head ->oil cooler plate->mixing manifold
It's pretty obvious once you have the intake manifold completely off, but I have a pic somewhere.

First part of removing the front water neck is getting a 30mm freeze plug. If you're feeling super thrifty, I can send you one in the mail. Just got done doing this same project, accidentally bought a 10-pack of freeze plugs, so I've got a shit ton of them laying around.

He has a 1.6. I believe their intake manifold coolant lines do more than our 1.8s. On the 1.8s its just throttle body heat, on the 1.6 I believe it has something to do with cold start idle up and melting wax. And he also doesnt have an oil cooler.

1.6L = loose butthole. Funny side note, pretty sure Leafy was the one who talked me through the intake manifold bypass on my 1.8L

I do have an oil cooler. Its one of those plates that comes off the oil filter.

1.6 is fine for me. I bought the car this way. Its plenty fun the way it is. Really I want a V8, but that will come with time.

IMO, the cleanest way to run the coolant lines on a 1.6 is the following:

Water return:

Remove your mixing manifold from the water pump, remove OEM nipple with pliers, drill and tap for fitting (I used a 90deg -6an earls), reattach to water pump. Do yourself a favor and replace the heater tube o-ring while your at it. You can see the mixing manifold drilled/tapped on my engine in the below pic.

https://www.miataturbo.net/attachmen...ine=1371172605

Water feed:

1.6 engines have a water port on the exhaust side of the block right next to the oil port. I believe it's threaded for m12x1.5 but I cannot confirm at the moment. See below picture - it's the larger of the two ports at the back of the block, i.e., the one NOT circle in red.

https://www.miataturbo.net/attachmen...ine=1371172605

Going this route allows you to remove the unused water neck while keeping your coolant lines very short ... which is good since PTFE lines aren't cheap (do not cheap out and use rubber lines). Do it once, do it right.

-Zach

^ This is what I just did on my vvt build, that and route all the long ss lines along the rear of the engine for cleanliness (97 block).

It's a 30mm freeze plug on 1.8 cars (probably same for 1.6) if you want to do it, about $3 from Mazda.

That water location is on the 1.8 blocks to? Mines not here.

For 1.8 engines, those ports are only found on 94-95 or 04-05 MSM blocks.