The photo doesn't seem to be working.

--Ian

Your past few image links are bad and you should feel bad /zoidberg/.

Also I can't tell how far off center it's drilled (see above comment) but we could chuck it up in the mill and make the hole/thread centered?

Its because I hosted them on MT rather than imgur like I usually do. :facepalm:

Did the valve cover image work? Trying to figure out how far to go back.

Possibruu but it should be OK with the 10.5mm drill. I can bring it by and we can give it a shot. :D

I only see two broken image links (the most recent two).

Rehosted on imgur. Better?

Absolutely.

Yeah, photos work now.

You could also drill to 7/16 and thread it for 1/4 NPT, adapters from that to -6 are common.

--Ian

I thought about that, but I have a pretty vicious hate for NPT and I don't own a 1/4"NPT tap. Either way I'm buying a drill and a tap so I figured I'd go for metric and expand my meager collection. The fittings are going to come from Summit either way so :dunno: I'm also trying to stick to just a couple brands of fittings. So far its all Bat-Inc and Fragola, and maybe 1 fitting from Russell.

In other news, the great big bastard coolant fitting on the back of the head, the one that feeds water to the oil preheater/cooler I'm eliminating, is way larger than 3/8" NPT. I don't want to create a "cursed water plug" esque situation back there but I do want to block it off. Anyone have a clever idea?

I'd prefer to avoid things like Curly's "bolt and hose clamp" plug :giggle:

The metric threads are straight/parallel, right? If so you're going to need some external way of sealing them -- a rubber washer?

--Ian

Yes sir, requires a seal in the form of an aluminum crush washer

https://www.miataturbo.net/attachmen...ine=1430154021
http://www.summitracing.com/parts/fra-491953-bl

I got a set screw that was just a bit bigger than the outlet ID, ran a tap into the outlet and JB welded the set screw in. Has held up to a year of tracking with no issues.

I cut it off flush to the head, tapped it with a 3/8 NPT and plugged it with a brass plug. The ID of the fitting is almost perfect for the 3/8 NPT tap. My engine hasn't been run that much (still finishing the car) but so far no leaks.

Interesting... you literally just tapped it into the remnants of the steel fitting?

Yep - I did that, exactly.

Humm... are there pics somewhere I'm not seeing? That bastard must be pretty thick.

Hard to see in ths fuzzy pic, but it's right behind the black -AN fitting sticking out from the reroute spacer (behind the water outlet). IIRC, the outlet is pretty thick.

https://www.miataturbo.net/attachmen...ine=1430319144

Daymn, no kidding. That steel is much thicker than I thought it would be. I browsed through your build thread and didn't it so I do appreciate the pic :bigtu:

I'm still on the fence though. I know removing the whole thing and tapping the aluminum would be "better" in the long run, but I'm lazy and I already have the 3/8NPT tap https://www.miataturbo.net/attachmen...ine=1430171541


On a completely semi unrelated tangent, I drove the Miata to work this morning for the first time in probably 2 months. Lolz were had and I got revved on by an SRT4 at a light. I hope beating a stock Miata off the line makes him feel better about his day job :rofl:

Glad the pic helped (I probably didn't post it 'cause it was such a lousy picture).

I thought about trying to remove the whole thing, but it wouldn't budge when I tried with a channel-lock. So I just cut the b**ch off and tapped it.

Nothing wrong with putting pipe threads into steel. In fact, most pipes used in industry are steel and pipe threads were specifically designed for that material.