Carnage -- But not what I expected
 

I used Joe's method and got the head off without any drama. Cylinder #4 was steam cleaned. All the others were nominal. I was astounded at the condition of the cylinders. No scoring, still had nice cross-hatching. At 200K no less. No signs of det that I could see (thanks, MS).

Here are the pix, pretty boring except you can see what a great crud-cleaner steam was on #4:

Cylinders and Piston Tops:
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860

Carnage was on the exhaust system. Turbo to downpipe was fine, but as soon as I unbolted the downpipe, it bacame obvious that my turbo was loose. It turns out that one of the bolts had sheared, and the other three had a bad case of thermal creep. I sheared them during "removal." Lucky for me, the safety wiring and well-supported downpipe kept everything together and fairly leak free. Inconel studs, here I come . . .:
https://www.miataturbo.net/attachmen...ine=1349662860

The only other heat-related issue was the turbo oil drain hose. It was cooked. Cracked while trying to remove it. Hard as a diamond.
https://www.miataturbo.net/attachmen...ine=1349662860

So, some long-term turbo lessons learned. The above is 15K miles and about 1.5 years of turbo'd DD.

No Fix
 

Finally got the car back together. Went for a drive and no change. Car seems to drive fine for the most part. Pulled into a gas station and it started missing at idle. On restart, big cloud of steam. Got it back home and, sure enough, coolant is low. It's going somewhere.

Head was checked out and rebuilt. No issue there. New headgasket, water pump and TB (I was overdue for some maintenance).

Could I have a cracked block? I didn't even think to check that when I had the head off. I've never heard of a cracked block unless someone is making insane power on an overbore. My power level is pretty tame, but the block is well-seasoned (pushing 200K).

I'm bummed.

Sorry to hear about this Rick, I was looking forward to hearing good things about the car this weekend.

Seems coolant is getting into the exhaust some how. Possibilities would be cracked head, block or head gasket. You have 2 crossed off your list but I wouldn't come to conclusions just yet. How does your oil look? Any signs of milky oil or is the exhaust the only place you have noticed so far?

I would start with a leak down test to see if it is getting into the combustion chamber. The smallest cracks can be so very hard to find. They can cause over heating or coolant loss.

If you need any help I am just around the corner, let me know!


PS: Where did you get your head gasket and what brand was it? My coolant loss problem I had a few months ago lead to a junk head gasket, your new gasket could be your problem I have seen many come damaged or not properly sealing right out of the package.

Oil is perfect. It was fine first time as well.

Gasket is Mazda OEM.

Drove with the new suspension. It was nice. Very comfortable, especially considering 500/375 spring rates. Sitting a lot lower.

Is it now dragging up and down your driveway like mine does? :vash:

My first check would be a leak down test just for the hell of it. Next stop would be Auto Value for a Fel-Pro MLS gasket. My OEM gasket I had gotten from Mazdaspeed Motorsports turned out crap right from the get go. Not saying yours is it just seemed to be the fix for mine. Completely look it over for any cracks on the cylinder walls and water jackets.

We even had the same results on #4 cylinder.

https://www.miataturbo.net/attachmen...ine=1339987234

Did a compression test.

#1 166
#2 162
#3 165
#4 212 ?!?!?

Tip of compression tester came out of #4 dripping coolant. I'm guessng the water in #4 is raising the compression ratio. Still don't know where that water is coming from.

Next step is the same no matter what. Pull the head (again).

For original rings those are great numbers. But you're correct on the raised compression, most people add a little oil to increase their numbers when testing.

Seems like a lot of trouble but if you pull the head and don't see anything I would try to throw another head gasket on there and try it out. Knowing the head is good a new Fel-Pro (or whatever these other gays may suggest) may fix it, if not your problem lies in your block.

Get rid of those cardboard gaskets, OEM is over-rated. You need the metal 4-ply ones.

How could it be a cracked head? You mentioned it was checked by the machine shop fully rebuilt. Would take it back to them, whoever it is.

I had a similar problem on my car, went crazy checking left and right, and turned out to be a bad block, which by the way I am working on it right now.

http://www.enjukuracing.com/products...m,-.040in.html

https://www.miataturbo.net/attachmen...ine=1355160068

I bought ARP head studs, shaved cylinder head, double metal head gasket, etc, and nothing fixed the problem. It seems that block is junk...

If looking for engine blocks, Mercury Capri (also the cyinder head) are the same if when you go to a junk yard and all the Miata ones are gone.

Yeah, I'm pretty sure I'm down to the block. The compression test really doesn't point to a head gasket. On my original tear down, the head gasket didn't look bad. It was still well-adhered and there wasn't an obvious path from any water passage to the cylinder (see pix above). I've seen pictures of bad head gaskets and mine just didn't look like those.

I've got other issues with the short block anyway. I've been living on a Locktite fix to the small-nose crankshaft for 50K miles. Probably overdue to fix it right.

So, that's one other that has had a block crack. Maybe it's not as rare as I think. I also don't have a coolant reroute. Contributor?

Stock HG is MLS.

Only on 1.8's, the 1.6 cars got the graphite or whatever it is.