I posted a picture a ways back. It's barely wet. And just on one cylinder.

im quite sure it was honed right. The other 3 motors that were sent in with mine aren't smoking.

Ya never know. Friday afternoon, and the guy is thinking about the weekend. Monday morning, and he's tired from staying up late Sunday night. Shit happens.

Why would it only be on one cylinder?

The "wet spot"

https://cimg6.ibsrv.net/gimg/www.mia...95d4f0efd9.png

Hey, I'm trying to help. You can't rule out everything and still have a problem.

I'm not discounting your suggestion. Just countering it with the reasons I've been using to rule it out.

There is one last hope.

https://www.miataturbo.net/general-m...tion-gas-8955/

I'm running really rich at higher rpms. Haven't had time to really tune it in. And rich = safer than lean.

Not sure what I'll do if it keeps smoking. Probably valve stem seals again or something. Just keep replacing them until i run out of money.

New ground shim back in. Clearance is right where I wanted it to be. Machine shop killed it. They even showed me how the surface grinder worked.

Hopefully will have it driving tomorrow. I think I'll have some dry time to spin some tires.

https://cimg0.ibsrv.net/gimg/www.mia...40d9b7ce9b.png

Surface grinder is win.

Gotta ask, do you screw with RTV on the half-circle spots when you put the valve cover gasket on? It takes me forever to extract it all to re-seal the thing if I have to check the valve clearances..

Yeah. I just scrape it off with a blade and reapply.

Wow you've come a long way. Sorry if you mentioned this- Just skimmed to catch up. (Don't holler and throw shit for stupid question, but) Are the rings directional and could one on number 4 be upside down?

Rings are directional. But remember this only happens after driving hard (really hard) then idling. Normal driving is fine.

How dirty is the inside of the intake manifold? If it's not the turbo or valve stem seals then. just flinging ideas to help ya' think:
-rings on 4 didn't seat as well as the others
-there's enough residue left in the intake manifold to make it to 4 and smoke
-something keeps messing up a valve seal
-you've got a weird, almost unheard of crack in the head

Leakdown is ~3% on all cylinders.
intake manifold was super dirty. That like my last hope. I cleaned it out real good.

AIUI, the state of the oil control rings doesn't really show up in leakdown tests.

--Ian

This is true. My thought was that if something had caused #4 to break in incorrectly it would also show in the compression rings.

if the gap is big enough for oil to get by I would think it would show up in a leak down test right?

Compression rings != Oil control rings.

If the oil was able to get into the combustion chamber then it was able to get past the compression rings.

Not for the oil rings at least. If they fail, it coats the comp rings in oil all the time and you show good compression, like driving around doing a wet compression test all the time. The motor I built years back where I literally reused the old rings, it had 140 or so compression, but burned a quart every 200 miles or something crazy like that.