It says misguided in the thread title... but there has been practically no issue! You're either lucky or not as misguided as you thought :bigtu:
I can only hope when I build a motor it goes as well.
That gearbox is so clean its unnatural.

I'm having issues. No autox for me today.

So, the clutch started feeling funny. It's bogging down the motor when I press it in (down to 4-500rpm, sometimes killing the motor), making a little bit of noise, and showing inconsistent pedal feel. When it doesn't die, the ECU will kick in and fix the idle after a second or two. The bogging happens both when in neutral and when in gear... any time I press the clutch. Sometimes the pedal feels alright, sometimes it feels floppy for the first several inches of the stroke. This has been accompanied by oil pressure reading about 10psi lower than it was. At a hot cruise before I was at 60psi, now I'm at 50. At a hot idle, I was around 20psi, now I'm around 10. And I think it's unrelated, but I'm dripping coolant intermittently. Temps are running around where they should, with oil sitting at about 215F on the highway and water right at 180.

Any parts on my car that I havent replaced are OEM 99 parts with 75k on them. I ran 10w-30 Rotella conventional for the first two oil changes, and the last time I changed I went to 5w-30 Prestone conventional. I'm using the larger M-110 Mobile 1 filter. The car has around 500 miles on it since the rebuild.

The oil pressure thing is throwing me off. Or at least making me worried. Not so much the pressure itself, as it seems I'm still in the realm of "normal", but the fact that it changed by ~10psi across the board, and was accompanied by the changes in the clutch.

My attack plan is a bit of a "spray and pray" method, I'm going to try a few different things and hope I can narrow it down:

- As far as the clutch goes, it seems the standard internet answer for a clutch-related idle droop is to check the transmission switches that are triggered when you press the clutch. Easy enough, I'm going to take a look at them. If that fixes it, I'll be a very happy individual.

- Re-bleed my clutch and check the pedal adjustment

- I messed with the idle screw when I pulled the intake manifold apart. The ECU is doing a fine job of correcting it, but I'm going to jumper the appropriate pins and adjust it manually.

- Drain and check my oil... It's been changed twice at this point, and both times the oil that came out had a slight metallic sheen to it, very visible when I sloshed it around. It was my understanding that this should clear up after a couple oil changes... I'm hoping it comes out looking fresh, because I might have some serious issues if its not clearing up.

- Get someone to press the clutch while I watch the crank pulley for movement. I don't expect this to be the issue, but I saw this thread on GRM last night where Keith got me panicking about thrust failures: https://grassrootsmotorsports.com/fo...nt/5865/page1/

- Check vacuum fittings/hoses


Any ideas?

You jinxed me! :facepalm:

Something else I didn't think to mention was that the EGR vacuum solenoid was missing and the vac lines were plugged. It was replaced yesterday before around 100 miles of driving. The car is showing a CEL, and I assumed that was why, but it didn't go away after yesterday's driving. Running to the store to buy an OBD reader to see if it's still the expected code or if something else was triggered.

P0325 - knock sensor malfunction. The knock sensor wasn't plugged in. That couldn't seriously be causing all of this could it?

Got the knock sensor plugged back in. But I also noticed something bad... Somewhat significant movement in the crank pulley when the clutch is pressed in. Fuck.

https://www.miataturbo.net/attachmen...ine=1464545405

https://www.miataturbo.net/attachmen...ine=1464545405

Motor goes in, motor comes back out. Is it likely that rods and pistons suffered? Or do you think the damage was limited to the block and crank?

I fucking hope the head is okay. I just want to be at autox right now :(

That really fucking sucks. Sorry to see that.

Aaaannnnddd... the head didn't escape it. Time for a new long block I guess.
https://www.miataturbo.net/attachmen...ine=1464555374

Damn, man. Best wishes. Any idea what caused it? Oil starvation?

I'm thinking it was a thrust washer failure before the rebuild that I didn't catch. Exacerbated by the clutch and pressure plate I put on it. It took it a week to self destruct I guess.

I just did a timing belt job that had a thrust washer failure. Sorry to see that man.

Well you beat my record of a 1000 mile stint on failed bearings

:party:

Alright. Motor build round 2. NB2 motor and NB1 head ordered. Pistons, rods, oil pump, gaskets.

This car is going to run one day.

Anyone have a recommendation on a machinist in Colorado who has done more than a couple BP motors?

My crank walk: https://www.youtube.com/watch?v=slTD...ature=youtu.be

That makes me uncomfortable just looking at it. Sad day.

Nooooooooooooooo

I'm not sure I'm following what happened, these were reused thrust bearings? or fresh out of the box & failed?

New thrust bearings. I think my motor had a pre-existing case of crank walk that I didn't recognize (which could explain why it failed in the first place). Then I assembled the motor with new thrust bearings and everything seemed fine. Combined with a heavier pressure plate it rapidly machined itself.

That's my best theory.

Expensive damn lesson.