Failing: Pulley or Internals?
 

**1.6L long nose motor**

Judging by this video, does this look / sound like a crank pulley issue or spun bearing? I've seen some play on other people's pulleys but it doesn't look as bad as some of the youtube videos I've seen. Just fielding some opinions before I drain the oil tomorrow. Noise has gradually gotten worse over a few days of driving to this point where the video was taken.

Your pulley looks like it is wobbling a bit. A knocking rod sounds more internalized than that. It is hard to tell with out hearing it in real life though. I guess it could be. I think I have another pulley I could mail you if I could find it.

Doesn't sound too much like rod knock, it's emitting a squealing sound.

man I thought mine was bad, that is just impressive. Try another pulley and see.

Pull the belt off and check the pulley. Maybe you just pulled a leatherface and the pulley isn't on tight.

Agreed, judging solely by the video, this looks like a pulley issue. You might need to pull the timing belt off to inspect the nose of the crank, but start by just pulling the accessory belts and determining whether the pulley itself just isn't bolted down correctly.

I'll give it a shot. The motor has been running for a little over a year as is, so if anything its worn or coming loose. Should I expect any bearing damage due to play?

I'm certainly no expert on the matter, but if it's just the accessory pulley I would expect the bearings to be fine (and even if there is doubt, as cheap as a new motor is, you're best option is probably to just assume they are fine rather than pulling the thing apart).

Ouch. I'd say pulley. You probably do have bearing damage but from what I've seen, a lot of motors work "just fine" and then they get pulled apart and the bearings look like shit. Which means you're probably ok.

If you want to know the status of your bearings without ripping motor apart, drain oil, look for shiny specs, and send oil to blackstone labs for analysis hustler style. $30.

I'm going to go out on a limb and say "perhaps not."

When a shortnose engine suffers The Failure, the damage usually seems to be localized to the crank nose, the key, and the timing belt pulley. It's all just guessing at this point, but if the problem does turn out to be nothing more than a loose pulley, I'd think your best bet is to just fix it and move on. In a worst-case scenario (if there is already damage to the crankshaft beatings), it's not like you're going to make it any more broken by trying the simple fix.

Joe but most people don't pull apart the motor when pulley has The Failure. Regardless of damage, yes, the bearing damage (if any) is not terminal.

Update:

Crank pulley bolt came loose with almost no torque. Everything was worn. Replaced a lot of the parts, torqued it up with copious amounts of red threadlocker and shes running fine. No metal in the oil.

https://www.miataturbo.net/attachmen...ine=1313382452

There was coolant hanging out in that area, water pump must be leaking. The pulley still wobbles every so slightly, but I'll be building a block over the winter so I'm not too worried about it.