Miata Turbo Forum - Boost cars, acquire cats. - Excessive oil burning, oil jets, stuck rings, acetone

- Engine Performance (https://www.miataturbo.net/engine-performance-56/)

- - Excessive oil burning, oil jets, stuck rings, acetone (https://www.miataturbo.net/engine-performance-56/excessive-oil-burning-oil-jets-stuck-rings-acetone-90480/)

Quote:

Originally Posted by Micztor (Post 1370869)

So when removing the oil jets, do you just let them be have the bolt hole open, or do are you supposed to screw a bolt in. Sorry for the silly question, I'm just trying to do it right. Thanks

You have to plug the holes with 10x1.25 10 mm plugs.
Otherwise you'll have a very short lived engine - no oil pressure, fried bearings, mayhem...

Quick update:

Engine is out and disassembled, AND things look a bit grim at the moment.

Bearings are bad. #4 rod bearing has flaked.
The engine had a bad miss on #4 for a little while due to a collapsed valve seat.
Everything in the head has been replaced since, but the damage is done I guess.

#1 cylinder wall is scored.
Pistons have scratched skirts.
Crank needs polishing.

And yes, oil control rings were pretty much gummed.

Please stand by for massive photo dump...

Pistons:

(I cleaned one, then remembered I should have taken a photo.. Skirt scuffing can be seen, too)

https://cimg9.ibsrv.net/gimg/www.mia...a1f63a9dfd.jpg

The block is getting custom sleeves.

There's no getting around those scratches.
I am not buying bigger pistons. I have 84 mm pistons already.

Aaand, this is how you take your engine to the machine shop all the way across town, the right way...

https://cimg6.ibsrv.net/gimg/www.mia...0d683eb3ab.jpg

https://cimg8.ibsrv.net/gimg/www.mia...dc206e192c.jpg

500 ccs of smooth power...

Wow, the bearings...

Did you have an oil pressure problem? Or starvation? Looks like debris in the oil as well.
What oil were you using?

I was using Mobil Super 3000 5w40

https://cimg9.ibsrv.net/gimg/www.mia...9c5a6f2a56.jpg
I'm thinking about using Shell Helix HX8 from now on.
And no, we do not have Rotella T6 over here.

Also, I have a "shimmed" oil pump, and great pressure.

Oil change intervals are no more than 3-4K miles.

Yikes, why do you think this happened?

Quote:

Originally Posted by ridethecliche (Post 1376628)

Yikes, why do you think this happened?

Flaked bearing is self explanatory. (See related post)

The rest... I can't say.
Bad oil filter? I'm using a local brand.

Quote:

Originally Posted by Godless Commie (Post 1376631)

Flaked bearing is self explanatory. (See related post)

The rest... I can't say.
Bad oil filter? I'm using a local brand.

Yeah, I saw how pitted and unhappy the bearings looked.

I guess this is a good reminder that I should swap out my oil and fuel filter over the winter...

I've heard....but not seen first hand that a flaked and pitted bearing like that is the result of detonation hammering them. The other bearings are more indicative of trash flowing through the engine (most likely from the flaked bearing) I would very closely inspect the #4 piston for signs of detonation. The collapsed valve seat is another indicator of that cylinder being hot from detonation. I see that you're running a coolant reroute, normally not running one is why you only see this issues like this on #4, the back cylinder runs hotter due to lack of flow and is the first to detonate when running on the ragged edge. In your case maybe it's a lower flowing injector or just dumb luck that it's #4 this showed up on.

You want to find out how much it would be to import one? I have two block sitting here and you can have one for the shipping and import duty, land freight could not be that much...