Seriously, I'm at a loss as to what that might be. It DOES look like a plastic cage for a set of ball bearings but there are not ball bearings in a BP. There are however ball bearings inside an EFR... :noes:

Plastic or metal, ferrous or not (stick a magnet to it) will also help with identification. I mean, if its plastic that's not going to help, but you get the idea. in4answers.

<p></p><p>Um, is that a chunk of crank missing?</p>

Looks like a grind mark from balancing.

Those pieces have been bugging the crap out of me. I've been scouring exploded diagrams and parts lists, and I just don't see where it's a part of anything that should be inside an engine. The best I can come up with is something that got injested.

Ingested into the oil pan?
<br />
<br />Maybe you just blew another head gasket and over reacted?

Pics of the head? How do the valves look?

--Ian

I've got a dollar on the bottom end not being the cause. But thank god you pulled it because those bearings look like they got a hard dry ---- beating.

I didn't think it made any sense...

Well as Aidan stated, it may have been premature doing a tear down of the block, but those bearings made it rather fortuitous that I did.

EO2K, the black pieces are not magnetic, but haven't tested if they are plastic or not yet. Turbo spins perfect without any catches/play.

Just looking at the bottom of the valves nothing is amiss, they literally only have about 500 miles on them so they still look new.

My guess is a blow head gasket and maybe coolant making it into #4? Upon closer inspection the surface film of oil is looking rather milky on the head/oil pan. But I shut it down hot, and it sat outside in the rain for a couple days.

Some rust on the cam lobe tips, but the head looks normal besides that.

https://www.miataturbo.net/attachmen...ine=1442179306

https://www.miataturbo.net/attachmen...ine=1442179306

Not sure is this is a kosher thing to do, but could you pour a bit of oil into all the cylinders and see if 4 drains faster. Because if you don't have to pull the pistons then you don't have to hone the block, etc.

Pistons are out of the block.

Should the oil pump be rebuilt while it is out of the block? It is a B.E. billet pump. Didn't have any real issues with oil pressure but wasn't sure what the S.O.P. was on it.

Jafromobile is my spirit animal.

While I'm trying to figure out my next move, which I believe to be the following:

-84mm Wiseco XX rings
-MLS Headgasket
-Water pump &pulley kit and associated gaskets
-Crankshaft front seal set
-Oil Pan Gasket Set
-Rear Main Seal Set
-ARP Flywheel bolts(need new ones anyways)
-Camshaft front Seal Set
-Exhaust & Intake Manifold Gaskets

Not sure if I'm forgetting anything there, but it roughly works out to be $330 to rebuild the bottom end in parts, no clue what associated labor will be depending on who I get to rebuild. I want to take it up to Curly in OR, but not sure if I have the time to take that trip.

Going to resurface my flywheel as it looks like it is in great shape. Probably get a new 6 puck ACT clutch disc as mine is getting a little worn out. Reuse my pressure plate as it still looks good.

https://www.miataturbo.net/attachmen...ine=1442196749

I know the person who rebuilds it will hot tank and clean all these parts but I figure less time cleaning = less labor costs to me.

Cleaned out my oil pick up

https://www.miataturbo.net/attachmen...ine=1442196749

Removed gasket from oil pan and cleaned all the things

https://www.miataturbo.net/attachmen...ine=1442196749

Ditto on the crank case cover(not sure on the right name)

https://www.miataturbo.net/attachmen...ine=1442196749

Ditto on the block and chased all the threads to remove gummed up gasket.

https://www.miataturbo.net/attachmen...ine=1442196749

All looks very good.

You can reuse your flywheel bolts unless theyre damaged. Also you're looking for felpro's "lower conversion" gasket set. It'll have everything for the short block, minus rings, bearings, and a few seals on the sides of the block.

Thanks for the heads up.

In regards to the main and rod bearings, is standard the norm that everyone gets or is that something you buy after measurements are taken into account for clearances/tolerances.

Also saw Andrew and Emilio state its hard to find ACL bearings at the moment. What is a recommended alternative?

I have a set you can buy. Youll wanna measure to make sure it's what you need though. That much damage could of created hest and destroyed your bearing surfaces, and therefore you'd need oversized bearings and a regrind.

King bearings are the current alternative.
<br />Powder coat your block, it looks awesome and is super easy to clean.

Have you found the smoking gun yet? Suspect it was just the HG again?

No clue yet. Seeing how clean everything was, no carbon deposits, I'm guessing coolant got in the cylinder. With the other HG issues though, I never had it run on only 3 cylinders so it must have popped pretty hard.

I think having the block machined once and for all will be the best deterrent to this happening again, I hope at least.

I guess to look at the bright side, my bearings were pretty close to causing a lot more damage so it may have been good to tear it down and take a look. Just glad my crank bearing surface didn't get destroyed. There is basically no damage to the crank surface, comparatively.

Going to have another shop recheck my valve lash while I'm at it as well. I think part of the performance issues is the valve not full closing.

I wish I had someone local I "knew" I could trust.

Just curious, what's up with the #4 sparkplug in the picture of the head?
Looks funny; could just be lighting; could have already been discussed

Haha, didn't notice that, looks like the compression tester adapter didn't unscrew with the hose.

Took the crank to the guy who built my head and had him measure the rod and main bearings. Said it only needed a light hone.
1.9663" on the main bearings
1.7691" on the rod bearings.

So standard ACL/King should work great!