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-   -   Name that expensive noise (https://www.miataturbo.net/engine-performance-56/name-expensive-noise-98511/)

curly 11-22-2018 03:44 PM

Heads fine as long as everything including galley plugs are removed and cleaned, assuming the cam journals are ok. Grind the crank and use some over sized bearings. Disassemble and clean all the vvt pieces, they can all be disassembled 90% more than you’d think. Only thing you can’t salvage is the oil/water cooler. This all changes if you choose to continue to run it like some idiots.

wackbards 11-22-2018 03:53 PM

Ok, that gives me some hope. I had the short block built at a shop, so I guess we'll have a conversation about the rebuild.

I have put probably less than 25 miles on the motor since noticing the onset of the noise basically just trying to diagnose the noise.

18psi 11-22-2018 04:05 PM

Take it apart really slowly and carefully and inspect it like you've never inspected anything in your entire life. With spun bearings the likelihood of clogged passages is so high, and I've seen way too many re-rebuilt engines die again exactly the same way due to hidden issues.

Bummer it died so quickly.

shuiend 11-22-2018 04:25 PM


Originally Posted by wackbards (Post 1512203)
Well, I pulled the valve cover, aaaannnnnd... The oil is all kinds of gold and sparkly. Spun bearing.

So... Learn me about what I can do. What parts of this motor can be salvaged, and how do I clean what I can keep?

Follow these steps.

1. Go inside and get a bottle of liqueur.
2. Take several swigs from bottle.
3. Cry.
4. Go to step 2 and start again from there.


Loosing built motors sucks I am well aware of how you are feeling.

wackbards 11-22-2018 04:37 PM

I have another VVT actuator, and an entire extra valve cover, so I can more or less just swap the VVT stuff over. I have an extra crank too. I hear crud can be almost impossible to get out of the crank journals. That would be mostly just be annoying because I had the rotating assembly balanced.

So here's my thinking:

Tear down the head, and check cam journals to see if they're still good. If they're still good, uncork the oil journals and hot tank it. Put it back together with the extra VVT bits I have laying around.

For the bottom end, inspect the crank, journals, and rods for damage. Pull all the galley plugs on the block, and get it tanked. If the crank is still good, how do you clean the crank galleys? Am I better off just using my spare crank and getting the rotating assembly rebalanced?

Also, as Curly mentioned, I'll need to get a new oil cooler.

Anything I should do to the oil pump?
Should I re-hone/re-ring?

shuiend 11-22-2018 05:18 PM

New rings and re-hone anytime pistons are out and the motor has run before.

curly 11-22-2018 06:12 PM

Haven’t done it myself, but I’ve heard the ball bearings in the crank can be removed, taped for npt, obviously cleaned, then plugged.

The vvt stuff is all very easy to disassemble and clean, no need to replace. Just invest ~$100 in brake clean.

wackbards 11-22-2018 06:34 PM

I have a parts bath that I plumbed a giant oil filter into, and 10 gallons of mineral spirits, so minimal brake cleaner required. I'll just swap the VVT stuff for known good since I have it, and it gives me peace of mind.

The real question next is how much damage has been done.

Ramonn 11-22-2018 07:28 PM

Damn so it was an expensive noise after all :(

What I wanna know about that spun bearing... How could he have avoided this? Is it even certain that there was an assembly mistake?

Really curious

Anyway, gl man. Don't drink and cry, keep wrenching!


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