What caused my later model EFR6258 to die?
 

Car has been running fine aside from some blow-by I've been noticing. Car smoked upon startup only after sitting overnight, but would stop as soon as it was warm. I drive home tonight and half way into my commute, car stops boosting. I hear a faint howl and think boost leak. No leak, tears or holes were found. I looked into the inlet and and turbine and my heart dropped. Everything rotates freely, but the shaft appears bent, possibly due to turbine fin throwing everythign off balance at such high [turbine] rpm. The air filter, while dirty, was intact so I don't think it ingested anything.

Now I need a new turbo and a new motor (or rebuild). Give me a reason why I want to keep this miata.


https://www.miataturbo.net/attachmen...921_210141-jpg

https://www.miataturbo.net/attachmen...921_214523-jpg

ouch. sorry man.

tb screw ingested possibly?

good call, i'll take a look tomorrow (though I've never had them loosened on my watch)

Any updates?

Did you check the CHRA bolts on the turbine side?

CHRA bolts are snug, but can be hand loosened. The spec is 10 ft-lb

Took some images. Not too sure what happened. I don't think it was bearing failure. Shaft spins fine, no resistance, but it is warped a bit (I believe from misbalance after turbine fragged).

Full-Race said they cannot warranty this since I'm not the original purchaser. Shucks. Learned my lesson

Disassembled the turbo
https://www.miataturbo.net/attachmen...34482719_n-jpg

Wastegate bracket was only held in by a coolant banjo fitting. The head broke off, the other screws backed out
https://www.miataturbo.net/attachmen...36019571_n-jpg

Turbine Carnage #1
https://www.miataturbo.net/attachmen...82860757_n-jpg

Turbine Carnage #2 - Look, the base of the wheel had broken off. I wonder if this got stuck while trying to exit, damaging the rest of the fins at speed
https://www.miataturbo.net/attachmen...52736802_n-jpg

Turbine Carnage #3
https://www.miataturbo.net/attachmen...77167840_n-jpg

Tiny amount of weeping on the rear oil seal. I attribute this to high oil pressure on cold starts (~85-90psi). Full-Race says it's fine as their customers operate these turbos at 100psi, far over BW spec. When warmed it doesn't see over 80psi oil pressure on full tilt.
https://www.miataturbo.net/attachmen...41449986_n-jpg

The shaft spins freely, but has a wobble to it now. Barely noticable play axially, zero radial play. Here the compressor wheel crashed into the backing plate a bit
https://www.miataturbo.net/attachmen...88600546_n-jpg

The compressor wheel touched down on the housing.
https://www.miataturbo.net/attachmen...00503527_n-jpg

Basically, I honestly cannot definitively say what happened other than the turbine is shot. I don't know when the onset of failure occured, I just noticed when it became catastrophic enough to affect every day driving. I cannot find my snap ring pliers to remove the bearing section and inspect. Will update later.

This turbo won't be warranteed, so I need to decide if it's worth getting a super core for $1100, replacing the center portion and reusing my housings, or if I should just eat an extra $400 and get a new turbo (with a warranty) that will have all the correct tolerances on the compressor side.

EFR6258 or EFR6758 on pump gas? Thinking sticking with the 6258...or getting rid of the Miata. I've bled a lot into this project already.


.....or Bauer catfish

Did you inspect the throttle body? My 2560 lost one at Laguna and the damage is somewhat similar:

https://www.miataturbo.net/prefabbed...e-wheel-81058/

--Ian

Throttle body bolts on the butterfly are both still there. I guess I'll take the head off and see whats inside

With the aluminum shaved from the compressor housing, should I be thinking about replacing my intercooler and washing out my charge piping?

Full Race can at least take it for inspection, that's a dick move to deny it straight up.
Does look like it ingested something, though.

They kept pushing that it's likely contaminated oil that caused bearing failure. They don't want to see the turbo since they aren't going to be able to offer me anything other than selling me another product due to warranty not being transferable.

I'm going to built another motor and swap it in eventually. I don't quite trust the motor currently in the car. I might also have my BE oil pump sent back and inspected.

Replace intercooler or leave it?

Sorry to hear all this, man :( Don't give up the fight!

Just ordered internals for a 94 block. It'll be nice to shorten the oil and coolant feed to turbo. I need a crank though. Pulling the head this weekend.

You are one boss dedicated man.

Couldn't you re-use some of the old internals, like rods and pistons?

Best of luck man. Wow.

I figure for as tapped out as this setup is, I think it's best to have a whole motor ready to drop in at any given time. That way when I pull the old one out, I'll start assessing and re-rebuilding. Worst case I throw it into a catfish or exocet.

Having just eaten the no warranty sandwich, I would certainly get a new one. Especially on a piece like this and if a core alone is $1k!

If you stick with the project (please do) then don't shoot yourself in the dick. God forbid things go sour later, because then you might be so pissed off from the second failure with no warranty that you actually shoot yourself in the dick. Worth $400? It probably is even for the peace of mind after this ordeal.

Yea, there are some parts where the assurance of a warranty is worth the extra cost. Though in this case I don't think it was a manufacturer defect. Speculation is something got ingested and pooped out the turbine.

Last try. If it dies again, with a new motor, I'm definitely doing something wrong and should quit and take up baking.