Backstory:

Bought the car with a blown engine. Previous owner stated that it died while coasting to a stop sign in neutral. When they key was turned to the starting position, there was nothing. The starter would try, but couldn't turn the engine over at all. Previous owner suspected an apex seal was lodged in the exhaust port.

But anywho, I got the engine out a while ago and after finding a new motivation to get things torn apart to see what was still intact, I found this tonight:

Turbos removed:


Uh-Oh, this can't be good:


Close-Up of the scary part:


Lets see how much of that debris sticks to a magnet... All Of It!!!!


That is a piece of an apex seal ladies and gents. and all of that smaller debris is also metallic.



So all in all, every speck of that black stuff on the piece of paper is metallic. it all stuck to my magnet. and that larger piece of what is left of an apex seal. One edge of it is worn down to a sharp edge. This little guy was ready.

And looking through the maintenance records of the previous owner revealed that the oil had been changed every 5000 miles, pretty religiously, but still a long tim ein my opinion. Also, the OMP lines have been clear ever since I got the car, which makes me suspect that the apex seals had not been getting any extra lubrication for a while... unless they naturally drain out if the car is left sitting?

 

You can pretty much figure that the housing, rotor and turbos are toast. The sharp edge is the bottom end of the top 3 piece Mazda seal, the rounded edge is what runs against the rotor housing.

As far as the omp lines being clear, could be an issue or not. The motor pulls a vacuum on the lines, along with the pump pushing oil up into them. They can drain back down when the engine is off.

 

Looks like you've got a stud broken off in that turbo manifold too.....they might still be good for a core if you decide to upgrade to BNRs, your rotating assy can be trashed and they can still be used b/c Bryan installs all new larger CHRAs after machining for fitment.

http://www.bnrturbos.com/3rdGen.htm

 

Good catch on the broken stud. PB Blaster didn't work so well. Broke 4 total. Sprayed, let it sit for a while, sprayed some more. sat overnight. sprayed some more. snap x4.

Why do the BNR's require non synthetic oil? I know it says due the carbon seals, but why?

 

Ok, patience and PB Blaster helped me get the manifold off without another broken stud. But I have a couple comparison pictures for you gurus out there. The front rotor is self explanatory. the rear rotor exhaust port is light colored and inside looks BONE dry. Except for the carbon build up on the rotor itself. I could not get my camera inside to get a good picture of what I am talking about, but I figured there would be a little oil, or residue of some sort in the cambers.








What other items may be a culprit to the failure of this engine? OMP? Fuel Injectors? the diffusers were still intact. mileage and long oil change intervals?

Any ideas would be appreciated. I am trying to be overly cautious in installing a new engine. I would hate to install a malfunctioning part, only to lose the new engine.

 

That first pic shows a disgusting amount of carbon build up, whoever owned the car definitely didn't redline it enough most likely.

The rear rotor tends to run leaner due to the uneven LIM, it appears to be the case here.

By the way, I've torn down many engines, and the one pictured is one of the filthiest I've ever seen. Yuck!

 

Was the original precat on the car or did it have a downpipe? What mods? Original or upgraded injectors, stock ecu etc.

 

lol....that looks a lot like mine:

 

I have a quick question... How much does something like this run to fix properly, and is this the most common way that 13b's blow or is it usually not this bad. Sorry for the newb question just trying to get some idea's of what Im in for

 

That's interesting. Is that a common problem for engine failure? And is it more common for the rear to go out first?

 

That one is gonna cost a bit. Looks like you are gonna need new housings, rotors, and turbos to say the least. Basically new motor and turbos.

And every 5000 miles!!!! OMG!!!! I change mine every 2000-2500 miles non-synthetic only.....

Good luck with the rebuild.

 

About $2,000 on the absolute low end using salvage stuff all the way to $6K - $8K using rebuild - new. Turbos alone will run you $500 for a good low-mileage used set to $3000 for a nice new set of ball-bearing units.

These cars....they are NOT for the faint of constitution....lol!

 

THAT is so correct.... hahahahaaa!

I am not sure how big of a hurry you are in to rebuild but in prolly 6 months I will have a set of turbos with only about 5K miles on em that were off an automatic FD originally (manifold is in great shape).

 

Notice the thickness of the corner triangle piece of the apex seal compared to the thickness of the other piece. The other piece looks to be a busted key for the front assembly.

I guess in the later pic it did turn out to be a busted apex seal. Yes I know it would be impossible for a key to work it's way into the combustion chamber, but it does look like a key.

 

^^Holy ****, you're right!! I've *never* heard of that happening either.......

 

So is this the most common thing that happens when they blew or is it usually better or worse?

 

Common but I have seen much worse and I have also taken engines apart that had no other damage other than a chipped apex seal.

 

The rear rotor hasn't been working for some time, you can tell by the carbon...It's been there just for the ride.

 

Clarification on the pictures. the carbon locked rotor is the front. the exhaust port that is whitish is the rear.

here is an attachment that show the maintenance records and when the downpipe was installed. it looks like it had a long life on the stock pre-cat.

Here are the records. there is overlap between each shot, but it will give you a really good idea as to the timeline of this car's life.









I have a feeling I am going to want to service/replace the injectors. Find a way to test the OMP... or run premix. I will start tearing down this engine in a while and posting pics in this thread once I get some spare time.

 

What do you guys think could have caused this failure?

 

That's the 64 thousand dollar question.

 

maybe it was a bunch of things like the 5k oil changes and the lack of redline(the carbon build up)??

 

Lack of redline didn't cause that carbon build up.

 

That spreadsheet is pretty cool. I wish like hell I had started one of those 8 years and 85,000 miles ago when I bought my FD. Of course, the totalled dollar amount would probably make me ill

 

What would cause the discoloration disparity between the two rotors? And that carbon build-up is very extreme compared to the other rotor. is this a large weakness of the stock induction/fueling system? I don't think the PFC can control fuel individually to each rotor. What would be the ideal way to balance this? I am already planning on a dual EGT sensor setup.