I am trying to figure out if this is an internal issue, or a head gasket issue. 1 year old motor, daily driven. This is the woman's car, she reported stalling at stops and random misfiring, and an instance of the AT oil light flashhing. The whole time we have owned this car, the airbag light has remained on, but it went away for a moment while acting up. The stumbling issue has been random, not always reproduceable. So i thought i would swap out the MAF to discoer this:

 

 

The only thing I can come up with is cracked piston sleeve or shattered ringland.

 

When I shattered the #4 piston in my 07 wrx, I made the same hole in the piston joke. It was denial manifesting as humor lol.

I see a leak down test in your future. There are kits for testing CO in the coolant available as well. Either way it appears the culprit is internal.

Broken ring land race car dose that when piston is broken between the comp rings needs piston! I have boxes of them

I'm curious as to what it turns out to be.
 
In my experience with tuning my frankenmotor I found the timing using the stock EJ22E ECU to be much too advanced, even running premium fuel.  Not sure anybody heeded my warning though. 
 
http://www.ultimatesubaru.org/forum/topic/129946-frankenmotor-and-ecu-hacking/

Edited March 11, 201412 yr by presslab

I'm not sure this is a HCF (aka frankenstein), I think Fox was just referring to how it was running.

 

Note to get OT, but you could run thicker head gaskets to bring the HCF compression down a touch. Or hell, just go e85.

This is a 97 outback ej25d block with 95 legacy outback ej22e heads running in a 98 forester, which ecu is original to the original ej25d which this engine replaced.

 

I have the original ej25d engine form the forester with bad hg's that i intended to put together. I have decided to replace this engine in the forester with a stock ej22e from a 96 legacy as a cost effective immediate fix, and then once i have parts, build the other engine to replace the legacy motor with all the goodies. For now, the legacy is retired and i transferred the plate onto my 3door so that i have a legal car and an engine for the forester.

 

for those of you who have seen my 'art of subaru maintenance: ej series' vids, this is the motor used in the videos. This engine did have rusty cylinder walls when it was assembled, and i blame the failure on that plus going back and forth between low octane gas (woman driver)

I'm not sure this is a HCF (aka frankenstein), I think Fox was just referring to how it was running.

 

Note to get OT, but you could run thicker head gaskets to bring the HCF compression down a touch. Or hell, just go e85.

Speaking of compression, as to build up another clone to this engine, i sourced some part numbers from subaru dealer. all of the 2.5's list one part number , which is superseded by another part number (11044AA633, and then there is the 2005 sti gaskets and its part number (11044AA642. which ones should i consider? my failed engine has cometic hybrid gaskets.

 

Come to think of it, i never considered ea85. I would have to go across the other end of town for it. I don't know if the fuel injectors and fuel lines will like it, though. The forester has over 250,000 miles.

Ahh so it is an HCF, cool!

 

I know many WRX's running e85 with no problems with the fuel lines/gaskets/seals. Its great for detonation prevention in addition to ~30% more power/less mileage.. But would likely need to play with injector sizes and maybe a bigger fuel pump.

 

The ej25 head gaskets can block coolant passages in the 22 heads, use the cometic hybrid gasket. Part# H1631SPK040S (.040). Hopefully this is the gasket you were running before.

Rust on the cly walls good luck sealing

Rust on the cly walls good luck sealing

 

Ball hone!

I'd guess the EJ25D ECU would have somewhat lower timing vs the EJ22E one.  I looked for a ROM for that ECU so I could look at the timing but I didn't see one out there.  But not running premium!  There you go.  With the ECU already pulling the timing because of the higher compression ratio, there is no room for error.

 

I'd say the rust on the cylinder walls would reduce compression slightly...  I've never heard of rust causing catastrophic blowby though.  Seems like it would be more of an oil consumption problem.

 

Cometic can make that hybrid gasket in lots of different thicknesses, can't they?  I used the Subaru MLS EJ25D gasket and I had to drill out the passages.  What a PITA.

I'd guess the EJ25D ECU would have somewhat lower timing vs the EJ22E one.  I looked for a ROM for that ECU so I could look at the timing but I didn't see one out there.  But not running premium!  There you go.  With the ECU already pulling the timing because of the higher compression ratio, there is no room for error.

 

I'd say the rust on the cylinder walls would reduce compression slightly...  I've never heard of rust causing catastrophic blowby though.  Seems like it would be more of an oil consumption problem.

 

Cometic can make that hybrid gasket in lots of different thicknesses, can't they?  I used the Subaru MLS EJ25D gasket and I had to drill out the passages.  What a PITA.

 

Yep, they can make any thickness you want with that hybrid gasket.

Edited March 12, 201412 yr by Ibreakstuff

1. I had used the cometic hybrid gaskets on this one. I have matched both he original ej25d and ej22e head gaskets to know where to make the hole to modify an oem gasket for this application.

 

2. I will not be re-using the ej25d block with the rusty cylinders. I have another complete ej25d original to the forester for a block. I will be re-using the the ej25d heads.

 

If i put this frankenmotor together again, i might as well swap it into my legacy, and use the legacy 2.2 engine in the forester for the woman. I will likely consider modifying an oem gasket if there is a preferred one for the application, unless i can re-use the cometics, and i have also heard about cometif gasket failures. Perhaps the hg failure is just an ej25 thing by itself.

Cometic Gaskets:

 

This motor built:

+1 on using exhaust for leverage, I now know how you were shearing those axle pins..
+2 on the turning bolts without opposable thumbs, #*(& darwin