Cylinder 4... she gone

Hi team!!!! I’ll try to make this short. My wife has a 2012 legacy GT turbo 6 speed. Recently check engine light came on and I got the awesome cylinder four misfire PFEEE. So I did the plugs swapped the coil started her up, still had the cel, ended up doing a compression test, showed 25psi on 4 and leak down showed air coming out the crank case. I can be pretty sure I have ringland failure. But not to worry because I have an STi 2011 that I want to build. So, my goal is to replace the bottom end of the legacy 2.5 with the bottom end of my ej 257 out of my STi, slap on the heads, oil pan, turbo and get the 257 all dressed up. The legacy has 165k on the clock, not sure just replacing the ring is worth it, my STi has 78k on the clock and I think that’s worth putting in the wife’s car, plus, I can justify building out my lower end. Now only issue I have is... will this work? I know these legacy’s are the bastard child and not popular, which is what I like about them. I know so many parts of Subaru’s fits other Subaru’s, but is the ej motor in our legacy’s different than the ej257? Any thoughts or provoking questions are more than welcomed.

I believe there is an extra bolt hole in the sump for the 5th gen block (which I don't believe is a big deal).

 

Maybe others can confirm if anything else on the short block would be an issue.

really make sure that it's the ringland and not a burnt valve, which seems like it's a bit more common on these, before you commit to removing the block from the STi

The pistons are also different. The 5th Gen has 9.5:1 compression which is higher than the other EJ255 and EJ257. Owners have put lower compression STI short block (and rebuilt them) though.

 

Is your Wife's '12 GT Modified? You have to figure out why the engine is running lean and caused the ringland to failed.

Not what I was expecting in this thread. Looks like a few forums were hit.

i'm surprised such a niche forum got hit

Fixed the glitch, or at least started on it.

 

 

Also, to add something of value, I'd echo the suggestion to see if it's a burnt valve.

I believe there is one extra bolthole on the 5th gen and one that is larger since it uses an oil pan adapter. Otherwise, it does bolt up to everything else.

 

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Thanks everyone. Yeah I did hear air coming from the oil fill during the leak down. The car is not modified and is up to date on maintenance. In my opinion by looking at the plugs I thought the car was lean, but then I was like, it’s not modified in any way, so I didn’t think much about it. Now with the extra hole in the block, do I just need to fill it with a bolt or something, assuming it’s threaded? With the compression being lower on the sti bottom end and legacy heads, my thought here is get a tune and turn up the boost to get the loss in power back? I don’t want to put a ton in performance into the car, but if I did a down pipe, and had 8.5:1 compression maybe a tune will bring it back to the 260-280 horsepower range? Thanks for all the information and questions.

165K before failure? that's pretty good... you are going to have to tear it down and inspect for damages anyways so might as well remove it from the car.

so i was wrong and it turns out to be a bad valve. Cylinder 4 exhaust valve is smoked, probably 25% missing. looks like the car was running a bit lean. so i am going to drop the heads off at the machine shop and the dude says he will get me a price to fix them later to day. well hes telling me 350$ a head plus parts, guides are 20$ each and an exhaust valve is 79$ for an awesome total of over 1100$ with taxes. so, is there something here i am not under standing? price seems insane. If this is the case, will wrx heads, forester XT heads, or any other head outside of an STi work on our cars?

so i was wrong and it turns out to be a bad valve. Cylinder 4 exhaust valve is smoked, probably 25% missing. looks like the car was running a bit lean. so i am going to drop the heads off at the machine shop and the dude says he will get me a price to fix them later to day. well hes telling me 350$ a head plus parts, guides are 20$ each and an exhaust valve is 79$ for an awesome total of over 1100$ with taxes. so, is there something here i am not under standing? price seems insane. If this is the case, will wrx heads, forester XT heads, or any other head outside of an STi work on our cars?

 

I paid $1050 with all new valves for both heads. I was a little surprised because I had seen other owner play $500 at machine shop to repair and redo the valve lash. It wasn’t until I priced out the parts that I realized that those shops are only replacing the damaged valve.

The 5th gen uses an E25 head with is unique to this generation. The no other ej25 head is going to have the provisions on the passenger side head for oil pump for the turbo sump pump.

when i had my head gaskets done the machine work(including resurfacing fly wheel) came out to $750, so $350/head doesn't sound extremely high to me. lot of work and they've got to do everything twice...

Our heads are specific to our engines, so you are stuck. You can't compare your charges to what you read unless you know exactly what was done. I paid $600 for shims and lash setup on my new heads.

 

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