Any issues with Subaru engine?
 

Just curious if there are any issues that should be resolved by aftermarket reenforcements with the subaru engines?

Like are there leaky valves that tend to fail?

Haven't heard bout leaky valves... but I heard here and there, but burns the oil. For me, I need to put bout 1/3~1/2 quart every 1.5k miles or so.

There have been some problems with the strength of the pistons in high-powered EJ25's - including some stock STI's - that can be completley solved by getting forged pistons.
No catastrophic failure happens, but they will lose compression and thus make less power than they should. Often, the owner won't notice anythign until the enigne gets a compression test or rebuild.

They don't come stock because it's harder for Subaru to get cold-start emissions with forged pistons.

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The early 265hp WRXs (09 model year) had some problems with owners blowing the engine (main bearing failure) even before the break-in was over. This was a manufacturing defect and has been resolved.

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Otherwise... newer EJ's are "interference" engines - if you go way past the timing belt change interval and it fails, you need a new engine.

Mainly if you keep up with preventitive maintenance and have good synthetic oil, even a modified EJ should be running strong for a solid 200k.

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@Ichitaka - really? I burn very, very little oil - even having the turbo - I don't think I've ever had to add oil inbetween intervals. Granted my car is pretty new... but I've never heard anything about latent oil loss like you describe. Time for piston rings / maybe a small leak?

Sorry, I should of been more specific on that oil burn.

No, I've overhaul my engine last yr (including piston rings) and there's no leak (after overhaul, I let the pro check for any leak). You're forgetting that your engine is DOHC with better technology than mine (SOHC). technically, my engine is 80's technology vs yours 20th century technology. If I don't race my car often, then I actually don't need to put any oil in my car (winter time, no adding oil at all)... so pretty much cause by racing.

no major issues on new engines. they used to have head gasket leaking issues, but i haven't heard about anything like that on vehicles newer than '01. i've heard some stories about bearing problems, but i don't think it's a common occurance.

which bearing? Wheel hup bearing or crankshaft bearing? Either way, you're right. New vehicles engine been taken care of. Oh and it's not newer than '01, but '04 or new ones. '02~'03 wrx head gasket & crankshaft bearing were one of the problem they had (iirc).

so you're saying if I buy a car with a subaru wrx engine in it...

it would be a good thing to change my pistons to Forged Pistons as a first modification?

It's for you to judge & decide... but if I was you, if I need to change out the pistons to forged pistons, I'll do full blown internal work while at it (crank, valves, cams, port, bore, & etc). It'll be waste of money just only to get forged pistons in. Anyways, you gonna take out the engine out, mind as well.

Another thing if you happen to pull the engine, check your plugs while you are at it. I dont have any personal experience with boxer motors, but from what I hear, they are a real pain to get at.

plugs? Like spark plugs? Spark plug isn't hard to get to. Driver side is lil bit pain, but still 200x better than '00 Montero Sport (got to take out effin' intake manifold to get to the damn spark plugs).

Plug aren't that bad - yes, they're a pain especially if you're used to an easy-to-reach inline 4 - but very doable.

I wouldn't do forged pistons as a first modification, especially on a (non-STI) WRX. But be prudent with compression tests when modifying a '25.


With the explanation, ichitaka, I gotcha.