Looking for some EJ25D info.

[Perkul8r]

Ok. So I have been doing my best to search and search to find a for sure answer on my question. I have a 99 legacy SUS with the EJ25D. From what I have read this should have a Phase 2 shortblock in it.

Now, my question is. I have a buddy upgrading his internals in his sti with the EJ257. And have been trying to find out for sure if the internals will work on my motor...If so, I want to grab them while I have chance.

Sorry if this has been answered, I have been searching for a while and can not find a clear answer.

Thanks for any info,

[86bratman]

I can't swear that it's ever been done with a 99 dohc, but it has in the sohc phase 2. Do some maths to see where your compression ratio will come out to be. You will probably be higher than stock sti because the 97-99 heads have a smaller combustion chamber if memory serves.

[r3v_v3ng3]

I think most 99 25D have the hybrid block. Basically phase 2 block/crank/rods and pretty sure it uses the phase 1 design pistons which is the big square indent. The piston have 2 dots on it while the non hybrid 25d have 1 dot.

Count how many nuts/bolt the engine is connected to the tranny. The phase 1 only have 2 nuts/ 2 bolts. While phase 2 have 2 nuts and i think 6 bolts.

If you have a phase 2 block then yes the sti rods/pistons will work on the block. Check out my build thread on my BD which I did the same.

[Perkul8r]

I think most 99 25D have the hybrid block. Basically phase 2 block/crank/rods and pretty sure it uses the phase 1 design pistons which is the big square indent. The piston have 2 dots on it while the non hybrid 25d have 1 dot.

Count how many nuts/bolt the engine is connected to the tranny. The phase 1 only have 2 nuts/ 2 bolts. While phase 2 have 2 nuts and i think 6 bolts.

If you have a phase 2 block then yes the sti rods/pistons will work on the block. Check out my build thread on my BD which I did the same.

I tried to take a look at my car, but I think its only a phase 1. Its an early production car, build date was 02/98.

I read somewhere that the thrust bearing was in a different spot on the phase 2. Do you happen to know where that is on a Phase 2?

I am only asking cause I was hoping to use my current motor. But I think mine is a no go. So I want to pick up a block from a buddy, but motor is already out.

[86bratman]

Easiest way to tell is to look at the bellhousing, phase 1 has two studs on the bottom down by the axles, and two bolts at the top corners, phase 2 has the same two lower studs and 6 bolts along the bellhousing.


phase 1 has the thrust bearing on main #3 and 48mm rod journals, phase 2 has the thrust bearing on #5 and 52mm rod journals

[Perkul8r]

Easiest way to tell is to look at the bellhousing, phase 1 has two studs on the bottom down by the axles, and two bolts at the top corners, phase 2 has the same two lower studs and 6 bolts along the bellhousing.


phase 1 has the thrust bearing on main #3 and 48mm rod journals, phase 2 has the thrust bearing on #5 and 52mm rod journals

I already tried looking at mine as I stated in my last post. And I do believe that I have a phase 1. However, I found a guy that will sell me a phase 2 block, STi crank and STI rods for $100.

[r3v_v3ng3]

I'd be all over that deal :shock:

[Garrison]

Seriously! Dang, some guys have all the luck.

[Perkul8r]

Seriously! Dang, some guys have all the luck.

Well...luck wasn't on my side. lol. Sadly, had to put new valve cover gasket, plugs and wires in the gf's 04 LEgacy, so there went my motor money. But at least now I have the info I need.

Thanks guys.

[Garrison]

Seriously! Dang, some guys have all the luck.

Well...luck wasn't on my side. lol. Sadly, had to put new valve cover gasket, plugs and wires in the gf's 04 LEgacy, so there went my motor money. But at least now I have the info I need.

Thanks guys.
If you're passing on the offer, may I have his contact info?

[Perkul8r]

I'll see if he still has the stuff.

[lord flashheart]

idk if you already got the answer to this, but the STi rods are shorter by about .060 if i remember right, so you would need to swap the pistons too, and the pistons should be honed to the correct size which since its standard, wont work. the crank shaft is the same. the other stuff is also the same like the connecting rod housing bore and wrist pin bushing and all that.

[Perkul8r]

idk if you already got the answer to this, but the STi rods are shorter by about .060 if i remember right, so you would need to swap the pistons too, and the pistons should be honed to the correct size which since its standard, wont work. the crank shaft is the same. the other stuff is also the same like the connecting rod housing bore and wrist pin bushing and all that.

Please tell me more about how the pistons would not work? I am not quite understanding this. From all the reading I have done, sti EJ257 is a 2.5. Phase 2 2.5. Same bore, or am I missing something?

[r3v_v3ng3]

Just make sure you use the corresponding piston A or B to the block

[Perkul8r]

Just make sure you use the corresponding piston A or B to the block

How would i find out which one a block is supposed to have? Seems like I would be buying a 2.5 block with crank, than sti pistons and rods. So if there are no pistons currently in the motor, how can I tell what pistons are supposed to be in there.

[86bratman]

the letters are stamped into the block, right behind where the alternator would be, look for a perfectly flat section where the block halves meet. May have to clean it off but they'll be there.

[Perkul8r]

the letters are stamped into the block, right behind where the alternator would be, look for a perfectly flat section where the block halves meet. May have to clean it off but they'll be there.

Awesome..Thank you. See this is the stuff I wasn't able to find in my searching. Most people were like "just throw a set in, it dont matter" Lol.

Thanks for the info guys.

[Perkul8r]

Seriously! Dang, some guys have all the luck.

Well...luck wasn't on my side. lol. Sadly, had to put new valve cover gasket, plugs and wires in the gf's 04 LEgacy, so there went my motor money. But at least now I have the info I need.

Thanks guys.
If you're passing on the offer, may I have his contact info?

Hey man. I talked to him and he's gotta wait a bit now to build the motor like he wanted. They had some issues with his house, so that comes first.

[86bratman]

Tolerances are close enough that you can get by with any set, but personally I'd rather not chance it. Building my high comp dohc ej22 I bought three sets of svx pistons before I got the 4 b's I needed.

[lord flashheart]

Using used pistons in a different block is pretty frowned opon.
The engine is the same bore which is 99.5 mm which is about 3.917 inches. But measuring down to a thousants of an inch isnt precise enough so we measure down to 1 ten thousants of an inch. So you may have one that is 3.9179 and another that is 3.9171. Subarus needs roughly 0.0008 inches of clearance. So if you put the pistons in there willy nilly some will be loud and clatter down the bore and the others will be too tight and destroy the bore and pistons.
So if you are determined to do it you need to messure each piston and bore at aproximately 70 degrees F. Then assign pistons to bores based on what the clearances will be. Also you should hone the bore and use new rings because the rings have been broken in and so has the bore. So if you dont put new rings and home it it may cause oil consumption issues. Remember to set proper ring gap.

[Perkul8r]

Using used pistons in a different block is pretty frowned opon.
The engine is the same bore which is 99.5 mm which is about 3.917 inches. But measuring down to a thousants of an inch isnt precise enough so we measure down to 1 ten thousants of an inch. So you may have one that is 3.9179 and another that is 3.9171. Subarus needs roughly 0.0008 inches of clearance. So if you put the pistons in there willy nilly some will be loud and clatter down the bore and the others will be too tight and destroy the bore and pistons.
So if you are determined to do it you need to messure each piston and bore at aproximately 70 degrees F. Then assign pistons to bores based on what the clearances will be. Also you should hone the bore and use new rings because the rings have been broken in and so has the bore. So if you dont put new rings and home it it may cause oil consumption issues. Remember to set proper ring gap.

Thank you for the detailed info.

I will say I always use new rings at least. I've learned from my buddy's mistakes on not doing this. And I usually have the blocks finished honed at the machine shop. I will be honest, I didn't know Subaru's were this picky. I know the ej25d currently in my 99 slaps pretty good in the upper rpms, it actually sounds really bad so I just baby that thing around.

[lord flashheart]

Yea because the skirts are so short the clearences need to be right on the money otherwise they will make noise or gouge the cylinder walls. Also usually piston slap occers in lower rpm and disappears in uper rpm because the centrifugal force keeps the piston against the trust wall. And goes away when warm.. might not be piston slap...

[Perkul8r]

Yea because the skirts are so short the clearences need to be right on the money otherwise they will make noise or gouge the cylinder walls. Also usually piston slap occers in lower rpm and disappears in uper rpm because the centrifugal force keeps the piston against the trust wall. And goes away when warm.. might not be piston slap...

Hmm...I wll try to get a video of it. it has some noise on startup, goes away once warm, but it you hear a noise in the upper rpms. Cruising around town you dont hear it.

[lord flashheart]

Could be valve ajustment. Who knows haha.

[Perkul8r]

Could be valve ajustment. Who knows haha.

Oh my..I kinda feel stupid. lol. I bet it is some sort of valve noise. See..when i got the car, one of the timing belt idlers had messed up. So it threw the timing belt. I put a new timing belt kit in it, already figuring heads where shot. Put it together enough to try and start it, i didn't have access to a compression tester at the time, and well....it fired up. lol. And I have been driving it since. I am pretty sure there is no way the motor escaped all harm when the timing belt slipped. But the car runs good. Does have a very slight miss though.