legacycentral bbs

Hi everyone I am new here and I have a few questions. I was wondering if anyone could shed some light on cylinder head swaps on the ej22t motor.I have read that some people have used dohc 2.5rs heads on theirs, as others said that it is impossible because the water jackets don't match. I would appreciate it if someone could help me out in this area.Also I would like to know what timing belt would need to be used on this swap?(I am assuming to use a 2.5rs belt).I have also heard of people using sti rods when they are rebuilding their motors.Any help in this area would be greatly appreciated.Thanks

I think the water jacket issues about them lining up isn't as bad as some say....but I don't have first hand experience.

Personally, I'd use the 2.5 SOHC RS heads, if I was going to swap.

I can't remember now what the deal is but i was talking to one of the subaru techs here and he was talking about a difference in a sensors and how it was better to go to the dohc 2.5RS

There are only three timing belts made by Subaru. DOHC, SOHC, and STI.

The DOHC 2.5 heads will lower the compression on the 22t to 7.8 with the thin headgaskets, 7.5 with the thick ones. The water ports are slightly misaligned. Theyll bolt on, but I would recommend porting out the water passages on the heads to line up.

The other issue, is that your gonna need to route water and oil to your turbo, as the turbo heads have all the connections, and the RS heads do not.

Oh ya, your gonna need the intake manifold too, and thats also gonna change your injectors to top feeds, so you'll have to source some WRX injectors.

Basicly if you want to run 2.5 heads you have to use the ej22t block and rs or sti everything else. That also depends on what turbo you want to run. Either way it would be a bad ass setup. This is also my longterm plans.

Thanks for all the help. I was wondering if I needed to match port the water passages.That answered my question. I will start searching the junk yards for the dohc RS heads here in colorado. I am planning on doing porting and maybe going with larger valves. The final issue is what to do with the cams? I plan on running a garrett t3/t4 turbo. I will also be using sti injectors on the motor , and be building my own high flow intake manifold. I will use forged pistons most likely. The one thing I do wonder is what to do about the rods? Are they very tough?Thanks again everyone.

I dont know about the rods but I do know that the RS turbo and non turbo cranks are the same and very solid at that.

Oh ya, your gonna need to swap the drivers side cam gear too IIRC.

around 750000ks now and broke alot of pistons buts still got the factory rods

Subyswamper,
I am in Colorado and have a set of core DOHC Ej25 core heads as well as the intake manifold with fuel rails. You are very unlikely to find a set on a car in a junkyard around here. Trust me. I am a Colorado junyard dog. PM me an offer if you are interested in this stuff...

And a few other comments. See the sticky up top. Xephyr ran the Ej22T w/Ej25 heads for years, did not port match, and never had a problem. And that was a 400+hp engine in his car.

Also, STi rods will not fit in an EJ22T. Different crank journal sizes, but as has been mentioned, the rods are bulletproof. Don't change the damned thing on the bottom end from stock. There is zero point in spending your money there. Save your pennies for rebuildling your heads. Heads are where real power is made...

what would be reasonable price for 2.5RS SOHC heads plus the IM and fuel rails? Or what would yall be willing to spend?

As for pricing, the range is pretty huge. SOHC EJ25 heads go for way more than DOHC. Last time I priced a set at Super Rupair they were $600 a pair, and I get pretty good deals from Dave. DOHC EJ25 heads are more like $400-500 a pair. I paid $200 for my core DOHC heads and $300 for my SOHC core heads. Condition and mileage will make a huge difference.

One thing I forgot in my PM. The heads do have cam gears, but one of the timing belt covers is cracked. I am really only looking to get what I paid for them, including the $50 the manifold cost me...

if i put 2.5l heads on my car do i have to change the cams?

what subaru could i get heads from that would be the best and would not have to change a think in the heads to make them work.

on 2.5l sohc if i got them could i use my factory cam.

Here's the site of someone who's done it over on Nasioc:

http://users.adelphia.net/~wedge138/
(click on technical. At the bottom of the page)

It has some good pics of the comparisons.

I was almost duped by people mentioning that the water jackets didn't match up until I saw these pics. They are so close to lining up as to not really matter.

Yeah,
That's Wedge's site. He did a real detailed write up as he put it together.

NICO,
Your Ej22T cams won't work in any of the EJ25 heads. But if you get Ej25 (or any Ej20 head) complete with the cams, you can drop them right in as is. You will need the manifold, and fuel rails as well. And you will need to address the coolant/oil line issues that Kelly mentioned...

so wrx turbo heads and sti heads would be the way to go, becuse of the oil and coolent lines.

Absolutely, plus the fact that the DOHC heads are solid lifter and will rev higher, flow better than the SOHC2.5 head, and the WRX head will raise compression just a bit. However..........

The WRX cam gear will not work with our ECU. IIRC, the 22T gear has 7 timing marks, and the WRX cam gear only has 2. I'm going to solve this by welding on 5 more marks.

Also, you must use the WRX manifold, which has it ISV built into the throttle body, so you need that too. Plus the injectors, rails, and all that frickin shiz.

Im sure Im forgetting something else.

Oh ya, the WRX manifold has the Tumble Valve Generators as well. So you gotta remove the butterflies from those , however the STI manifold does not have them.

See, I did forget something.

holy shit thats way to much work and money, what is wrong with the factory heads i dont get it, we got 16valves. i have them ported and polished the same factory size of the 2.5s heads.

how about just changing the cams to some crazy spec and makeing it so i can use the factory valves and springs.

crawford makes TGV deletes you can buy.

I make TGV deletes too.

Nico, building a 2.5 head to be comperable to a WRX head would be more expensive than than just buying a whole WRX setups.
(cams, springs, retainers, porting)

And the 22T head, forget about it. 16 valves dont do much good when there pea sized.

Rallitektech,
What on earth are you talking about? SOHC EJ25 heads flow better than WRX heads. DOHC Ej25 heads barely flow better than SOHC EJ25 heads. And unless you have 04+ WRX heads, they still have shims in them, as will all of the DOHC EJ25 heads...

i can bye a hole 2.5l motor sohc with 130ks for 500 bucks, should i get it and take the heads off and put them on my car.

what about the turbo problem with the oil and coolent fluid. will there be a spot to bolt up that thing under the turbo that gets the hot oil and sends it it the motor 3 bolts holde it in.