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Forester S/OBS Parts interchangeable?


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I was recently offered a Foz 2.5s with bent valves for $250. How much can I swap between it and my 99 OBS? I'm thinking struts/wheels/brakes etc. Also, is there any possibility the tranny will ever work in my 5mt driven wagon? At any rate it's in good shape $250 is a steal. Thanks ????

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What year is the Forester?  The '99 Outback will have the EJ25 DOHC engine.  The Forester went to the SOHC engine earlier than any other.

 

While many parts do swap, keep in mind that the Forester is built on the smaller Impreza chassis, while the Outback is on the larger Legacy platform.   Yes, there are differences.

 

Emily

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  • 10 months later...

Bump from the dead, learned alot since I posted this.

Pulled the engine, and the heads off the EJ253 from Forester, they are headed into KC tomorrow to be rebuilt. 16 OF 16 VALVES WERE BENT!!! I couldn't believe it.

Cams will probably be sent to Delta, seems like about the best bang for the buck.

 

I'd sure like to put the 253 into the OBS, seeing that it has 31hp, stock, over the EJ222 thats in it now. If this doesn't end up working out as expected, then the 253 will just have to go back in the Forester.

 

I understand the swap is pretty straightforward, if you're using the intake/sensors/cam and crank pulleys from the EJ222. Still searching the forums currently, hoping to find someone that may have done this specific swap, but I'm about to just tear into it.

 

I think with exhaust and a mild grind I should be able to see close to 200hp at the crank. Not bad for under $1000 (that figure includes the acquisition of the complete Forester) and in the little wagon it'd be a blast. I've spent the last year rebuilding everything else on the car, so as winter comes on, and my work slows, I need something to keep me busy. This is it.  Any advice or criticism welcome, if I'm missing something or not seeing something, chime in. Will keep updated.

Edited by joomanburning
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SOHC forester EJ25 and 99 OBS EJ22 are essentially the same engine. Can swap blocks, can swap heads, can swap engines, intakes. The valves are the same part numbers between the two.

 

You could bolt the EJ22 heads right to the forester block and be good to go and I believe that uos compression for even more cowbell. OBS hS single port heads and exhaust manifold.

 

There are two style trigger marks used for the crank sprocket and drivers side cam sprocket. Keep those with the ECU. In other words - install those OBS sprockets on the Forster engine. Or just look at the trigger points, it's really obvious one has a ton of triggers the other just a couple. If they're the same then no worries. I believe it's an auto/manual difference.

 

Steering suspension driveline (though different final drive ratios) are all interchangeable as well. Brakes are likely different but interchangeable.

 

Not sure you ever mentioned the year of the Forster so we're sort of guessing it's not a 2015. Lol!

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The Forester is a '99 as well.  As far as the frankenmotor goes, I'm all for it.... but maybe you can help clear this up for me- it seems there is a bunch of confusion across the boards....

 

Don't I need Phase 1 EJ22 heads for this to bump compression? I thought I saw a spec sheet somewhere that said Phase 1 Ej22 heads were 41cc and the Phase 2 EJ22 were 50cc, which is the same as Phase 2 EJ25...?

Of course, I can't find the link where I read that when I need it.

 

Either way, I'll probably just put the heads back with their respective blocks, for now. :blink:

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I'm unfamiliar with the EJ22 heads but you're probably right - they're the same intake manifold, same valves, basically the same exact heads except for the single port exhaust, so yeah you're probably right, the Phase II heads may be identical. 

 

Phase I heads won't accept the Phase II intake manifold so you can't bolt the Phase I heads up without annoying issues to resolved, customize, work around. 

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What year is the Forester?  The '99 Outback will have the EJ25 DOHC engine.  The Forester went to the SOHC engine earlier than any other.

 

While many parts do swap, keep in mind that the Forester is built on the smaller Impreza chassis, while the Outback is on the larger Legacy platform.   Yes, there are differences.

 

Emily

Original post said OBS, which is Outback Sport, which is an Impreza, not a Legacy Outback. So, I think both built on an Impreza chassis . So, lots is interchangeable.

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I didn't own the EJ25 while it ran, but the previous owner claimed there were no issues aside from the broken timing belt.

Seems to rotate free and fair, although there was a slight bit of rust on the cylinder walls, however it doesn't feel like it pitted at all. I wiped it out, coated with oil and hand rotated 50 times or so.

 

On a side note, as if by some kind of mechanical divine intervention, the clutch fork gave way to the pivot ball on the OBS Friday afternoon, so the EJ22 is out. Luckily, the guy before me replaced the clutch, and he either didn't tighten or left off the pesky bottom driver side bell housing nut. Parked it, and had the motor out in just under 2 hours. I think I may rebuild the EJ22 from the bottom up for boost....

 

The EJ25 will be getting the EJ22 intake, appropriate cam/crank sprockets and flywheel (EJ22, 25 share flywheel) an EJ25 clutch kit, then dropping it into the OBS as soon as the heads and cams are done. Since it was a timing belt failure, I'll go ahead and have the block deck checked and trued up.

 

What do you think- go ahead and replace rod bearings?? Or don't fix what isn't broke?? The EJ25 lived a pretty mild life aside from the belt failure. I guess I could build this block for boost too, but the car is my DD so I need to get something on the road. I know I'm kinda rambling at this point....

 

The throw out bearing that was on the shaft was sleeved. Should I go ahead and re-sleeve??  The quill didn't look too ate up, but I don't have an O.D. caliper to measure. My dad was a truck mechanic for 40 years, and he wasn't even sure about this little sleeve.

Edited by joomanburning
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