Ej25D DOHC to EJ253 SOHC Swap

[jnorth85]

hey guys!

i recently purchased a 98 Forester. the catch is that it has a blow motor (yup head gasket) anyways i happen to have a spare 00 SOHC laying around and i want to swap this motor over. i realize from searching there are a few problems doing this.

 

my question is this.

 

what if you swap the manifold and everything from the heads up?

 

yes i know it wont bolt up. but what if you made a .5" adapter plate? that would bolt on to the SOHC heads then adapt the DOHC manifold?

 

This would solve 90% of the problems correct?

 

all you are left with at this point is the crank/cam sensors then one could just splice the wiring and you are done!

 

any comments/thoughts on this?

[mcbrat]

Welcome Justin

 

Interesting thought there on the manifold adapter. If that would work, could be a marketable item....

[jnorth85]

Welcome Justin

 

Interesting thought there on the manifold adapter. If that would work, could be a marketable item....

 

Thanks!

im just trying to find an alternitive to doing a hybrid SOHC with DOHC heads or what some of the others have done and adapt the DOHC wiring harness to the SOHC intake manifold.

[mcbrat]

there's actually more talk about these kind of swaps in the New Gen forum....

[jnorth85]

there's actually more talk about these kind of swaps in the New Gen forum....

 

Ill have to cruise on over there and do some reading.

[mcbrat]

I moved this to the new Gen.

[idosubaru]

i would check and see how hard it would be to install the DOHC engine harness onto the SOHC intake manifold. that might be simple.

 

the issue would be with the cam, the sensors are likely different. if the cam sprockets are identical in shape and fitment then you can just swap cams...i know you can do this with other engines, but being the DOHC to SOHC swap that gets tricky.

 

on some engines you can retain the cam sprocket that was originally in the car.....but with different number of cams that sounds complex. but i'd look at them at least. it might be that that cam sprocket where the sensor is, is the only one that needs replaced, since it should have the proper pick up marks on the back of it that tell the sensor it's position. that's what the ECU needs, the proper signal.

 

so the DOHC cam sprockets installed on the SOHC engine...dropped back into the DOHC vehicle.

[NOMAD327]

Just curious, isn't the 2.2 in place of 2.5 swap that most people do a DOHC to SOHC swap?

[idosubaru]

Just curious, isn't the 2.2 in place of 2.5 swap that most people do a DOHC to SOHC swap?

yep, sure is.

 

the later motors though do incur changes and differences, so it might not be quite that simple dropping a 2000 into a 1998.

[subaru360]

hey guys!

i recently purchased a 98 Forester. the catch is that it has a blow motor (yup head gasket) anyways i happen to have a spare 00 SOHC laying around and i want to swap this motor over. i realize from searching there are a few problems doing this.

 

my question is this.

 

what if you swap the manifold and everything from the heads up?

 

yes i know it wont bolt up. but what if you made a .5" adapter plate? that would bolt on to the SOHC heads then adapt the DOHC manifold?

 

This would solve 90% of the problems correct?

 

all you are left with at this point is the crank/cam sensors then one could just splice the wiring and you are done!

 

any comments/thoughts on this?

 

Ok lets say you could get the '98 intake on the engine. You are still left with a major problem in that the trigger wheel for the cam sensor is totally different and there is no solution for that.

 

You'd be better off either fixing the engine in the car or picking up an EJ22 to swap in, or putting the shortblock from your spare engine you have in if the heads on the on in the car are still good.

[mellow65]

Ok lets say you could get the '98 intake on the engine. You are still left with a major problem in that the trigger wheel for the cam sensor is totally different and there is no solution for that.

 

You'd be better off either fixing the engine in the car or picking up an EJ22 to swap in, or putting the shortblock from your spare engine you have in if the heads on the on in the car are still good.

 

that's not true the trigger wheel worked when i swapped a sohc ej25 into my 90 legacy.

 

 

here is the true answer because i did this swap, kind of. i put it in place of a 2.2 in a 90 legacy. but if you have stuck around long enough you should know that the 2.2 is a easy swap for the phase 1 ej25 so the same stuff holds true with the phase 1 ej25.

 

if you could make the adapter that would take care of 99% of your stuff. take your crank sensor and cam sensor out of your old motor and put it in the new one. you may have to swap the coolant cross over tube depending on how many temp sensors you have. if you have only one in your forester then you will be fine and don't have to swap it.

 

then maybe the oil pressure sensor, but i got to think they would be the same. but you could swap it just to be on the safe side.

 

aparently in later year phase 2 ej25s they did change the cam triggers and wont work. i got my motor from a 99 forester and didn't have to change anything. i just swapped the cam and crank sensors from my 2.2 and it worked great.

 

it's doable and pretty easy.

 

check out my write up on my swap

 

http://www.ultimatesubaru.org/forum/showthread.php?t=83839