rxleone Posted July 14, 2010 Share Posted July 14, 2010 So I'm looking at buying a N/A EJ22 Legacy, 1989 model. Typical EJ22, EFI, SOHC, etc. I was wondering if there is any way of putting DOHC heads onto this engine with minimal loom work? I'm not too confident with the EJ series, having only owned one EJ20D-powered 89' Legacy before, most of my time being spent on old-gen Scoobs. Hence, I'm pretty much a tool when it comes to EJ wiring/ECU work. So obviously, being a DOHC setup it would have a different Cam sensor setup, other sensors etc... So.. 1 - How difficult is it to change a loom in an early Legacy? Would be most likely taking heads from an early EJ20D N/A DOHC engine (think 1st generation Legacy) and transplanting them. Would the loom be theoretically plug-and-play into the EJ22-engined vehicle of the same year? Or would there be serious cutting-and-splicing involved? 2 - Would I also need to bring the intake from the EJ20D over to go on the heads? Or is it possible to run the EJ22 intake? 3 - What sort of power/economy gains would you most likely be looking at with this change? 10HP? 15? 20? I know the EJ22e is 135HP stock, while the EJ20D is 150HP... surely must be in the heads? Sorry if I'm all over the place, trying to brainstorm and I get like that Any help would be appreciated. Cheers guys. Link to comment Share on other sites More sharing options...
KiwiDan Posted July 14, 2010 Share Posted July 14, 2010 (edited) You wont have to change any wiring as the DOHC engines still only have one cam sensor, All you will have to check is that the cam sprocket that the sensor triggers off of has the same number of teeth. You will be able to retain the ej22 coil pack an just get some longer HT leads. You might have to change the inlet manifold but every thing on it will be the same so keep the EJ22 engine loom. You have to remove the dash and heater to change the loom in the car. Edited July 14, 2010 by KiwiDan Link to comment Share on other sites More sharing options...
rxleone Posted July 14, 2010 Author Share Posted July 14, 2010 You wont have to change any wiring as the DOHC engines still only have one cam sensor, All you will have to check is that the cam sprocket that the sensor triggers off of has the same number of teeth. You will be able to retain the ej22 coil pack an just get some longer HT leads. Everything else should be the same. Sweet, that's good to know! Now I just gotta buy the thing Link to comment Share on other sites More sharing options...
wtdash Posted July 14, 2010 Share Posted July 14, 2010 (edited) 99% sure your intake manifold has to match the heads so the bolt holes line up....and the head gasket should match the block. But, yeah, the wiring on the EJ22 and EJ20 should be the same.....although we didn't get the EJ20 over here, 'til the EJ20 Turbo in the '02 WRX. I'm not sure in your situtaion, but I know if we in the US put the 2.5 DOHC heads on the the EJ22 it LOWERS the compression ratio, which would produce less power......so do some research. GL, TD Edited July 14, 2010 by wtdash Link to comment Share on other sites More sharing options...
rxleone Posted July 19, 2010 Author Share Posted July 19, 2010 I'm not sure in your situtaion, but I know if we in the US put the 2.5 DOHC heads on the the EJ22 it LOWERS the compression ratio, which would produce less power......so do some research. Good point - I need to look into that. Anyone have any manuals in PDF online that have these specifications? Also - The body harness - do these differ in the 89' - 92' Legacies? EG. Can you swap the engine harness and engine from one engine (say an EJ20 or EJ22T) into a Legacy of the same shape and style, but different engine, can you just plug in the engine side of the loom, and the computer into the other end? Or does the body harness differ depending on the engine? Link to comment Share on other sites More sharing options...
ShawnW Posted July 19, 2010 Share Posted July 19, 2010 Seems like you are attacking that car like a bull in a China shop. Why are you changing all that just to put 4 cams in it? Link to comment Share on other sites More sharing options...
wtdash Posted July 19, 2010 Share Posted July 19, 2010 Good point - I need to look into that. Anyone have any manuals in PDF online that have these specifications? Also - The body harness - do these differ in the 89' - 92' Legacies? EG. Can you swap the engine harness and engine from one engine (say an EJ20 or EJ22T) into a Legacy of the same shape and style, but different engine, can you just plug in the engine side of the loom, and the computer into the other end? Or does the body harness differ depending on the engine? USDM Legacy's harness connectors are the same '89-91 and changed in '92. The wiring is slightly different between turbo and NA engines too. For instance, the Cam/Crank sensors' wiring is swapped (I always wondered Why? on that one!), but the ECU connectors are the same from '89-94. Td Link to comment Share on other sites More sharing options...
Fairtax4me Posted July 19, 2010 Share Posted July 19, 2010 Seems like you are attacking that car like a bull in a China shop. Why are you changing all that just to put 4 cams in it? Kinda wondering the same myself. I didn't think there was that much advantage to having dohc over sohc heads? Plus IIRC the dohc heads are all interference, so if the timing belt breaks you're SOL. (valves can hit valves) Link to comment Share on other sites More sharing options...
rxleone Posted July 19, 2010 Author Share Posted July 19, 2010 Seems like you are attacking that car like a bull in a China shop. Why are you changing all that just to put 4 cams in it? More efficient, more powerful. The strongest Subaru block we ever got in NZ with efficient heads. I'm not "attacking" anything, as I stated it is merely an idea, to see if it's possible. You know, trying new things? Kinda wondering the same myself. I didn't think there was that much advantage to having dohc over sohc heads? Plus IIRC the dohc heads are all interference, so if the timing belt breaks you're SOL. (valves can hit valves) As I have had this happen on my 89' EJ20 Legacy - I know the dangers of DOHC heads. However, as with anything on a car, if you keep the maintenance up, there's no problem. As you would have to buy a new belt for a DOHC set-up anyways, I don't really think it has any effect, at least not for 80,000km or so. Link to comment Share on other sites More sharing options...
Axiom614 Posted March 23, 2012 Share Posted March 23, 2012 I was under the impression that a lower compression was better for a turbo? also I was also told that you could use the 2.5 crank and it would be like placing a stroker kit into it. If i am or was told wrong please forgive me. This is why I joined the forum to inform myself properly.. Thanks.. Link to comment Share on other sites More sharing options...
Axiom614 Posted March 23, 2012 Share Posted March 23, 2012 any idea if the 2 pot calipers would fit on my 96 legaback 2.2?? Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 24, 2012 Share Posted March 24, 2012 I was under the impression that a lower compression was better for a turbo? also I was also told that you could use the 2.5 crank and it would be like placing a stroker kit into it. If i am or was told wrong please forgive me. This is why I joined the forum to inform myself properly.. Thanks.. If you're going for a turbo setup yes lower compression is what you want. But the ej20D was a higher compression N/A variant for the European markets. It never made it to the US. I'd be interested to know if the OP ever did this swap, and what the results were. Link to comment Share on other sites More sharing options...
wtdash Posted March 24, 2012 Share Posted March 24, 2012 (edited) any idea if the 2 pot calipers would fit on my 96 legaback 2.2?? Axiom, This is called 'hijacking' the thread-it's not related to Topic. Please Search and then start a new thread if needed. Also, this thread was 2 years old when you replied initially.....so you may not get a response from the OP (original poster). TD Edited March 24, 2012 by wtdash Link to comment Share on other sites More sharing options...
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