I am currently doing an EJ25 engine swap with a EJ20 JDM motor. I have a 2001 outback (170K) with a EJ25 SOHC engine that has a rod knock. Engine is out of car and on ground. Went down to LA and bought the JDM EJ20 engine yesterday, the vendor did a compression test for me and it was good.
I am now back at home and the intake is off and you can see into the valves and they are full of carbon, it looks pretty bad actually. I took off the valve covers and every thing looks nice and clean inside of it. When I look at my EJ25 heads they are pristine looking inside, very clean, not a sign of carbon build up and even the aluminum surfaces are clean. The 2001 EJ25 does not have EGR so the inside of the head looks great.
My question is should I swap heads and use the EJ25 heads on the JDM EJ25 short block? Is the EJ20 ok with that much carbon build up? The EJ20 heads have a multi layer gasket too, so no advantage to changing for that.
I am now back at home and the intake is off and you can see into the valves and they are full of carbon, it looks pretty bad actually. I took off the valve covers and every thing looks nice and clean inside of it. When I look at my EJ25 heads they are pristine looking inside, very clean, not a sign of carbon build up and even the aluminum surfaces are clean. The 2001 EJ25 does not have EGR so the inside of the head looks great.
My question is should I swap heads and use the EJ25 heads on the JDM EJ25 short block? Is the EJ20 ok with that much carbon build up? The EJ20 heads have a multi layer gasket too, so no advantage to changing for that.