JDM EJ253 conversion for 2000 Impreza RS

[corona56]

I have a 2000 Impreza RS auto with a ton of miles (225k). It runs really well but is experiencing intermittent overheating issues that I believe are the result of a head gasket issue. Since the motor has a ton of miles, I have started looking at swapping the engine vs. just getting it repaired. I can find a JDM EJ253 for the car with instructions to keep my intake and exhaust as part of the conversion. This makes sense, since the ECU will be different for the JDM engine. So my questions are the following ...
1) will the intake and exhaust have the same layout so I can use my existing intake manifold, wiring and exhaust manifold?
2) will I by missing the EGR system? I have read that EGR port is may not exist on the JDM engines and if not, will this result in ECU codes?
3) any other issues I should worry about putting in the JDM EJ253 in this car? Transmission hookup, etc.

Thanks. I know there are a lot of thread on this topic, but I searched and could not find specific details on using an EJ253 in the 2000 RS.

 

[El_Freddo]

Welcome to the forum Corona!

I can't answer all your questions - I presume your RS impreza has an EJ20 of some sort in it? Or is it already rocking an EJ25?

1) If the engine is of the same era, it *should* have the same intake manifold bolting pattern. I'm not 100% sure though - some one will know.
Exhaust, if you've got a dual port exhaust you're good to go. If not get one made up or get the factory manifold with the engine if possible.

2) I'm pretty sure all Subaru engines have an EGR system, I doubt it would be any different for the JDM EJ253 - they probably have stricter emissions laws than anywhere in the states!

3) Tranmission/engine mounts etc, all lego. Swap the flex plate onto the EJ253, bolt the torque converter to that and happy days!

On another note, 225k km isn't a great deal of k's for these engines. My sister's Gen3 RX Liberty that runs the EJ253 is still pulling like a Trojan with 350k km on it. We did the HGs at about 330k km due to an oil leak in the passenger side head gasket (AUDM, so driver's side for you guys that haven't got it right )

It's a very nice car to drive (manual). A set of UELs make it sound awesome too - a car you want to drive all the time

Cheers

Bennie

 

[corona56]

The car has an EJ251 engine. It does have a Y front pipe with two inlets for the exhaust. I believe I have read that JDM engines do NOT typically have EGR and to NOT have ODBII; so my guess is that emissions standards are less in Japan. I know that is the case for Europe although that seems to be changing as there are more cars on the road and city smog is becoming a problem.

 

[El_Freddo]

From reading bits of this thread (last post seems good) https://www.rs25.com/forums/f5/t171730-ej251-vs-ej253.html and some other reading on NASIOC it sounds like the intake etc on the EJ251 and EJ253 are interchangeable.

This thread is even more promising:
https://www.rs25.com/forums/f128/t202604-can-i-swap-ej251-ej253.html

You may have to swap cam and crank timing gear, which will mean removing the cam belt. It's a great time to do your front oil seals and a new cam kit. I'd throw a new water pump on too.

Also be sure to reseal the oil separator plate and replace the rear main seal while everything is easily accessible!

Looks like the last hurdle for this swap is working out the EGR system.

Cheers

Bennie

 

[corona56]

From what I have read, the 2000 Impreza RS 2.5 does not have an EGR system. I looked on the car and that seems to confirm this.

 

[corona56]

On the topic of swapping timing gears. My existing engine has a brand new timing belt kit complete with bearings, water pump, pulley. So I assume I can just move that to the new engine and I am good to go with regard to the cam and crank gear switch, right?

 

[El_Freddo]

Correct.

Just keep the cam belt clean and note the direction it rotates if the markers have worn off already.

Cheers

Bennie