Subaru Impreza GC8 & RS Forum & Community banner

21 - 40 of 54 Posts

·
Registered
2001 D2 A8L
Joined
·
928 Posts
This is exactly the reason I was asking. I tend to keep vehicles until they're completely dead, which means that although the new EJ203 I received has under 40,000 miles, I may eventually need to do head gaskets on it. Knowing now that the 2002-2005 WRX EJ205 head gaskets are compatible with the EJ203 is valuable information.
No, it's not. Grnwagon confused you by saying it is the same but it has not been confirmed to be true. That is why he said you would potentially order custom thickness gaskets from Cometic. Doesn't sound like valuable info to me as all Subaru 2L motors have the exact same bore but may have different thickness gaskets. Do not use an EJ205 head gasket unless you confirm it is the exact same thickness
 

·
Registered
2005 Subaru Impreza 2.5RS Seda
Joined
·
9 Posts
Discussion Starter #22
@ chandlerbingco i inboxed you. Check your pcv valve as the jdm and usdm are in different locations. The usdm one is built into the block under the intake manifold and the jdm one is near the top of the intake manifold and is plastic. I believe it is in my pictures. If not i can send you the location. That is a common thing that people forget to put in as they think its in the same location as the usdm one. Also the rattle could b anything mine rattles but its the heat shield on the exhaust. I have since removed it and rattle goes away. You have a 30 day warranty jdm racing motors. If theres an issue with the motor they will send you the replacement parts considering most parts are fairly new or been replaced before you get the engine it shoud not be a timing belt tensioner issue or something of that matter check i over thoroughly if it is indeed the engine internals jdm racing motors will send you a replacement for free providing you inform them within 30 days and that the proper policy is followed. Inbox me anytime with any questions or problems and ill be more than happy to help
 

·
Registered
Joined
·
6 Posts
Got it - thanks. The JDM EJ203 seems to come with MLS head gaskets instead of the graphite composite ones on the USDM. Seems like the general sentiment is that the JDM gaskets are more durable and less prone to failure, so hopefully I never to need to remove the heads.
 

·
Registered
Joined
·
6 Posts
A few additional notes from my own completed EJ253 --> EJ203 swap for the record:

1. I second the double checking of the PCV valve swap - they EJ253 is built into the block and the EJ203 is a separate component that slides onto the intake nipple. I forgot to swap these the first time and it resulted in high idle (1500 - 2000 rpm) and smoking like crazy. After swapping the PCV over, the high idle immediately stopped and settled down to ~700 rpm. The smoking gradually went away, although it took probably an hour of idling to clear out the excess oil in the intake.

2. If you have an A/T (4EAT or other), make sure to remove the throttle body from the intake so you can access the flex plate cover, remove the black plastic cover, and manually rotate the engine until each of the four bolts connecting the flex plate to the torque converter are visible. Remove all four prior to unbolting the engine from the transmission bell housing. I haven't done an A/T before and assumed it was similar to M/T removal. It isn't - A/T is much simpler so long as the flex plate is unbolted first! Also, the flex plate from the EJ253 fits the EJ203 just fine.

3. I did not swap the cam gears from the USDM to the JDM. Several sellers say you need to do this because the position sensors won't work. In my experience, this isn't true. My EJ203 worked just fine with the original cam gears left on.

4. I had to remove the timing belt to swap over the driver-side gear cover housing from USDM to JDM because the JDM engine's was broken off. The timing components between both engines are indeed essentially identical as other posters on this thread have suggested. However, the hydraulic timing belt tensioner is easy to damage. There are some good methods on Youtube that indicate how to correctly remove the timing belt and I suggest watching those. When the whole assembly is reinstalled, pay particular attention to the tensioner and ensure it is working properly. You can tell by manually rotating the engine and watching to make sure the belt is always tensioned and does not slip on the cam gears. If it does, the tensioner needs to be replaced because a slipping timing belt will cause a major headache you don't need.

5. The knock sensor, which is located on the driver side, just underneath the throttle body has a different connector and needs to be swapped.

6. Although the USDM and JDM engine mounts look a little different, the bolt locations and mounting position on the engine and the cross member are identical. They are interchangeable. I jacked the transmission up to make more room for the engine mount bolts to clear the cross member when dropping the JDM engine in, but wasted about three hours trying to line everything up right. In the end, I loosened the engine mount bolts as far as I could while still leaving the mounts attached to the engine and used the slack to position the bolts into the slots in the cross member. This made the re-installation process much easier. Once the bolts are in the slots, tighten the mounts to the engine block before setting the engine down the rest of the way.

7. The coolant temperature sensor has a different connector so the USDM and JDM need to be swapped, but I found the location on both to be the same - in the cast coolant tube that runs across the top of the block. Both sensor locations in mine were facing the front of the engine.

8. The only issue I've had from the ECU so far is a blinking "CRUISE" indicator. Other threads suggest this is due to disconnecting the battery and may require an ECU reset, but I haven't done this. I'll report back once it's on the road if there are other problems.

9. This swap to an EJ203 only works if you do NOT have the AVCS (Adjustable Valve Control System) on your EJ253. You need to check because it looks like this started to become available around 2004/2005. In my case, the 2005 Outbacks only had them on turbo models so I was good. If there is a question, JDM Racing Motors has techs that will help you determine whether the swap will work or not.

Otherwise, the OP's post is informative and correct and swapping an EJ253 to EJ203 is a relatively simple and straightforward process. I also had good luck with JDM Racing Motors - total cost of the EJ203 with freight was $1150. They shipped UPS Freight and the delivery had a hydraulic pallet jack and rolled the new engine up the driveway and into the garage.

Also, the OP's post was on a 2005 Impreza 2.5RS with M/T. Mine was on a 2005 Outback 2.5i (non-turbo) with A/T. Please feel free to PM me as well and I am happy to help try to solve problems other have attempting this swap in the future.

This has been a very valuable thread, so thanks to all for the input.
 

·
Registered
2005 Subaru Impreza 2.5RS Seda
Joined
·
9 Posts
Discussion Starter #25
chandlerbingco, just a heads up for your cruise light, could be due to an engine code stored but not current, example, if the check engine light went on then off, its a stored code, as for AVCS same on mine, my rs did not have it therefore it worked, my knock sensor and all other sensors besides the 1 which is the coolant temp sensor, they are all the same connectors, the only reason for you is because you have an outback and not a 2.5rs. the cam gears and timing belt and etc for the timing belt, i didnt swap any of it, kept the jdm stuff on as stated in my thread, the 2.5rs engine mounts and the jdm203 engine mounts are the same however, for the jdm engine, they torch them off, which is why i swapped mine. it was a learning experience but jdm racing motors and my connections in alberta who have done this swap before, have helped me. to clear the smoke faster you could have went for a nice ride, which is what i did, to clear it quickly. i appreciate that people actually like this thread and are able to use it as a good tool to swap their subarus. i love this engine as much if not more than the ej253 and with a tune in it, will be even better.
 

·
Registered
1996 imp jdm ej20 NA dohc swap
Joined
·
400 Posts
Post #9
First off, the usdm ej205 from the 02-05 wrx shares the same head gasket as the jdm ej203 engine, same bore diameter (92mm) and coolant port spacing, so there is a few parts that can be found. Cometic would be the way to go for these head gaskets if it is needed in the future so a person can get the correct thickness.

For the valve covers, the ej251/253 stuff will work just fine along with the intake gaskets and such.
Post # 15
For the head gaskets you will. The only difference is the thickness unless they spec the same. That is why I said cometic so a person can get the correct thickness head gasket if the ej205 turbo ones are not the correct thickness which is most likely the case.

The head gasket of the ej251/253 is 99.5 mm in diameter and the bore diameter of the ej203 is 92mm, BIG difference.
Reread my two posts from page 1/2 which is put in black at the top. I have seen pictures of an ej202/203 head and it shares the same coolant ports as the ej251/253 which shares the same coolant port design as the ej25D na heads from the 97-98 legacy ej25D na engine and the 02-05 wrx ej205 heads.

How much do you have to bet on this? Any takers?

So for anyone else reading this, you get usdm ej205 turbo style head gaskets from cometic (if you are in the states) but in the correct thickness, that is that. If you find an importer who can get you a set of hg's then great for the ej202/203. This is "if" you need to do a head gasket job or prefer to change them out before putting the ej202/203 into the car.
 

·
Registered
'97 Emerald Green GF4 5spd
Joined
·
271 Posts
Wanting to bump this thread ip. Anyone did a ej201 swap coming from a ej251? I would only assume the ej201 have majority compatible parts with the ej251?
 

·
Registered
01 Impreza 2.5RS
Joined
·
174 Posts
Wanting to bump this thread ip. Anyone did a ej201 swap coming from a ej251? I would only assume the ej201 have majority compatible parts with the ej251?
Yes those swaps (ej251-> ej201) are very similar to the ej253 ->ej203 swaps in that you dont have to replace cam gears or crank gears. Just make sure they dont give you a ej202 instead of a ej201.
 

·
Registered
Joined
·
2 Posts
Slightly different swap

I have an interesting situation, and would like to see if anyone here can help me out.

I did an engine swap similar to the OP, though it was from an EJ251 to an EJ203. This happened because the JDM import company sent me the wrong engine, but said that it could work with a little more retrofitting (mainly plugging the hole in the head for the EGR valve tube).

So far I have swapped the flex plate, intake manifold, wiring harness, coolant temp sensor, knock sensor, and AC compressor. I also had to do some rigging to get the PCV to work, the old engine had a threaded nipple coming from the block while the new engine just had a straight hose connection.

The problem is that the car will not start. I've been over it many times to ensure everything is plugged in, and everything matches up. The JD import company I purchased this from have been very helpful (other than sending me the 203 as opposed to the 201), and they say that the crank and cam sprockets absolutely have to be swapped over as well.

Since I see many folks on this forum saying they do not need to be swapped when the last number is the same (EJ251 to EJ201, EJ253 to EJ203 etc.) I was hoping to get some input on my situation, where it is from the EJ251 to the EJ203.

Thank you for your time.

EDIT: The rigged PCV may be part of the problem now that I think of it, the threaded nipple that was installed on the old engine block may be the actual valve as opposed to the nipple on the throttle body, I'll have to check when I get home. Maybe I can swap the PCV from the new intake manifold?
 

·
Registered
Joined
·
163 Posts
EJ251 uses the 6/7 trigger with a JECS ECU. The EJ203 uses a 36-2-2 trigger with a Denso ECU.

So indeed, you do need to swap the crank gear and drivers cam pulley.. After that it will get crank signals that it knows what to do with... If the importer had done their job and shipped the right engine to you, it would have worked the way it was but 201's are harder to find than 202/203's and otherwise still direct swaps
 

·
Registered
Joined
·
49 Posts
Hey Kenny,

did switching the gears/pulleys work for ya? Currently debating getting a 203 or a used 251 locally. Leaning more to buying a lower mileage jdm motor.
 

·
Registered
02 Bugeye STI & 03 Forester XS
Joined
·
4 Posts
So I am thinking of doing this swap myself on my 2003 Forester. What I don't quite understand is if you get the EJ201/203 ECU along with the engines? The tuning is different between them, but nobody talks about swapping out the ECU's.
 

·
Registered
2005 Subaru Impreza 2.5RS Seda
Joined
·
9 Posts
Discussion Starter #36
Its been stated above on page 4 thst you can simply swap some of the parts that you swap over. Matt167 posted it
 

·
Registered
Joined
·
1 Posts
Does the year of each motor make a difference in the compatibility of the EJ253 to EJ203 swap? Currently I have a 2009 Subaru Impreza which I believe has the 253 motor. All over the place I have been able to readily find the JDM 203 motors with significantly less miles for hundreds less than a EJ253 that was pulled from something more current. Problem (or maybe not?) is that most of the EJ203s ive seen are from 2004-2005ish. Will this still be compatible?

Thanks in advance!!!
 

·
Registered
01 Impreza 2.5RS
Joined
·
174 Posts
Does the year of each motor make a difference in the compatibility of the EJ253 to EJ203 swap? Currently I have a 2009 Subaru Impreza which I believe has the 253 motor. All over the place I have been able to readily find the JDM 203 motors with significantly less miles for hundreds less than a EJ253 that was pulled from something more current. Problem (or maybe not?) is that most of the EJ203s ive seen are from 2004-2005ish. Will this still be compatible?



Thanks in advance!!!


No these won't be compatible. The newer 06+ engines have avls heads which will throw a check engine light if it's not plugged in.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
49 Posts
Howdy all,

Wanted to chime in on this as I've recently just did the swap this past weekend. MY00 RS with the ej251 in it, swapped it with a JDM EJ203 and it works beautifully. Follow the instructions on the post and you wont have any hiccups. Literally all you have to do is swap over sensors(UD pulley sensor & drivers cam sensor), drivers side cam, under drive pulley gear and under drive pulley and intake manifold.

I plan on doing more testing and will come back with more info and further review of the engine. So far it's great, less power obviously but not too bad. can still get up and go. Lost the low end grunt of the torque but again, least the car wont fail. The power is actually a lot more liner and feels nice/smoother.

Here is the link of it running for proof.

JDM EJ203 in a 2000 Impreza 2.5rs - YouTube
 

·
Registered
Joined
·
49 Posts
Just wanted to give an update on the car. Still running strong and no problems at all! I have roughly driven 500 miles on it. I did happen to run across P0130 from my Bosch front o2 sensor that's not even 2 years old but I think that's due to my middle exhaust flange (donut looking gasket) is practically gone. Will be switching it out and or deleting/welding in a piece of exhaust to get away with needing that stupid gasket.

I'll hopefully be starting a member journal as I've been wanting too for awhile but work on the car is very slow. Hope this helps the future swappers out there.
 
21 - 40 of 54 Posts
Top