EJ20G Swap - What years are compatible?

Heads, valves, pistons, rods, crankshaft, etc...

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monkeyposeur
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EJ20G Swap - What years are compatible?

Post by monkeyposeur »

I have been thinking about getting a complete JDM EJ20G engine for my 93 SS. I know the 93-94 EJ20G should swap right in, but what about later EJ20Gs? I see 97-98 JDM EJ20Gs for example.

I think my HGs might be slowly failing again on my SS and if I have to pull the engine again I was thinking about just swapping the 20G in but use my 22T block that is in the car.

Also, if anyone knows where to find the JDM EJ20G VTD TCU I'd be psyched. My wife drives the SS and wants to keep it forever but she doesn't want me to swap in a 5MT. If I could find the JDM TCU I could get an engine/4eat package on ebay for failry cheap. Her 4EAT has about 197k on it so I'd like to have a backup.

Edit: I have a RobTune ECU and 4to2 converter. I haven't installed it yet.
93 SS - SOLD
03 WRX 22T/205 20GXT 350 whp
06 OBXT
95 BK - Sold to my neighbor.
mike-tracy
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Re: EJ20G Swap - What years are compatible?

Post by mike-tracy »

The later 'ej20g' engines with the coil pack on the manifold aren't electronically compatible like the older ones, neither with the ej22t ecu or with the older 4-plug ej20g ecu.

Can you use one? Sure, with a wiring merge, or other modifications (replace manifold with an older coil on plug ej20g one and reuse your ej22t intake manifold harness, losing the newer manifold's cool under manifold turbo path) etc.

The closest thing to a direct swap would be real ej20g with coil on plug.
1992 Legacy SS 5mt, build in progress
Josh Colombo wrote: Mon Jan 14, 2002 10:23 am Wait....I'm confused now.
monkeyposeur
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Re: EJ20G Swap - What years are compatible?

Post by monkeyposeur »

Ok, that's what I suspected. Thanks Mike!

I'm suspecting early HG failure because although there are no visible coolant leaks the car was down over a gallon of coolant yesterday. My wife called and said the car had overheated. I filled it back up and it is running just fine, but the coolant has to go somewhere so I suspect an internal leak. I regularly check the plastic overflow reservoir and have topped it off a little bit every now and then when it got low.

I have installed an aluminum WRX coolant reservoir so I was able to fill the system with my trusty Lisle funnel. The coolant isn't milky, and the plastic overflow tank shows no sign of bubbling. However, when I was filling up the system upon revving the engine as the rpms decrease I would see some small bubbles in the Lisle funnel. This makes me suspect as the engine is decelerating it is pulling more of a vacuum which may draw in a small amount of coolant. The deceleration of the engine is accompanied by a very slight amount of whitish water vapor out of the tailpipe. But I can't smell any coolant when this occurs.

The boost gauge is showing the usual vacuum on idle, and I can reach and hold factory 8.7 psi under boost.

A few years ago, the upper radiator hose split open and all the coolant was lost. My wife thought that she should just continue on driving home for another 15 minutes. :smt011

After replacing the hose and filling up the system the car appeared to suffer no damage so I counted my blessings and it has been running fine since.

Perhaps she slightly warped the heads and helped the HGs fail??? She has about 30k on the HGs at this point.

I plan on doing a leakdown and compression test to see if I can gather any additional information when I get some time.

She does have a slightly weak idle which could be a result of a lot of things, but if indeed the HGs have a small leak this could be the culprit.
93 SS - SOLD
03 WRX 22T/205 20GXT 350 whp
06 OBXT
95 BK - Sold to my neighbor.
mike-tracy
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Re: EJ20G Swap - What years are compatible?

Post by mike-tracy »

Possible to be HG, but it could be the weep hole on the water pump is seeping, indicating the water pump bearing is going out. Happened to me, I had a wierd coolant loss for ages. New pump fixed the coolant loss.

I don't want to dissuade you from getting a 20g, they really are pretty neat engines. :)
1992 Legacy SS 5mt, build in progress
Josh Colombo wrote: Mon Jan 14, 2002 10:23 am Wait....I'm confused now.
monkeyposeur
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Joined: Mon Feb 20, 2012 5:44 pm
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Re: EJ20G Swap - What years are compatible?

Post by monkeyposeur »

Would there be any visible coolant loss from that?

When I replaced the HGs the first time the timing kit came with an NA water pump even though I had ordered the 22T kit (from Gates, not Subaru), so I reused the pump.

Edit: do you think a WRX water pump will work as an equivalent pump?
93 SS - SOLD
03 WRX 22T/205 20GXT 350 whp
06 OBXT
95 BK - Sold to my neighbor.
mike-tracy
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Re: EJ20G Swap - What years are compatible?

Post by mike-tracy »

My leak was so slight I didn't see a leak till it got really bad. Still had a noticeable coolant loss the whole time. I was maybe adding a cupful of coolant a week.

The WRX water pump is a direct fit for the 22t with the oil cooler - 1991 only. You could cap off that port on the water port, or add a cooler without pulling the engine. I'm kinda leery about capping a port - what if it failed down the road, etc.
1992 Legacy SS 5mt, build in progress
Josh Colombo wrote: Mon Jan 14, 2002 10:23 am Wait....I'm confused now.
monkeyposeur
First Gear
Posts: 227
Joined: Mon Feb 20, 2012 5:44 pm
Location: Salt Lake City, UT

Re: EJ20G Swap - What years are compatible?

Post by monkeyposeur »

Yeah, I don't like capping coolant ports. If I did I would tap the port and JB Weld a bolt in there.

I have a 91 oil cooler/warmer in my parts bin but I don't feel like adding any complexity to the SS. I also have a used 22T pump in there but I haven't dug it out to compare to a WRX pump so thanks for the info. I'll see if any OEM 22T pumps are left from SOA.

Another question which I'm sure has been answered before. If I did a 20G swap and run the RobTune w/4to2 conversion, do I need special plug wires or do I just use what I am already running on the 22T stock setup I have now?

I'm not ready to let the SS go yet. I have two new fenders, EDM headlights, a RobTune ecu, new TD04, 06 FXT tmic, and new sidefeeds sitting in the basement lol.
93 SS - SOLD
03 WRX 22T/205 20GXT 350 whp
06 OBXT
95 BK - Sold to my neighbor.
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