Auto vs Manual EJ253

Red XS

Red XS

Forum Member
Joined
Dec 6, 2013
Messages
908
Location
Perth, West Aus
Car Year
2006
Car Model
SG Forester XS
Transmission
1.447 Low SG Manual
The EJ253 in my 2005 (MY06) SG manual Forester is due for some maintenance. For negligible extra cost I can get a 2010 EJ253 out of a SH automatic Forester with 190,000Km less. My current engine isn't bad, so I'll only consider the swap if it's straight forward.

So far I believe that the SH motor will fit straight in and the manual transmission will bolt straight up.

I'm unsure about the differences in the electronics between manual and auto motors. Will my manual ECU and all of the sensors plug straight into the auto motor and run it with out issue or are there some fundamental differences between the two motors?
 
At the same cost (approximately), I would do the required maintenance on your existing engine.

Short of doing the same maintenance on the SH engine (extra cost), you cannot be assured that you are exchanging one set of problems for another.

Doing this also avoids nasty surprises ... Changing trannies is not as straightforward as one might think, judging from my one experience some 40+ years ago. And that was in the days when an ECU wasn't even on the horizon.

SWMBO's SH has a slightly different engine from that in Roo2, even though both are EJ253 engines.
 
I would still put on new timing belt, water pump, head gaskets and seals onto the new engine if I went that route. I am keeping my manual gearbox, just wasn't sure how an engine that had been paired with an auto would match.

Compression is just a bit low and uneven on the old engine. I was going to change valve seals and inspect cylinders and valves when the heads are off, any machine work can quickly offset the cost off swapping engines. While I don't know the history on the other motor, I do know mine has not had an easy life, however does still run really nice.

Differences between the two engine models are a bit off putting...
 
It might go without a single hitch, Red. I don't know.

What I do know is that these things can have unforeseen problems/consequences sometimes.

Even swapping a later model SG donk in might cause some problems with the ECU. Again, I'm speculating. I just don't know.

Maybe someone will come along who knows what is involved if we keep chatting about it!
 
I know they can turn into a headache. My mate upgraded his Ford with a Tickford motor. Took him a very long time to get it running and changed basically everything on it. For example he wanted an auto but ended up with a manual. End result is an awesome car, but what he went through is exactly what I want to avoid.

Default plan will be to keep my engine. But would be nice if someone has done something similar knows what to look for. Then I can knock a lot of kilometers off.
 
How about a low mileage EJ253 from your year SG? For example, mine has only done about 120K. I'm sure there are others like mine out there.
 
I could get the SH motor cheaper and I trust it more as I know the seller through mates. There is a SG one with 73,500Km on it that might be a better option.
 
auto/manual donks are unlikely to be different, but what you need to watch out for are differences in the sensors and engine wiring harness. The ECU's will be different (Auto/Manual same age, let alone different ages. Simple things like neutral sensor, clutch switch, idle speed control etc are all different manual to auto).

Just about all subaru EJ engine/trans combos bolt up with no mechanical hassles.

You want to ensure that the new engine plugs straight in. Same plugs on the engine harness, same sensors, same CR, etc. If injectors differ, they need to be swapped to your old ones.

If the sensors/wiring differ, then the next step is to use the new long block and your current heads/intake etc. Again, you need to be sure CR is ok. But if your old heads need work, this seems a bit silly.

You're safer swapping SG for SG unless you know what to look for.

EDIT: Wiki says post-2006 EJ253 have VVL on the intake. That's a big difference.
 
When I upgraded the EJ20 for the EJ22, it came out of a '96 4EAT Legacy. I kept eveything EJ20 (intake, injectors, ecu, exhaust, sensors, pulley...) except the EJ22 naked block.
 
swap engine is easier then gearbox from different years even more so. is it even worth it. auto car and manual have different brains. they think differently they handle AWD systems differently too.
 
scalman said:
....auto car and manual have different brains. they think differently they handle AWD systems differently too.
Click to expand...

Just keep the original brain and change the heart :biggrin:
 
Very useful Duncanm, Thanks!

Mine is definitely missing VVL
Jj5J2PNl.jpg


This is with VVL
25728d1351447935-variable-valve-lift-oil-pressure-switch-resistance-left-side-vvl-1-.jpg


So that reduces 'simple' engine swap options to a few months of production
 
Hmm. It is my understanding that all EJ253 donks have VVL. Major difference between the EJ251 in the SG series I and the EJ253 in the SG series II. I also thought that the oil pressure sensor was inside the camshaft covers, at the end of the camshaft. Also that it is a purely pressure sensing system that isn't electronically adjusted. I could be 100% wrong about all this of course ;).

My manual 2006 does not have the setup in your second image. It looks exactly like your first image.

Our sportshift auto 2010 SH with EJ253 has the setup in your second image. Maybe this is to do with the tranny type rather than the VVL?
 
That's good to know, sounds like all manual SG's are fairly safe then. I will have a look at the low km sg one for sale soon, hopefully everything looks the same.
 
[MENTION=12952]Red XS[/MENTION] I just dropped a EJ253 with 102xxxkm out of a 2006 XS Auto Forester into my 2007 X Manual with 272xxxkm and extremely leaky heads (Old man is a fully qualified mechanic of 35 years). You do need to swap the Timing Belt Guide over as the Auto's don't have one. Otherwise it was all the same, obviously you need to remove the flex plate off the rear of the crank and bolt your flywheel on as well.

As long as the engine is out of the same era you should be fine, a EJ53 out of a SH may work, but may also have different tech, the short block with your heads may work though...
 
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