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LW_Black4 02-20-2014 12:37 PM

Any Issue Rebuilding With an '04 STi Crank & Rods in an '04 WRX?
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Since I have access to these parts and the longer stroke would make it a EJ 2.2L build.

I'm hoping the modest additional displacement won't constrain cylinder head breathing or require fuel system upgrades at Stage 2 power levels. However, replacing the fuel pump and filter on a 10 year old engine at rebuild time is still a wise precaution.

[B]Do you know of any issue rebuilding my EJ205 with a '04 STi crank & rods?[/B]

psinuse 02-20-2014 12:46 PM

Well you'll need fuel injectors, fuel pump, tune, better plugs(use a step colder I believe) and a few other little misc. things(pistons will have to be aftermarket)

mosc 02-20-2014 03:18 PM

I dunno where you'd find pistons for those dimensions. Stock ones won't work. Keith, can you spec a piston like that?

LW_Black4 02-20-2014 04:54 PM

Sounds like custom pistons are required, with a 2mm higher wrist pin placement.

Manley Pistons Subaru Impreza WRX EJ205 79mm Stroker Crank 92.5mm 8.5:1
[url=]Manley Pistons Subaru Impreza WRX EJ205 79mm Stroker Crank 92 5mm 8 5 1 | eBay[/url]

psinuse 02-20-2014 05:42 PM

[quote=mosc;436193]I dunno where you'd find pistons for those dimensions. Stock ones won't work. Keith, can you spec a piston like that?[/quote]

Manley makes an OTS piston for the application as well as a couple others.

[quote=LW_Black4]I was hoping the OEM fitment had that kind of contingency capacity for 200 cc more of displacement?

Fuel system upgrades have to be considered as well then, but I do like STi Pink injectors.[/quote]
I highly, highly recommend a fuel upgrade, even the stock 2L on a Stg.2 can out flow the injectors. Pinks would work along with an upgraded fuel pump.

mosc 02-20-2014 05:44 PM

That's amazing that there is enough demand that they have off the shelf pistons for an EJ205 with that crank ready for purchase. I guess you're not the only crazy guy out there!

psinuse 02-20-2014 05:47 PM

This type of stroker motor has been out for a few years now and I believe even CP makes them. Biggest issue is the phantom knock tuners get with them. I know there is a plug that help resolve it, but for the life of me I can't think of it's name. MPS makes 2mm longer rods and sells them as a kit for stock 2L motor. Rods and pistons...seems kind of pointless unless you're wanting to make butt loads of power.

arcticscythe 02-20-2014 06:05 PM

Definitely grab a new pump and fresh injectors. You'll definitely need them for the new build spec but they are 10 years old, old/dirty injectors make it harder to tune and a less than stellar fuel pump wont be able to keep up. I did some work on a bored/sleeved 2.2l with the supporting mods everyones talking about back in high school but it always seemed to run funny. It drank oil like no-bodys business.

Your venturing into unknown territory, now is a good time to talk to your tuner and see if they have tuned anything like that. Its not quite as simple as adding 10% across the board to your stage 2 tune. at this point its a custom build and it deserves a custom tune.

LW_Black4 02-20-2014 07:27 PM

[quote=psinuse;436241] Rods and pistons...seems kind of pointless unless you're wanting to make butt loads of power.[/quote]

I like that you get STi crank and rod strength and durability for a WRX EJ205 with the swap. However [B]depending on the cost of the collateral upgrades required, it might not be the best value even if you can get the crank and rods cheap.[/B]

Pistons would be replaced in a rebuild anyway, so that's not an additional cost.

LW_Black4 02-21-2014 11:51 AM

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[B]I might be able to get the '04 STi injectors[/B] (520 cc) [B]and fuel pump[/B] (145 lph) [B]as well.[/B] Photos below. This would be great! :)

And if it all works out, I'd drill out the stakes in the TGV valves and remove the butterfly plates at rebuild time.

After that it'd get a custom tune and ultimately a turbo back exhaust.

mosc 02-21-2014 01:09 PM

If you have the stock STi injectors out, pay to get em modded. Will save you money in the long run. Mine made it to 812cc with just a nip and a flow test.

The Stock STi fuel pump is nothing special. Walboro's are cheap and good for more flow, I'd get one of those.

psinuse 02-21-2014 05:44 PM

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Those injectors won't work with your intake manifold...

You'll need these types of injectors.

LW_Black4 02-23-2014 10:23 AM

Ok gents, I have an update.

Car Club folks are saying that my EJ205 block is not a good one for a stroker application, because of it's open deck block. Additional side loading of the bores from the longer stroke crank shifts the top of the cylinders bores resulting in premature head gasket failure, even in modest power applications.

I want reliabilty for my rebuild investment, so I don't think I'm taking this approach anymore.

I can buy an OEM shortblock from BuiltEJ and get them to include refreshed cylinder heads in exchange for the head cores, and it looks like this is the least expensive way to get a new motor. I believe it will be a semi-closed deck block item too, which is better than the shortblock it replaces.

This is handy because the motor could be swapped in a single (maybe long) weekend then, which reduces downtime.



mosc 02-24-2014 11:25 AM

The only truly closed deck EJ motor that hit the US shores was the EJ22T from the 1991-1994 LGT. The top end of the motor is crap, SOHC, didn't even come with an intercooler but the block is excellent.

LW_Black4 02-24-2014 12:26 PM

I'm told that even a semi-closed block construction is not required for an OEM build at modest power levels like I want, unless I'm trying to make a stroker 2.2L out of it as well.

Pictures of a semi-closed block. I think it's the ribbing that supports the top of the cylinder in four places along it's circumference that makes it semi-closed.

Semi-closed JDM block

In the same post, wall thickness difference between JDM 2.0 and USDM 2.5

Here's the FB link: [URL=""][/URL]

Decided to go with an OEM build or rebuild now.

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