Any Issue Rebuilding With an '04 STi Crank & Rods in an '04 WRX?

[LaszloT]

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.

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

[STeveD]

Look for 4032 alloy pistons specific to the 2.2L 79mm stroker kit. Talk to us again right before you choose someone to assemble it.

[LaszloT]

Thanks STeveD,

I'm planning a proactive rebuild for my EJ205, likely in May.
Caveman is willing to help me remove and replace it, and we'll do that in Orillia where he is and where I have access to a garage.
I'd like to order parts from BuiltEJ, and already have an estimate from them.
Would prefer to deliver the shortblock with heads attached to a machine shop with the new parts (pistons, crank, rods, bearings, etc.) and get it back assembled that way.
They can do the boring, honing and any surfacing and valve work there.

Not sure what machine shops provide this type service and are familiar with EJ engines, but Touge Tuning uses Gord Bush Performance in Etobicoke.

Think Can-Jam can do it too, but they seem always to be heavily booked.

[STeveD]

Strokers are a bit special. Stuart (CanJam) and Gord are good choices. Gord will likely be able to prioritize it sooner, you are correct, but it doesn't hurt to go in and ask at CanJam. Trevor gets faster priority than I do, for example...

[LaszloT]

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.

https://www.facebook.com/22512505751...type=1&theater

[LaszloT]

I like this list of rebuild options I found on NASIOC:

"Here are some options. I'm listing various options and not necessarily recommending any one path over another, as it depends on what kind of powerband you prefer. Some want a revvy engine, some want more off-boost / low end.

- gaskets. Generally this is a dealer item sold as a kit for about $300-400ish. Otherwise you're piecing together a lot of gaskets. There are a few gaskets that you really want to be OEM. Head gasket really wants to be OEM, Alternatives to OEM HG have been hit or miss. Exhaust gaskets really want to be the OEM style of MLS plus metal fire ring. Other styles will eventually blow out.


- crank: re-use stock crank if it looks good. New OEM crank is in the $350 range, cheap enough that if anything looks out of the ordinary, it's generally best to just replace it so you don't have to play games with buying multiple sets of bearings to get clearances right on top of the machinist costs for polishing. If you so choose, you can move to an OEM 2.5L crank (same dealer price as the 2.0L crank) for a longer stroke that increases displacement to 2.12 liters, this gives a little more off boost torque, but will require immediate re-tuning because the timing curve on the 79mm stroke is very different than with the 75mm stroke.

- If staying 2.0L you can use stock pistons. Forged will hold up better to abuse, but you will get more oil consumption, especially after putting miles on. 2.0L pistons don't have the same ringland cracking issues that the 2.5L pistons have, but 100+ HP per cylinder is definitely in the yellow/red zone of any cast piston. If choosing the 79mm stroke crank, you need the appropriate pistons to go with them. There's a few brands who have standard pistons for this application. At the very least Mahle has 4032 and 2618 alloy in this application and Manley has a 2618 alloy piston for this. I'm sure there are others.

- OEM bearings are fine, but aftermarket is usually cheaper. ACL has been spotty on consistent clearances. King entered the market recently due to people wanting another source with ACLs having issue. Talk to wherever you buy your parts for what they recommend.

- Any head parts... If you have miles, you likely need valve guides, seals and springs (you can use 2.5L valve springs if you want, or aftermarket springs, people seem to like GSC beehives for OEM valves, as seat pressure is not as high as straight springs.)

- early 03s are shim over bucket valve lash adjustment and late 03s are shimless bucket valve lash adjustment. If you aren't shimless you can consider converting. Buckets are pricey, and this costs ~$400 for all the OEM buckets needed to convert, but you save about a pound of valvetrain weight and have a more reliable head at high RPM operation shimless heads can rev as high as the springs will allow, so this can raise your redline (which is kinda useless on stock cams, but that brings up the next point...)

- If getting into the heads, you can consider finding used 2.5L camshafts. These are a cheap upgrade (usually $100-150 used) and will hold power better at high RPM. Stock 2.0L cams are hurting power somewhere around 6k and up. You can extend redline to 8000 RPM with aftermarket valve springs + 2.5L cams + shimless buckets. The oiling holes for AVCS need TIG welded shut if you know someone who can do that for you. You can also tap the holes and screw in setscrews, but this tends to develop a slow leak. Some tap the holes and put in setscrews, then weld those in. There is a big thread on this in the big sticky list at the top of the forum.

- OEM 2.5L rods are one good option for rods. 2.0L rods are twigs by comparison and there have been a few cases of rod failures at sub 400 WHP levels. The appropriate aftermarket alternative are the chinese metal H-beams (Manley, Eagle, and lots of other "brands" using virtually the same rod are all in the $350ish range.) These cheap H-beams are slightly lighter than the OEM 2.5L rod, but slightly more expensive. Both are adequate for <400 HP. 2.0L rods have failed well under 400 HP, but there aren't a whole lot of failures. But it's worthwhile to upgrade here.

- Pre-built subaru shortblock...
There is also the option of buying a pre-built brand new 2.5L shortblock from Subaru. You get your heads machined to enlarge the chambers (either by a local machinist or ship them to equilibrium performance and have them enlarged by CNC to match the factory 2.5L chambers) and you have significantly more displacement and a rebuild for very little actual work compared with a complete rebuild. Cost is actually not much more than doing everything yourself when you consider the parts + machining + balancing, and that stock block should support your power goals. Block is around $2k from Subaru, so there's some wiggle room in your budget for gaskets and working on the heads. 2.5L cams are also recommended with this route. You can buy these from any Subaru dealer or from one of the various Subaru online shops (but shipping hurts almost as much as the non-discounted dealer price).


Not sure what I'm forgetting. Obviously timing belt stuff should be replaced. Water pump is at your discretion.


Some online Subaru places online with extensive engine building experience that you can ask them questions...
Realstreet
flat irons tuning
IAG
I'm sure I'm missing a few who contribute here and have extensive Subaru knowledge.

There are also lots of "generic discount" places online that you may save $20 at, but won't be able to answer your questions and don't really contribute here."

http://forums.nasioc.com/forums/show....php?t=2404794

[LaszloT]

In a stroke of good fortune I was given a spare EJ205 shortblock in good condition which had 140,000 km on it. It's condition was verified by a reputable builder, so it seems like a good place to start.

With a spare EJ205 shortblock I can get started early on my rebuild. If I can find rebuilt heads where I'll get credit for the old cores, I might be able to have a longblock built before I pull the old engine out, making an engine swap potentially a weekend operation.

This would be great!

[JoeT]

That's fantastic, I know where that came from.. It's in good shape, and the granny that drove that car thinks that accelerating at 1/4 throttle to the speed limit is a thrill!!... Notice, you can still see the cross hatching on the cylinders.

[STeveD]

Well.... there's always another option.


Send the EJ205 to Outfrontmotorsports.com and have them close the deck and build it into a 2.12L stroker short block, then re-use your 2.0L heads and cams. CanJam can do the same service here as well... but again... timeline. But if it's being built off-line... maybe not so critical.

Sure, there's no replacement for displacement... but the 2.5L semi-closed deck block is prone to HG failure due to the thin cylinder walls with no HG stabilization from a closed deck. For ultimate reliability, you should close that up anyway.

Add 13mm headstuds for more cylinder pressure resistance. EJ205 closed deck, 13mm headstuds, <300whp... should be the longest lasting Subaru headgasket around.

[LaszloT]

Looks like this build work is going to be coordinated by Touge Tuning, likely in the fall.

1. Rebuild the spare EJ205 shortblock in advance
- Gates OEM Water Pump & Timing Belt Kit - 2004-2005 Subaru WRX
- 4032 alloy forged pistons
- OEM or equivalent bearings
- OEM head gasket
- 10 mm OEM oil pump
- ARP head studs

2. When shortblock ready, yank the engine and deliver the heads.

3. Cylinder head service (1 – 2 day turnaround)
- Basic head service we have done is cleaning, pressure testing and decking the heads, plus re-shim valves/cams, valve seats redone, parts replaced as required

4. Pick up longblock when heads ready and assembled
- Likely in a GTI with the rear seats folded forward to make a deck

5. Reassemble the engine on an engine stand in Orillia and then re-install in the WRX.



Total down time - less than a week!

[LaszloT]

Happy Easter! I got my remanufactured EJ205 cylinder heads from BuiltEJ this weekend.







They are ready to be installed on a shortblock!

[dubya_rx]

Couldn't find anyone local? Just wondering.

[STeveD]

FYI: BuiltEJ was formerly named SloBoy racing. They were a sponsor of SPDA's Ottawa division through their crewing for Andrew Comrie Picard and offered club members some really good prices. Not local, but a history of club support.

When I was looking at doing a 2.2L Closed deck block for the STi, BuiltEJ had a reasonably priced option for me. Last I checked, there were no local vendors of Wossner pistons, but Mike also ships those up here.

[Cavemanrjc]

So when are we going to make smoke with it? I have prior engagements this weekend but after that nothing going on.

[LaszloT]

Local would be better Walter, but for a similar price to rebuild cyl. heads I get a 2nd set with cams that will let us rebuild a complete long block BEFORE we take the WRX out of service for the engine swap. That has some charm.

I need to start printing out the rebuild pages in the Subaru service manual as a reference.

[Cavemanrjc]

Why? Joe's still runs and I did not have a manual lol

Plus had to deal with an incorrectly installed oil pump seal.

Yours is gravy. Just a stock Eng swap lol