Best Value Light Rebuilt Engine Formulae

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Re: Best Value Light Rebuilt Engine Formulae

Postby bigBADbenny » Sun Jun 29, 2014 7:09 pm

Yep in order of $$$:
Rebuild with ARP studs,quality head gaskets and timing belt etc.
JDM 2.5L short
RSS built short (or similar)
CD block with custom internals...
And so on.
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Re: Best Value Light Rebuilt Engine Formulae

Postby cynner » Mon Jun 30, 2014 10:06 am

Cool thanks. I'd probably be at the lower level - rebuild with ARP studs,quality head gaskets and timing belt etc.

I'm assuming this is something that could wait for when I need a rebuild (eg: head gasket problems) - or is it something that would be worth doing when the timing belts need doing? (i'm at about 180,000kms at the moment)
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Re: Best Value Light Rebuilt Engine Formulae

Postby bigBADbenny » Mon Jun 30, 2014 11:16 am

Doing an HG and studs etc is around $2-3K with quality parts iirc.
Maybe double what a timing belt service will cost?

That's why I was looking into all the options, ideally one would spend a little more to get built, with quality, in some way...
Thus the STi short and RSS options are attractive.
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Re: Best Value Light Rebuilt Engine Formulae

Postby cynner » Tue Jul 01, 2014 10:48 am

Cool thanks. The RSS/STi short would be double again though wouldn't it? (did I read closer to $10k?)
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Re: Best Value Light Rebuilt Engine Formulae

Postby bigBADbenny » Tue Jul 01, 2014 11:45 am

An EJ257 short is $2500.
Not sure about the exact details, maybe call Kris to discuss.
Then add another $2-3K for install and required ancillaries (I guess).
The built engines are $3500 and up, you supply the short block.

So from research, its still a big jump to get over to a forged, decked build, even just forged pistons.
This is due to the very exacting tolerances required for a reliable build, and the required strategy, experience, skills and equipment needed for the job.

So if its for reliable street duty, and you're happy with not exceeding 250 atw or preferably less, and you have the required supporting mods, then the EJ257 short is the way to go.

I've decided pending further research to settle for well under 200atw and keep it all stock but supported for somewhat more.
Meaning the car will be smoother and more reliable than stock and have plenty of headroom and failsafes in place for tolerating the inevitable mechanical issues like hoses popping, bad fuel and so on. Having said that if my engine just expired somehow in the near future I have a better idea of where to put my $$$ ;)

Here Micks great post on the matter from Rexnet:
http://www.rexnet.com.au/forum/index.ph ... p__2549929
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Re: Best Value Light Rebuilt Engine Formulae

Postby Sean82 » Tue Jul 01, 2014 3:20 pm

Why the focus on EJ257 block over EJ255? Other than the dome/dish on the top of the piston, from 2009*-on the blocks are identical; same block halves, same nitrided or heat-treated crank (new are now nitrided again), same rods, same bearings. All you are doing by using stock 255 heads with EJ257 block is increasing your compression ratio and shortening the quench.

Option 1 from Kris is $3,000 if you supply him with you old block or $3,500 if not.
Add $330 for gasket/seal kit (from Kris) and $250 for ARP2000 head studs and you've got a solid and reliable street build for $3,500 (excluding labour and head work) 8)

* I say from 09-on because there was an issue with build of FXT/WRX 255 blocks in 2008 and I'm not sure if it affected LGTs, but know it didn't affect the STis (257s)
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Re: Best Value Light Rebuilt Engine Formulae

Postby bigBADbenny » Tue Jul 01, 2014 3:27 pm

Corrections, clarifications and suggestions very welcome here thanks :good:
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Re: Best Value Light Rebuilt Engine Formulae

Postby cynner » Tue Jul 01, 2014 3:31 pm

Who's Kris? :|
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Re: Best Value Light Rebuilt Engine Formulae

Postby blacktop™ » Tue Jul 01, 2014 3:38 pm

Kris is from Rising Sun Subaru
Image
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Re: Best Value Light Rebuilt Engine Formulae

Postby bigBADbenny » Tue Jul 01, 2014 5:12 pm

Yeah Sean: those figure were just parroted from the RSS site.
You're making it sound somewhat more attractive, please elaborate at will ;)
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Re: Best Value Light Rebuilt Engine Formulae

Postby cynner » Tue Jul 01, 2014 5:30 pm

What about with a pre-2009 ej255 engine?

I'm a complete n00b when it comes to engine builds. With Kris's custom engines here: http://risingsunsubaru.com.au/2-5L-Option-1.php - what is actually re-used from the stock engine? Both the block and the heads? Or does he take the stock block and build new heads? :blink:
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Re: Best Value Light Rebuilt Engine Formulae

Postby bigBADbenny » Tue Jul 01, 2014 6:10 pm

They're short blocks afaik.
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Re: Best Value Light Rebuilt Engine Formulae

Postby Sean82 » Tue Jul 01, 2014 10:26 pm

cynner wrote:What about with a pre-2009 ej255 engine?

I'm a complete n00b when it comes to engine builds. With Kris's custom engines here: http://risingsunsubaru.com.au/2-5L-Option-1.php - what is actually re-used from the stock engine? Both the block and the heads? Or does he take the stock block and build new heads? :blink:


bigBADbenny wrote:They're short blocks afaik.

Yes all short blocks, no oil or water pump though AFAIK.

As for pre-09, you don't want as a factory short; early 2.5L pistons are the worst I'm told. Subaru separated the rings a bit for later ones but not enough apparently.

As a platform for a light build (forged pistons only), they are good if you can find a really cheap, low use one. But, for the price, new or near-new is a better bet IMO.

The later years (09+) come with a hardened crank. Subaru firstly nitrided them, then for some reason (some time in 2010) switched to heat treating for a short while, then went back to nitriding. Hardened crank obviously has advantages ;)

Rods are no different from what I can find from my research.

Kris tends to use brand new short blocks for his Option 1 motors: CP 257 forged pistons with stock crank, rods, bearings, etc.
Re-use your peripherals and heads.

If you supply him with your old. Short block he uses these for Option 2 and custom build (option 2 include aftermarket rods and ACL race bearings instead of Subaru ones.

What I was planning for my old Foz (2011 S-Edition):

- Option 1 short from Kris ($3,000)
- Timing Belt kit ($550 from memory)
- Gasket/seal kit ($330)
- ARP 260-4701 head studs ($250 new or thereabouts)
- 11mm Oil pump ($275 from memory, could be wrong)
- Heads hot washed and "decked" ($350)

I was going to do the work myself saving a few dollars

My research showed this setup would be perfect for up to about 275, through a manual, or about 250 through an auto.
You could probably run a lot more with this setup (PCXT had his2006 Forester at 283kW with a Dom 2.5XT-R on 98RON running basically this plus ACL bearings for nearly 2 years or something...), but it would be more than adequately solid for sub-250.

As for the increase in comp ratio with 257 block and 255 heads, it's because:

255:
- piston dish 22 mm
- head combustion chamber 49cm

257:
- piston dish 19mm
- head combustion chamber 55cm

(Sizes are cubic)

Because of the piston dome size in relation to combustion chamber size, any decrease in the piston size will be exponentially greater than a change in the combustion chamber size...not something I'd personally do with stock pistons and head studs.

This is all just info I gathered from my research last year before offloading my Foz.
HTH
Sean..
Last edited by Sean82 on Wed Jul 02, 2014 11:09 am, edited 1 time in total.
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Re: Best Value Light Rebuilt Engine Formulae

Postby bigBADbenny » Tue Jul 01, 2014 11:21 pm

Thanks for sharing :)

LOVE IT!

Sean: what work were you going to, to save to save approx how many $$$?
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Re: Best Value Light Rebuilt Engine Formulae

Postby cynner » Wed Jul 02, 2014 9:31 am

Thanks Sean! Great info! :clapping:
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