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Old 08-09-2009, 02:10 PM   #1
glen
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Default Build an EJ205 with an EJ20H Shortblock?

So I'm rebuilding a 03 WRX and the block is cracked. I have a complete EJ20H longblock and I'd like to make one motor out fo the two. I think from what I've read that I can simply break the EJ20H down to the shortblock and then I should be able to put the EJ205 heads/intake etc on it, correct?

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Old 08-09-2009, 02:11 PM   #2
Marnix
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Yes but you must use the EJ20H head gaskets, part number is 11044AA355 and you can get those in the US.
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Old 08-09-2009, 02:13 PM   #3
glen
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Good thing I didn't buy headgaskets yet, thanks. What's the difference? compression?
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Old 08-09-2009, 02:14 PM   #4
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Thickness (about 0.6 mm difference) when you use the stock WRX gaskets the pistons may hit the cylinder head when the engine is cold.
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Old 08-09-2009, 02:23 PM   #5
glen
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Thanks again, searching for that number turned up lots of useful info, but most of the info I find here is for EJ20G or EJ20K are there any differences in the shortblocks of thse and the EJ20H that I should know about, or all they all pretty much the same?
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Old 08-10-2009, 01:06 AM   #6
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Pretty much the same although some EJ20K's have forged pistons ex factory. Main differences between EJ20G and EJ20H shortblocks are compression ratios, they can range from 8.0 to 9.0.
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Old 08-02-2011, 05:54 PM   #7
JD02BugEye
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sorry to dig up an ancient thread but i was told the ej20h had a better oiling system than the stock 02-03 wrx. any truth to this?
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Old 08-02-2011, 06:16 PM   #8
Matt Monson
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Quote:
Originally Posted by JD02BugEye View Post
sorry to dig up an ancient thread but i was told the ej20h had a better oiling system than the stock 02-03 wrx. any truth to this?
Define better oiling system? I once heard a rumour that some of the open deck Ej20H's has piston squirters like a closed deck block. Other than that, I can't think of anything different that could conceivably be considered "better oiling"...
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Old 08-02-2011, 06:43 PM   #9
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Quote:
Originally Posted by Matt Monson View Post
Define better oiling system? I once heard a rumour that some of the open deck Ej20H's has piston squirters like a closed deck block. Other than that, I can't think of anything different that could conceivably be considered "better oiling"...
the squirters is not just a rumour, i have one in my garage that is an open deck EJ20H motor that has oil squirters.

dont know if its any better. just know that it is a fact...

-=Suberdave=-
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Old 08-02-2011, 08:12 PM   #10
jdmwrx94
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by squirters, do you mean holes around the piston at the lower ringland? if so mine has lol
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Old 08-02-2011, 09:22 PM   #11
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Quote:
Originally Posted by jdmwrx94 View Post
by squirters, do you mean holes around the piston at the lower ringland? if so mine has lol
No. Squirters look like the valve inside the valve stem on your tires. It's located behind the piston threaded into the block casting.
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Old 08-03-2011, 02:29 AM   #12
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Standard on all closed deck EJ20G blocks and a very, very rare option on some early open deck blocks. I've seen them only on one STI open deck block (pre 1996) so I can't comment on EJ20H blocks.

The oiling system is idetical for all EJ series engines only difference if various sizes in oil pumps and cross drilled cranks on some (JDM) engines. The main principle/concept is the same for all engines though.
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Old 08-03-2011, 04:07 PM   #13
Matt Monson
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Quote:
Originally Posted by suberdave View Post
the squirters is not just a rumour, i have one in my garage that is an open deck EJ20H motor that has oil squirters.

dont know if its any better. just know that it is a fact...

-=Suberdave=-
Dave,
You should know by now that I won't call anything a fact with respect to these cars if I haven't witnessed it firsthand or have a document to back up the claim. Douglas Vincent said he had an Ej20H with them, which I take a pretty reputible source. But I'm not going to put my name to a spec unless I know 100% that it's true. Even with your 2nd testimonial on top of Douglas' I'll call it a rumour next time it comes up because I have never laid my eyes on one, and I've torn down maybe half a dozen Ej20h's and have never seen them. That says to me it's definitely not on ALL of them.
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Old 08-17-2011, 01:01 PM   #14
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Quote:
Originally Posted by Matt Monson View Post
Define better oiling system? I once heard a rumour that some of the open deck Ej20H's has piston squirters like a closed deck block. Other than that, I can't think of anything different that could conceivably be considered "better oiling"...
yes that is what i was told. i had an ej20h block put in my car and used all of my usdm accessories and heads. the guy told me the oiling system was better and they dont spin bearings as easily because of the oil squirters.
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Old 08-17-2011, 02:14 PM   #15
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He wanted to give me a 20h I got the g instea and it now uses a 20k STi ecu
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Old 10-21-2011, 07:46 AM   #16
STIll inspired
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i have been under he impression that using ej205 heads on older ej20s including the ej20h would drop the compression ratoio to 7 something. isthis true?
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Old 10-21-2011, 11:28 PM   #17
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bumpin for info
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Old 10-22-2011, 01:41 AM   #18
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No. Using EJ205 heads instead of EJ20G/H/K/R heads lowers the compression only 0.3 when using the EJ20G/H/K/R head gasket thickness (1.4 mm you cannot use the thinner 0.8 mm EJ205 gasket). And while EJ20H either have 8.5 CR (up to 1996) or 9.0 (1997-1998) this is OK.
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Old 10-22-2011, 07:38 AM   #19
STIll inspired
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would it be wise to get a custom head gasket or use the stock headgasket. also what if i was to make a 2.1 stroker build with it how would yoiu advise in doing so. my goal is to get better low end power as the 2.1 stroker does in order to have better acceleration out of the twisties and better cruising mpg.
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Old 10-23-2011, 02:03 AM   #20
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Why go custom for head gaskets? There are many good off the shelf options. OEM EJ20K/EJ20R gasket is the best MLS gasket 1.4 mm thick there is but expensive to source in the US. Alternatively you can use a Cometic with correct thickness.

For a stroker build you should obtain information from your engine builder. If you intend to build the engine yourself, do extensive research to draw a list of parts you need. If you can't figure out what you need don't build the engine yourself (not flaming just warning for imminent disappointment).
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Old 10-23-2011, 10:18 AM   #21
STIll inspired
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thanks i gotcha. i have been looking into the 2.1 stroker and have heard so scarry things. i asked about a custom headgasket knowing/thinking about the older headgaskets failing. i know the early 2.5 headgaskets and the thicker 2.2 gaskets used to fail. i understand the gaskets are getting better now i rarely hear of headgasket problems from 2002 and up. i am going to mostlikely use a cometic or custom head gasket just for the fact i want to run a higher compression for a little more grunt in the bottom end as this will be a conservative build.
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Old 02-03-2021, 01:18 PM   #22
BronzyWizard41
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Just wondering is this would work in reverse? Ej205 with ej20h heads? As I have an ej20h but the bottom end is cooked and I'm just wondering if I could put my head's and such on a 205 block and put it back in the car and run it out its there something in missing
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Old 02-10-2021, 04:02 PM   #23
SoCoNoHa
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I could've sworn that in the phase 1 blocks the pistons are just shy of the deck at TDC, whereas in phase 2 motors they protrude from the deck at TDC, maybe I've got it backwards. I had EJ25D heads on a 257 block, and she tapped the whole time. I never saw evidence of valve to piston contact, but that's definitely what it sounded like.
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