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Old 03-17-2013, 06:04 PM   #1
morrocco88
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Default 07'-09' Legacy shortblock with phase I 2.5 DOHC Heads

I've searched a bunch and no specific help.

I have a 07'-09' phase II N/A short block with low low miles and want to put some 97' legacy DOHC heads on it. The thing I'm unsure of is if the pistons will work with those combustion chambers, as they pop up out of the block a little. I'm not worried about the compression too much, but rather if it will interfere or not.

Anybody been down this trail before?

Thanks!
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Old 03-24-2013, 07:14 AM   #2
JoshP
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Are the pistons domed? If so, then no they wont work. You can swap in P1 pistons and that will work.
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Old 03-24-2013, 08:35 AM   #3
Patrick Olsen
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The EJ25D pistons also protruded from the deck, too, but only by 0.05mm (which was less than the head gasket thickness by quite a bit).

How does the '07-09 compare to that?
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Old 03-25-2013, 02:00 PM   #4
morrocco88
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They seem to pop out past the Deck quite a ways. I've been told by another source that it will not work.

I just picked up a 99' Forester with a phase II EJ25 (spun bearing) with 53K original miles. If the heads look good, I might just use it for that....asuming it will work with those heads?
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Old 03-25-2013, 02:47 PM   #5
Matt Monson
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They'll hit. The newer 2.5i pistons are way too domed.
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Old 03-25-2013, 10:32 PM   #6
morrocco88
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Do you think it will work on a 99' forester with the first of the phaseII motors?
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Old 03-26-2013, 12:42 PM   #7
Patrick Olsen
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Yes. There are plenty of examples of folks using the DOHC heads on the '99-05(ish) Phase II blocks, myself included.
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Old 04-21-2013, 12:33 PM   #8
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Pat, the pistons dont protude, they are domed and the combustion chamber has a different shape. His '07 shortblock wont work with either set of heads he mentioned. Id be careful just throwing out incorrect info like that...

Heres a pic

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Old 04-21-2013, 05:23 PM   #9
Patrick Olsen
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Quote:
Originally Posted by JoshP View Post
Pat, the pistons don[']t prot[r]ude, they are domed and the combustion chamber has a different shape.
When you say "the pistons", I don't know which ones you're referring to since there have been 3 different short block varieties mentioned in this thread. The OP said the '07-09 pistons protruded from the deck; if you disagree with that information, then correct him. The only statement I made was about the EJ25D pistons, which do protrude 0.05mm from the deck. You can find that information in a variety of places on this forum. The math (courtesy of TWE): 30.3mm piston compression height + 131.25mm rod length + 1/2 the stroke = 201.05mm. Deck height is 201mm.

Quote:
Originally Posted by JoshP View Post
His '07 shortblock won[']t work with either set of heads he mentioned.
I never said it would. I did say that Phase I DOHC heads will work on an early Phase II block, since the OP asked about using the heads on a '99 Forester short block. Subaru built engines like that in '98 and '99, and I and a number of others have built engines like that.

Quote:
Originally Posted by JoshP View Post
I[']d be careful just throwing out incorrect info like that...
If you can point out what I said was incorrect, that would be great.
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Old 04-21-2013, 06:24 PM   #10
FuJi K
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Let me at those newer pistons with my porting bit. I'll make it work!
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Old 04-21-2013, 06:57 PM   #11
JoshP
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Quote:
Originally Posted by Patrick Olsen View Post
When you say "the pistons", I don't know which ones you're referring to since there have been 3 different short block varieties mentioned in this thread. The OP said the '07-09 pistons protruded from the deck; if you disagree with that information, then correct him. The only statement I made was about the EJ25D pistons, which do protrude 0.05mm from the deck. You can find that information in a variety of places on this forum. The math (courtesy of TWE): 30.3mm piston compression height + 131.25mm rod length + 1/2 the stroke = 201.05mm. Deck height is 201mm.


I never said it would. I did say that Phase I DOHC heads will work on an early Phase II block, since the OP asked about using the heads on a '99 Forester short block. Subaru built engines like that in '98 and '99, and I and a number of others have built engines like that.


If you can point out what I said was incorrect, that would be great.

a '99 shortblock was never mentioned, only shortblock he ever asked about was the '07. He clearly mentioned that his '99 Forester has a spun bearing... You obviously misread into that post.
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Old 04-23-2013, 09:01 PM   #12
morrocco88
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So the 07' shortblock won't work with the 99' Forester heads either? I'm just about to tear into this project and hoped the 07' block would make it duck soup.
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