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Old 02-18-2004, 08:22 AM   #1
Scooby Newbie
Member#: 53595
Join Date: Jan 2004
Chapter/Region: NWIC
Location: nowehres
1987 GL Hatch
EA81 1.6L + Weber


Well, I'm still fairly new to EJ engines. Been in the EA engines for a while though. (80s subes)

What, if any, engines in the US market were DOHC? I know you can get JDM engines as DOHC.

Also, how much harder are they to work with (work on) and is there a beneficial increase in power and/or other benefits that really stand out over single came systems?

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Old 02-18-2004, 08:50 AM   #2
1 Lucky Texan
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Phase I 2.5l I think. My H6 3.0 is DOHC.
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Old 02-18-2004, 11:44 AM   #3
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Chapter/Region: MWSOC
Location: Clarendon Hills, IL
2007 Legacy GT
Brilliant Silver Metallic


Just to reinterate on what a lucky texan once said, the phase I 2.5 liter from 97-98 Impreza RS's were DOHC.
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Old 02-18-2004, 01:15 PM   #4
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Location: Ottawa, Ontario, Canada
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and the Legacy and Outback had the DOHC till 2000.... In 2000, they were switched to SOHC...

Foresters were till 1999.... like the impreza....

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Old 02-18-2004, 01:35 PM   #5
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Join Date: Oct 2001
Location: Ontario
1997 GF4-STiV3 clone


The turbo engines are DOHC.

The DOHC 2.5 make better power a high revs but lags behind for the rest of the range. They also tend to blow headgaskets far more frequently. You can buy them a lot cheaper because of this problem.
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Old 02-18-2004, 03:15 PM   #6
Section 8
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Location: "Like a hyena you are..."

To clarify:

The DOHC makes a MINIMAL increase of power over the SOHC at higher REV ranges. ON the oreder of a few horse power. The head gaskets were the problem, not a design flaw with the engine. If you put the updated gaskets in the car, there are no problems with them.

If you want to go fast, cams for the DOHC can cost up to twice as much as the SOHC. THe SOHC heads have threaded adjusters for cam to lifter adjustments. THe DOHC uses shim over bucket which is alot more of a pain in the butt to do, and isn't optimum for higher redlines. If you want to run higher redlines, there are shim under bucket conversions for $1000.00 or more to allow you to do this.

If the extra money spent is worth the ability to change the individual cam degrees, then you need to purchase cam gears that are really expensive and hard to find. A place in australia was going to make some for $400.00, but the aparently never have. The only other cams I know of are Toda and Cusco (I think) that make cam gears that will fit the DOHC heads. You can probably get them made for you for less than those to companies.

For an all out project they would be great, for a more budget minded project, stay away. I was looking into DOHC heads, it would be great, but if I could afford all of the extra stuff, I wouldn't be driving the Subaru in the first place.

You might be different, so go where you wallet leads you.


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Old 02-18-2004, 10:48 PM   #7
Matt Monson
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99 2.5RS, '85 911
'73 914 and 2012 BRZ


That should keep you busy for a bit...
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