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Old 02-13-2006, 11:36 PM   #1
porscharu
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Default 98 2.5 l dohc ?

well i wont go to far in to it but i have a porsche 914 running a 98 2.5 l dohc motor, my timing belt broke. i dont know if it did any damage, but i would like to convert to a sohc any ways. so will any sohc head bolt to my dohc block and will it work with the stock ecu. i have never had an over heating problem but if i can fix that too when the heads are off it would be nice

TIA
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Old 02-14-2006, 03:34 AM   #2
Storm
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At least some of the valves will be toast. Depending on how lucky you are...you may or may not have (terminal) piston damage. You can put SOHC heads on the current block...but you may be better off using a SOHC longblock assembly. The intake manifold will need to be from a SOHC but you can still get it to run off the current sensors.
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Old 02-14-2006, 11:28 AM   #3
Matt Monson
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As mentioned, you will need to change the intake manifold, and I don't know of anyone who has been able to get the DOHC Ej25 ECU to run a SOHC correctly.

Also, your bottom end is phase I with a center thrust bearing. In light of the incident, I would seriously consider a complete SOHC Ej25, which would be phase II. If $$$ prohibit the conversion, find a good used phase II bottom end and have your DOHC heads rebuilt.
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Old 02-16-2006, 10:40 AM   #4
steve_d
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bummer. I'd just swap out to a SOHC short block...look for someone who's doing a swap. or look for a 2.2L and go turbo.

sjd
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Old 02-16-2006, 12:23 PM   #5
Matt Monson
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If you put a phase II Ej25 bottom end against thos heads, you get a nice little CR bump putting you up around 11:1. With a set of Delta Camshafts ($350) you will be right around 210hp or so, maybe even more with your set up. I saw a dyno sheet of Poruki's 911 w/EJ25 yesterday, and because of his Weber carb and custom exhaust for the 911, he's way above stock Ej25 numbers without internal modifications.

Or, if you put an Ej22 bottom end against those heads, you will see about 8.6:1 and be ready for a nice little boosted set up. With the DOHC Ej25 ECU, you can run a turbo using an AFC and RRFPR as the most basic of "EM" and get away with it...
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Old 02-16-2006, 02:48 PM   #6
steve_d
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the poruki weber setup is soooooo cool. looks shockingly like a type IV.

sjd
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Old 02-16-2006, 03:22 PM   #7
Matt Monson
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Yeah,
Wayne does nice work. I was going to ask him to build me a set for my 914 until I sold it...
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Old 02-16-2006, 05:34 PM   #8
Jaxx
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link? to said car?
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Old 02-17-2006, 09:18 AM   #9
poruki
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Old 02-17-2006, 10:48 AM   #10
Storm
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OMFG!!!!!!

That's beeeautiful!
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Old 02-17-2006, 04:48 PM   #11
yebokmj
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I might have just what you looking for. I have an MY97 DOHC with a PHASE II 2.5 shortblock from an MY00 It has about 10k since it's been rebuilt and had the head O-ringed. I took it out for my engine swap. I just want to get rid of it PM me an offer if it's of interest to you.
Joshua
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Old 02-20-2006, 11:47 AM   #12
Growit
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Default Phase2 block Phase1 heads

I posted something a little earlier about MY05 Short Block and MY96 Heads.

With the head gasket problems and old blocks wearing out. I'm going to guess alot of people are asking/or going to be asking the same questions in the near future.

For a daily driver:

With that kind of CR and the problems with Phase1 blown head gaskets would you ring the heads or the block? Does it matter which you ring?

Using the .151 head gaskets, would you use Subaru stock or pick another brand (which one would you use)?

Would the short block hold up?

What cam profile would you ask for from Delta cams?

Stock MY96 ECU handle the new setup?

What suprises lie in store for me with this setup?

Or would I be better off using the pistons from the Phase 1 (if they would even bolt up)

The block is bought so now I have to decide what to do with it.

Thanks for your knowledge.
Mike Barrington

Last edited by Growit; 02-20-2006 at 12:00 PM. Reason: add more
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Old 02-20-2006, 06:38 PM   #13
yebokmj
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You don't need to ring anything. I O-ringed mysetup because of boost. The new DOHC gasket doesn't have problems like the origionals. I used the factory DOHC gasket without problems but that was on an MY00 block I don't know what changes have been made in MY05. The shortblock will hold up fine. I don't see why you need new cams. Your stock ecu should be fine though you could probably benifit from the bump in compression if you use some piggy backs. Shouldn't be any kind of suprises or a need to switch pistons.
Joshua
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