Phase I EJ25 block with Phase II EJ25 heads?

[idosubaru]

Will it work? I already searched at NASIOC (main thread is 14 pages) and here nd it's not covered since they're all going the opposite way. I know i've seen folks (subaru360 i think) comment on it here but can't find the posts.

 

Pistons clear the deck on the Phase I EJ25's....so....does that prevent Phase II EJ25 heads from working on it?

 

Gloyale doesn't think it will work:

http://www.ultimatesubaru.org/forum/showthread.php?t=114580&highlight=Phase+block

 

side note:

Do Phase I EJ22 pistons clear the deck face too?

Edited March 11, 2011 by grossgary

[idosubaru]

The thickest gasket cometic offers is 140 thousandths, or 3.5mm's - over twice as thick as the stock 1.52mm's. I wonder if an extra 2mm's would be enough to gain the necessary clearance?

 

Is there anyway to measure/check this without buying/trying them?

 

Cometic said they could figure it out if I knew the cc's of the EJ25D head and the cc's of the SOHC EJ25 head. Where can I find that, the FSM doesn't have it?

[WJM]

11044AA610 gaskets and it'll work.

[idosubaru]

11044AA610 gaskets and it'll work.

Are you sure will that SOHC heads on DOHC block? Just checking since Gloyale said his wouldn't work?

[WJM]

Not really. I've never tried it. I give it a 90% chance of success.

[idosubaru]

Not really. I've never tried it. I give it a 90% chance of success.

That gasket is 1.4-1.5 mm thick. Cometics offer 3.5 mm thick gaskets. So %95 chance with the thicker ones? LOL Strange no one but Gloyale has looked into it.

Edited March 11, 2011 by grossgary

[WJM]

That gasket is 1.4-1.5 mm thick. Cometics offer 3.5 mm thick gaskets. So %95 chance with the thicker ones? LOL Strange no one but Gloyale has looked into it.

 

1.05mm thickness for the 642 gaskets.

1.70mm thickness for the 610 gaskets.

 

I would say that since the 97~99 DOHC heads with a 642 gasket do not work (piston hits the head) and the 610 gasket enables it to work (since its the stock replacement)...that the SOHC heads with the 610 would work.

 

The combustion chamber CC: I think the SOHC has a little more since the shape is different than the 97~99 DOHC heads.

 

The pistons on the SOHC phase 2 do not come out of the block.

The pistons on the DOHC phase 1 97~99 do come out of the block.

 

Both DOHC and SOHC, IIRC, have the similar valve seating positions but at slightly different angles.

 

I dont think there is a significant enough change in timing/lift/duration to cause a concern.

 

 

And most of all, I would *NEVER* use a cometic MLM gasket in place of a SUBARU MLM gasket.

I would use the cometic MLM in place of a composite/non-metal type gasket.

[idosubaru]

thanks will for offering up some thoughts.

 

I would say that since the 97~99 DOHC heads with a 642 gasket do not work (piston hits the head)

so DOHC heads won't even work on DOHC engines with that gasket?

that might convince me to try it, what's going to break the head or piston or both? LOL

 

why does subaru offer two different gaskets?

 

I think Gloyale thought the DOHC valve reliefs would not "line up" with the SOHC valves.

 

 

The combustion chamber CC: I think the SOHC has a little more since the shape is different than the 97~99 DOHC heads.

i saw 46.2 for DOHC and 50 for SOHC. Edited March 11, 2011 by grossgary

[WJM]

so DOHC heads won't even work on DOHC engines with that gasket?

 

With the 642 gasket, indeed not.

 

that might convince me to try it, what's going to break the head or piston or both? LOL

 

Just do it.

 

The engine will turn over freely by hand, but when you start it up it sounds like horrible multiple rod knock. After 10 seconds of running, there was no damage to be found, but you could see on the piston and head where there was contact.

 

I took that engine back out and put 610's in it and it was fine after that.

 

why does subaru offer two different gaskets?

 

They don't.

 

The 610 is stock replacement for the 1996~1999 DOHC EJ25D.

 

The 642 is stock for the 2004~2006 EJ257, 2004~2005 EJ255 in the Forester/Legacy/Outback turbo and the 2004~2006 EJ255 in the Baja turbo.

In 2006, all EJ255 (except BAJA) went to "improved cooling" and the part number changed to a 670 (and later 770) as the coolant passages changed. Same for 2007 and up STi. DO NOT use the 670/770 gasket in place of the 610/642/633 gasket and vice versa as it will result in overheating.

 

I think Gloyale thought the DOHC valve reliefs would not "line up" with the SOHC valves.

 

They probably dont.

 

i saw 46.2 for DOHC and 50 for SOHC.

 

Close enough.