Remove EJ25 II SOHC head w/o disassembling?

[NLSA]

I have a 2000 Outback whose head gaskets finally failed at 195K. The engine is a Phase 2 SOHC EJ25. I have removed the engine and stripped off the intake manifold. Now it's time to get serious.

 

This is my first big car project so forgive me if my question is stupid.

 

The service manual (which I think is the correct one but I'm not 100%) says to disassemble the cylinder heads, remove the camshaft, etc. in preparation for removing the heads. However, it looks to me like I could leave the head intact and just remove it in one piece. Is this a bad idea?

 

And by the way, what exactly are the head bolt heads? Torx Plus 24EP, is that right? If so, where can I get a proper tool?

 

Thanks-

MRO

[xman]

Just take off the timing belt and leave everything else as it is. No need to disassemble further.

 

For the bolts use a 12 point metric socket that fits (I don't recall the size off hand), works perfectly.

[Fairtax4me]

Head bolts are 12 point 14mm IIRC.

edit: thought I read DOHC somewhere...

SOHC I don't think you need to remove the cam, but if you need to have it machined it's a good idea.

[NLSA]

Head bolts are 12 point 14mm IIRC.

edit: thought I read DOHC somewhere...

 

This threw me at first, too, because so many internet sources showed DOHC images as "EJ25". There is only one pulley & camshaft on each side of the engine so mine must be SOHC.

 

If someone could tell me the visual difference between an EJ251 and EJ252, I'd appreciate it.

 

Thanks again-

MRO

[Qman]

There really isn't a difference. SOHC is anything after '99.

[tomson1355]

MRO,

 

Visually the Phase I DOHC has two bumps on the timing cover on each side of the engine. The Phase II SOHC has one on each side. You certainly have the Phase II SOHC on a 2000 Outback. The plugs are angled up on the Phase II rather than horizontal as on the Phase I, which makes them much easier to change.

 

Get a 1/2" drive 14mm 12-point socket for the head bolts. Your manual should have the proper torque sequence.

 

Good luck with your project. Don't sweat it. It's not that hard.

 

Tom

Earlville, NY

[Danbob99]

The SOHC engine heads can certainly be removed with the cam boxes and cams still installed.

 

I would actually recommend leaving them on. It's a pretty lengthy process to take them apart and clean all the silicone. If you do have them apart though, the manual outlines an incorrect procedure for resealing the cam box to the head. You need to run sealant all the way to the cam journal (the fsm has you stop 1/8" short of the cam journal)

 

Anyways, you can leave them on, and I would recommend doing so.

 

Dan

[211]

This is more a question for my own sake, but if you leave the cam blocks intact and have them machined. will they disassemble them at the machine shop and reseal and reassemble them after cleaning?

Soon I too will be doing the heads in my 2000 obw...

[Danbob99]

This is more a question for my own sake, but if you leave the cam blocks intact and have them machined. will they disassemble them at the machine shop and reseal and reassemble them after cleaning?

Soon I too will be doing the heads in my 2000 obw...

 

 

As long as a maching shop is familiar with the Subaru head, they will not need to disassemble the cam box. The only reason they do on many other makes is to ensure all valves are closed. This is not necesary on the Subaru heads. So no, they will most likely not need to remove the cam boxes. Just make sure you clean any residual metal shavings out of the head after machining.

 

Dan

[Gloyale]

The Machinist will need to remove the cam boxes in order to locate the head properly.

 

Most likely they will charge you for this, espescially if you have them reassemble them.

 

I would suggest letting the machinist take the cam cases off, because the torx and Allen head bolts they are held with are often stubborn and strip or will break cheap torx sockets.

 

I recommend waiting until the heads are on the engine (engine out of car) before resealing the cases to the heads.

[Danbob99]

The Machinist will need to remove the cam boxes in order to locate the head properly.

 

This is not correct for all machinists. I work with several in the local area that have manufactured jigs to hold the PHII heads with cam boxes intact. This is why I recommended trying to find someone that is familiar with machining the Subaru head.

 

Dan

[Gloyale]

This is not correct for all machinists. I work with several in the local area that have manufactured jigs to hold the PHII heads with cam boxes intact. This is why I recommended trying to find someone that is familiar with machining the Subaru head.

 

Dan

 

You're machinist is full of it then. I frankly just don't believe that a machine shop would do that. Would you be willing to name this shop?

 

Anyway, let's eximine the possibility.

 

There is nowhere on the cam case that has a machined flat and true face to locate off of. So they would have to be using bolt holes on the sides of the head. This means the whole deal is dependent on those side holes being EXACTLY 90 degrees from the head face. Which leaves all sort of possibilitys for misalignment. This is the same reason that you can't surface Subaru blocks without splitting them to locate off of the Main Bearing faces. You have to be able to mount the block (or head) FIRMLY to a known true surface.

 

I wouldn't want a head that was chucked into a jig, rather than properly disassembled for proper machining. It just isn't worth it. And I can't imagine that a Machinist would go to the trouble to make a jig to lose money.

 

The only true and proper way to machine those heads is with the cam case removed. And any good Machinist would simply unbolt the case and charge for the small amount of labor rather than make a one off jig, contrary to recommended proceedure.

 

It would not be in their interest to make the job harder for them (making the jig) and easier for you (no need to reseal). It would put the quality of the work, and their reputation at risk.....for no benefit for them.

Edited November 2, 2010 by Gloyale

[Fairtax4me]

Wouldn't the intake and exhaust port sealing surfaces be 90° to the block surface?

[Gloyale]

Wouldn't the intake and exhaust port sealing surfaces be 90° to the block surface?

 

In theory. However those are relatively small surfaces to locate off of. ANd with all the trouble with Subaru HG's, you NEEED these heads to be perfectly flat.

 

You'd have to bolt the head into a jig that holds the head above the surface of the Mill. And the pressure of the Mill head pretty strong, I could see it easily shifting the head within the jig if the head itself can't be supported from underneath.

 

The way that ERA (Engine Rebuilders Association) and Subaru recommend is to remove the cases, and clamp the head directly on the mill, and do it that way.

 

I would not want heads done any other way. The heads I get back from my machinist (Bob Forrest Machine, best in the Willamette valley) look like glass, and none have failed after 3+ years.

[211]

Don't they have to tear the head down anyway to replace the cam and valve seals? Or is this a 'requested' service? I always thought it was implied, when you take your heads in to have them machined they clean and reseal them too.

[Gloyale]

Don't they have to tear the head down anyway to replace the cam and valve seals? Or is this a 'requested' service? I always thought it was implied, when you take your heads in to have them machined they clean and reseal them too.

 

Most places will charge extra for a Valve Job and Stem reseal.