06 outback 2.5i AVLS cracked cylinder head - what fits?

[jamesm113]

Have an 06 outback 2.5i (non-turbo), with a cracked driver side cylinder head.  One cylinder has 2 cracks between the spark plug hole and both intake valve seats, the other cylinder has 1 crack between the spark plug hole and an intake valve seat.

 

Looking to get a replacement cylinder head, but would like to know what fits.

 

Subaru parts say it fits a handful of 06-07 outback/legacy models only (no forrester, impreza, etc). 

 

I know 05 won't work, because 06 has the AVLS rockers, and assemblies that need to bolt into the head.

 

I've also seen some warnings with the exhaust manifold. I have the 3 stud exhaust manifold, but there are some variations out there with 4 studs

 

According to this post, only the casting and cams changed for 08-09 outbacks/legacys, so those should fit fine.

 

Looking at part numbers (drivers side head):

 

11063AB27A - 06-07 Outback / Legacy - "V25" head

11063AB43A - 08-09 Outback / Legacy - "T25" head

11063AB310 - 06-07 Impreza / Forester ??

11063AB430 - 08-11 Impreza / 08-10 Forester ??

Edited December 8, 2017 by jamesm113

[GeneralDisorder]

If it passes a pressure test, use it. Cracks between the valves are not uncommon and are typically not an issue.

 

GD

[jamesm113]

It failed the pressure test. Exhaust valves are bad too...

[GeneralDisorder]

If it got hot enough to cause that much head damage - I would be worried about the bottom end. Cut the oil filter and pull the oil pan. Almost certainly going to need rings as they will have lost their tension and are probably full of carbon. 

 

GD

[jamesm113]

Good idea, I'll check that.

 

I've only owned the car for 5 thousand miles or so. I've hit as high as 228F according to my OBDII gauge, which is about 3/4 of the way up, before I had a chance to pull over. Never in the red under my watch. The car would only overheat going up long grades. Never overheated in traffic/on flat land.

 

Exhaust valves were pitted pretty badly.

 

Car ran fine otherwise when I pulled the heads. Was thinking it would just be a head gasket job. Was leaking oil externally.

 

Any tips on cylinder head compatibility?

[idosubaru]

Did you pull the other cylinder head and check it or are you just swapping one head?  I'd be checking the other head.

 

www.car-part.com and see what interchange as a starting point

pictures on ebay and google image search can show the stud differences

or look up exhaust manifold and intake manifold gaskets and compare the bolt pattern. 

 

 

If it got hot enough to cause that much head damage - I would be worried about the bottom end. Cut the oil filter and pull the oil pan. Almost certainly going to need rings as they will have lost their tension and are probably full of carbon. 

 

GD

 

+1. 

engines with abnormal overheating symptoms like cracked heads or wavy timing covers, or melted knock sensors are good at loosing rod bearings shortly after a head job.

[jamesm113]

The other head was checked by the machine shop. Pitted exhaust valves, but no cracks.

 

I pulled the knock sensor and timing covers - both looked normal to me. No melted knock sensor or wavy timing cover.

Edited December 8, 2017 by jamesm113

[jamesm113]

What exactly should I be looking for when pulling the oil pan and cutting open the oil filter?

 

I don't have a straight edge (arrives in the mail tomorrow) yet, but using a level or a ruler, it looks like the cracked head is just above the warpage limit.  A .03mm (.001") feeler gauge drags slightly in between the cylinders.  A .04mm (.0015") feeler gauge does not fit.

 

For what it's worth, the cylinder cross-hatching looks good, none of the timing covers look melted, and the knock sensor does not look melted.

[jamesm113]

Oil filter open.  Looks normal to my untrained eye.

 

EDIT:  I also cut a slice of the paper element out with some dikes and ran a strong magnet along both sides of the paper filter.  It didn't pick up any metal shavings, nor did I spot any.

Edited December 9, 2017 by jamesm113

[rocketman]

I am sure some will show up to tell you more, what I'd you use to cut filter open?

[jamesm113]

I used tin snips around the base of the filter and a flat screwdriver to pry it apart

[idosubaru]

Good job. Look for metallic flakes in the oil.

 

They almost always have the original cross hatching in the cylinders, probably forgetting one but don’t think I’ve ever seen one that hasn’t except for damage from blown blocks - busticated rods and pistons.

[GeneralDisorder]

Cross-hatching is meaningless. They all retain this. For that matter my 99 Chevy Vortec with 177k on it still has it too. Its not unique to Subaru. It also doesn't mean the bores don't have wear.

 

When you cut the filter you are looking for metal in the canister - it usually settles on the bottom - or between the pleats of the element.

 

GD

Edited December 9, 2017 by GeneralDisorder

[jamesm113]

Oil pan removed.  Everything looks normal to my untrained eye, no metallic flakes.  Screen looked clean.  I noticed some varnish on the pickup tube assembly, and a little bit of gunk right below the oil pan. 

 

Inside the oil pan was very clean too.  Saw no shavings, etc.

 

Nothing at the bottom oil filter canister.  No metal, shavings, etc - just oil.

 

I'm really hoping this is a good sign that bottom end failure is not imminent.

 

 

 

Looking a step ahead, anyone know about interchangeability between the subaru heads?  Obviously I need an AVLS head (ie. 2006 and newer heads only).  I have a good lead on a set of heads from an 07 impreza.  I know the cams aren't a match, nor is the head itself, but I'm thinking the head body would be good.

 

EDIT: No shavings between the pleats of the filter element either.

Edited December 10, 2017 by jamesm113

[jamesm113]

Searching car-part, it only interchanges 06-07 outbacks and legacys, which matches the subaru part #11063AB27A (casting V25).

 

Looking at eBay listings for imprezas/foresters, if the donor impreza/forester is an 06-07 (subaru part #11063AB310), the casting number is V25.  If the donor impreza/forester is an 08-09 or later, the casting number is T25, which matches the 08-09 outback/legacy casting heads.

 

Looking at RockAuto, "Famous Brand" 2713JL/2713GR  and "Crankshaft supply" SU2505 / SU2506 list pretty much all EJ253-equipped models between 2006 and 2011 (Foz 06-10, Impreza 06-11, leg/outbac 06-09).  They list V25, T25 and E25S.

 

So I'm about 90% sure an 06-07 impreza/forester head would be a match, just would love to know why subaru has two different part numbers between the legacy/outback and impreza/forester.

 

Looking at the Subaru parts diagrams (06 outback, and 07 impreza), there are a few extra parts on the 06 Outback - the straight pin on the camshaft cap end, and the two plugs on each of the head.

 

Exhaust manifold gaskets, intake manifold gaskets are the same.  So are the cam seals and plugs.  Sprockets are different, but cam sensor and its holder are the same.

Edited December 10, 2017 by jamesm113

[GeneralDisorder]

06 to 10 have the same heads. Its not till 11 they changed a bunch of stuff.

 

Sounds like it's ok. Change the piston rings and clean out the oil control drain back holes in the skirts, etc. Feel the rods when you have the pistons out - if there is any tightness in any of then it means the bearing insert is collapsing and grabbing the crank. They should flop around with virtually no friction.

 

GD

Edited December 10, 2017 by GeneralDisorder

[idosubaru]

I don’t know interchanges on 05+ but id expect 06-09 to all be be interchangeable. Subaru is always using different part numbers, they change them all the time. Most parts that interchange don’t have the same part number.

 

With www.car-part.com you can have one of the cheapest ones in the country shipped to you.this makes it easier as you can get the exact part you need, not take a chance, and still get a great price if that’s your main motivation.

Edited December 10, 2017 by idosubaru

[jamesm113]

06 to 10 have the same heads. Its not till 11 they changed a bunch of stuff.

 

Sounds like it's ok. Change the piston rings and clean out the oil control drain back holes in the skirts, etc. Feel the rods when you have the pistons out - if there is any tightness in any of then it means the bearing insert is collapsing and grabbing the crank. They should flop around with virtually no friction.

 

GD

How difficult of a job is it to change the rings?  Reviewing the FSM, it says I need some speciality tools that I don't have.  I see the 4 access ports, but don't see much on the forums on how to do the job...

[jamesm113]

Also, I just noticed one of the exhaust valve guides is in the wrong position on the cracked head

 

EDIT - add second photo from exhaust port.

Edited December 11, 2017 by jamesm113

[GeneralDisorder]

Yeah the dropped guide is a common issue. Does require changing the head.

 

There are no special tools required. You can knock out the wrist pins from the opposite side using a long 1/4" extension. Needle nose pliers for the wrist pin clips. 14mm allen for the access plugs. 

 

GD

[jamesm113]

Copy that. Standard size rings have been ordered. Any advice on making sure the connecting rods don't damage the cylinders when rotating the crank? It seems like the rod could scratch the cylinder pretty easily without the piston.

 

Do you normally have to shave off any material on the piston rings after checking the clearance in the cylinder?

 

Should I leave the oil pan off for this job?

[GeneralDisorder]

Pan off, yes.

 

The rods won't hurt the cylinder if you are careful. Don't worry about it.

 

Ring end gap is typically not an issue on stock sized rings. Could depend on brand though so best to check. I find I only have to adjust on oversized or ultra high performance applications (over 400 HP).

 

GD

Edited December 11, 2017 by GeneralDisorder

[jamesm113]

Thanks GD. 

 

Checked the block tonight with a straight edge tonight, looked like both sides were warped the short way between .001" and .002".  Any recommendations there?  Put the block on top of glass and sand?

[idosubaru]

That’s what we do with heads and you should with heads as well.

 

Great to get the block finish right as well but I’ve never done it and wonder if there’s concerns about getting debris inside critical areas during the process. I guess it would just be the oil supply channel to the heads. Prefill hole with something to keep debris from propagating? GD or someone else will know.

Edited December 12, 2017 by idosubaru

[jamesm113]

Finished resurfacing the heads tonight (did 220 grit->320->600 on a 12"x10"x1/2" piece of glass) and pulled 2 pistons.  I stripped the Cyl #4 screw pretty good and broke a screw extractor trying to pull it out.

 

There's some side to side play (ie towards the front/back of the engine) on the connecting rods, but it's smooth going up/down, and there's no play going in/out.  Hope that's a good sign, but would love input from others on that.

 

My only experience with rod bearings is when my dirt bike's rod bearing seized.  It was definitely not smooth  I purchased a junkyard bottom end, but the rod bearing on it was super notchy, so not wanting to take any chances, I sent it back, and bought a new OEM crank.  The new one was buttery smooth.

 

I also managed to drop a wrist pin.  I put it a ziploc baggie, and it fell right through the ziploc and straight on the floor - about 2 feet..  I didn't spot any scratches, but I'll look more closely.  Does that mean I'm buying a new wrist pin now too?

 

Pics attached - finished block, wrist pin on removal, and piston (rings & skirt).

 

EDIT.  Got all 4 pistons out.  Stupid screw.  I even have a Reed Prince screwdriver, but it was useless.  I really need a JIS or reed prince impact drill bit...  All the pistons and connecting rods are all in similiar condition (wear on the coating, no in/out play, smooth up/down movement, some front/back play)

Edited December 19, 2017 by jamesm113