Subaru H6 - EZ30

[vristang]

This is the engine in my Subaru Outback 3.0.

The car isn't anything too special... just a standard wagon, leather interior, heated seats, etc...
It does have a 6 cylinder engine, which I'm finding is a little less common... and even less common that folks modify it in n/a form.

The head gasket blew out, so I pulled the engine to R&R.
Since the heads are off, I figured I would consider some grinding... question is... where do I grind?

I've been told by a local shop that the usable limit on milling the heads is .010" to .015".
No idea if that is accurate or not... just what I was told by the ONLY local shop that would discuss technical details with me, instead of telling me to call another shop.


Here are some measurements I did today...
Head Gasket is .025" thick
Quench Pads are .045" below the head gasket surface
Pistons are roughly .011" below the block deck

This means I have roughly .081" quench height.
This seems astronomical to me


I also checked piston thickness and Head surface thickness.
Head looks to be about .300" thick in most of the thin places.
The piston looks to be .300" in the thinnest location.

I'm thinking it would be just fine to fly-cut/clearance the piston up to .050"

I'm attaching pics of the heads as they sit now...

[vristang]

So... I'm not doing anything with the Quench Height.  Mess with that, and you need to correct valve timing, as well as valve clearance.
Since I'm not sure I'll keep the car past a year after this job, that isn't worth the expense...

However, I will eliminate the PCV, and install a vent from each valve cover to a catch can on the passenger firewall.
The catch can is on delivery from Summitt, and should be here tomorrow, I hope...


Here are a few pics of the progress...

1. New Aft cover and all bolts/o-rings behind it
2. Timing Chain and tensioners installed
3. All 58 of the timing cover bolts have been torqued
4. PCV replaced by plug in valve cover
5. Left head vent merging with right head and venting to separator
6. I suspect this cover plate is the source of my 'rattle' under load...
7. These covers went over the fuel rails, and weigh about 10Lbs... they won't be re-installed.