H6 3.0 valve adjustment

[CNY_Dave]

Has anyone ever actually had the valves adjusted on their H63.0?

 

Were they in our out of spec?

 

Do they get loose or tight?

 

Dave

[Danbob99]

The H6 Valve adjustment is due per subaru at 105K for an inspection. They are shim over bucket lifters and use a different size shim than all the 2.5 motors. They are the same size has WRX valve shims.

 

The valves tend to wear tighter and when adjusted I try to leave them on the loose end of the adjustment spec. (to allow for future wear, and overtight valves cause misfires, where as a loosely adjusted valve does not.)

 

Most times the valve adjustment is still within spec at the 105K mark. In my experience most are still withing spec past the 120K point as well.

 

Dan

[GeneralDisorder]

If you don't adjust them they will get tighter just like the DOHC H4's and you'll burn an exhaust valve when the clearance closes to zero. Seriously - don't ignore that service. I just did an EJ25D with a burned valve at 170k due to a lack of proper valve adjustment.

 

GD

[CNY_Dave]

I was in the dealers at 130K or so (10+k ago) and they did not feel checking the valves was high priority.

 

Have had the car from 55k.

 

Dave

[CNY_Dave]

The H6 Valve adjustment is due per subaru at 105K for an inspection. They are shim over bucket lifters and use a different size shim than all the 2.5 motors. They are the same size has WRX valve shims.

 

The valves tend to wear tighter and when adjusted I try to leave them on the loose end of the adjustment spec. (to allow for future wear, and overtight valves cause misfires, where as a loosely adjusted valve does not.)

 

Most times the valve adjustment is still within spec at the 105K mark. In my experience most are still withing spec past the 120K point as well.

 

Dan

 

Tighter- via stem elongation, the valve 'fluting', or seat recession?

 

 

Dave

[idosubaru]

Tighter- via stem elongation, the valve 'fluting', or seat recession?

 

 

Dave

have you seen GD's thread on burnt exhaust valves, that's a good discussion on the topic he just started recently.

[GeneralDisorder]

Every engine seems to be a little different - thus why Subaru says to check them at 105k. Sometimes you get an exhaust valve that wears quicker than the other's. I've seen it on 2.2's and 2.5's - H6's are less common but the design is the same on the bucket/shim valve system and the valves themselves aren't any different in design.

 

Checking them is simple (once you remove the valve covers - which is a messy job being the H6 is so tight) - adjusting them is the hard part.

 

The wear is on both the seat and the valve face. The stems don't stretch or anything like that. But they get tight and checking them is a LOT cheaper than dealing with a burned valve let me tell you - if you have to have a set of those heads rebuilt..... easily $600 for the machine work alone.

 

GD