2004 Forester XT: engine details

[herbob]

Questions on Forester XT engine:

 

1) Hydraulic or mechanical lifters? If mechanical, is adjustment with shims or screws?

 

2) Is it an inerferential engine?

 

3) It's a 2.5liter DOHC. Hmmm. . .sounds reminiscent of my 97 Outback 2.5 DOHC with the infamous "non-headgaskets." The improvement after the 97 Outback was supposedly better head gaskets associated with the 2.5 SOHC. At any rate, any concern with head gaskets in the Forester XT? (I assume if it's the 97 Outback motor, then they wouold need to replace the head gaskets after each test drive. . . .)

 

Thanks for any inputs!

[DerFahrer]

The Forester XT, Baja Turbo, the STi and the new 2005 Legacy 2.5GT modeals all share the same block and heads, the STi and Legacy 2.5GT will have more horsepower because of different exhaust and IC setups.

 

If these engine's heads are similar to the current Phase II EJ25 engines in all other Subarus, they will have solid lifters, unsure of the adjustment procedures though.

 

All DOHC Subaru engines are valve-valve interference. To the best of my knowledge, no piston will ever strike a valve, but the valves will strike each other in the event of a timing belt failure.

 

I doubt that the headgaskets will be too problematic on the new turbo engines. Since the indestructible Legacy Turbo engine came out, Subaru has not half-assed their turbo engines. With proper maintenance and a knowledgeable driver, these engines should be in it for the long haul.

[Guest lothar34]

Valve-valve interference? If it's DOHC, then there's one belt driving both cams, right? So if something happened to the belt, the cams (and valves) would stop, right? And not hit each other? Or is there something that would make one cam stop and not the other?

 

I thought interference was only something to worry about since the crank keeps turning when the cams stop.

[1 Lucky Texan]

In theory, the valve springs should want to close the valves, moving them away from each other. But I guess in the real world ,some combination of the belt stretching, skipping, breaking, shearing off teeth, PLUS inertia could cause valve clash. I recall Emily at CCRengines saying they have seen engines with piston/valve clash. I don't recall if she said which engines do this.

[ferret]

herbob, Check out the Edmund's Forester board:

http://townhall-talk.edmunds.com/WebX?14@109.gQszbOq3etK.3@.ee94fe5

There are quite a few Forester XT owners/fanatic's there. I feel sure they can answer you questions.

As far as Interference, this has been discussed here at length.

ALL 2.5's ARE INTERFERENCE ENGINES. This is included in a letter I rec'd from Subaru about an inquiry. The SOHC has the valves at a lower angle than the previous 2.2, so there is 'negative' clearance on full compression and valve opening. In plain english, valve open piston coming up, SMASH.

DOHC have the same engineering as well as each cam being independently driven from the cam belt. So for example the intake is open (extended) and the exhaust opens fully, it WILL hit the intake and one or both will be damaged as well as the valve guides and head itself depending on the force applied.

[herbob]

Thanks for all the inputs, everyone!

[wrxsubaru]

Originally posted by subyluvr2212

The Forester XT, Baja Turbo, the STi and the new 2005 Legacy 2.5GT modeals all share the same block and heads, the STi and Legacy 2.5GT will have more horsepower because of different exhaust and IC setups.

 

 

I heard Subaru dramticly under rated the forester/ baja turbo. People have dynoed the forester turbo and have put out around 230 WHP, only about 20 less than the STI!!! I think the new legacy turbo will have a more correct power rating than the forester/baja turbo, so maybe it wont have any more power.