45 replies to this topic

[2X2KOB]

Is the phase-2 SOHC 2.5l engine in my 2000 Outback an interference or non-interference engine?

Has anyone ever experienced a broken timing belt with one of these cars and lived to tell the tale?

[edrach]

Interference.

Is the phase-2 SOHC 2.5l engine in my 2000 Outback an interference or non-interference engine?

Has anyone ever experienced a broken timing belt with one of these cars and lived to tell the tale?

[grossgary]

friend of mine repaired one that broke a timing belt. said it wasn't that bad, had to replace a valve or two but otherwise no other damage.

even the dealer said they've fixed them before with broken belts (Hanover, PA Subaru dealer). i trust my friend more than random conversation with a guy i don't know, but he said he has done it before and hadn't seen too many with block damage.

but with any interference motor the possibilities are endless. give more details and we may be able to help more.

[ferret]

FYI, This comes up alot:

ALL 2.5L ARE Interference, doesn't matter if it's a DOHC or SOHC

ALL 4 Cyl DOHC ARE Interference

ALL 4 Cyl 97 and newer are interference. This was the year the 2.2 went to Solid Lifers.

Which makes it a fact, ALL US Spec Subaru 4 cyl 97 or newer are interference engines.

[grossgary]

FYI, This comes up alot:

ALL 2.5L ARE Interference, doesn't matter if it's a DOHC or SOHC

ALL 4 Cyl DOHC ARE Interference

ALL 4 Cyl 97 and newer are interference. This was the year the 2.2 went to Solid Lifers.

Which makes it a fact, ALL US Spec Subaru 4 cyl 97 or newer are interference engines.

you're shouting?

[ferret]

Reason for the SHOUTING.......recommended maintenance on the timing belt should NOT be ignored. I am not aware of any motors today with a timing belt that are not interference. So take the scheduled maintenance seriously. Your vehicle, your money.

Like an old commercial, "pay me now, or pay me later".

[2X2KOB]

Thanks - I thought it was interference too, then I saw this reference:

http://www.toad.net/...outbackfaq.html

that said otherwise. It's all the way to the end of the file.

[grossgary]

Reason for the SHOUTING.......recommended maintenance on the timing belt should NOT be ignored.

agreed. timing belts can break otherwise as well. failed water pumps or pulleys ruin even new belts on occassion. that's why i replace it all.

[moab austin]

so what about a 95 2,2 imprezza? I was led to belive its a non interference?

[ferret]

95 2.2L in any US Spec Subaru is non-interference.

[edrach]

It is non-interference; EJ22 engines were non-interference up to and including 1996 model years. Note I said model year and not manufacture date.

so what about a 95 2,2 imprezza? I was led to belive its a non interference?

[jjou812]

93 impreza 1.8L interference?

[grossgary]

93 impreza 1.8L interference?

non interference.

[johnceggleston]

on a side note..... i heard that the valves don't collide with the pistons in a subaru interference engine (atleast the dohc). but that the valves collide with the valves and some bend. therefore they can be repaired. any truth to this rumor.

i guess we should schedule our timing belt failure to coinside with our head gasket failures.

john

non interference.

[grossgary]

the valve only go up and down so if they collide they collide, if they don't they don't. can't imagine the t-belt changing that, but i could be wrong. the ports can't overlap, so someone explain if that's true. i've worked on 2.5's and 2.2's, but never DOHC.

in the interference motors you'll have piston to valve contact. level of damage will vary.

[ferret]

John, the 2.5L DOHC is all interference....valve to valve..and piston to valve. Belt Maintenance on any interference engine can be catastrophic if the belt snaps at high rpm's. Doesn't matter what the valve hits, another valve or piston, the cylinder looks like a grenade went off inside, and the motor is trash.
I have read a few who broke at low RPM, and got away with only a belt replacement, but the 2 I saw, and Emily from CCR can attest to, they do severe damage at speed.

[grossgary]

valves will hit valves....after the piston smashes them sideways!

[johnceggleston]

my understanding was that the valve stems were angled away from each other, riding on 2 different cam shafts. as a result, the valve bodyies were overlaping if both were extended. i feel like ive seen a picture of a piston with cutouts (half moon shaped) for piston valve clearence.

but i don't open engines and work on them. i does not surprise me that a failed timing belt would detsroy an engine.

the valve only go up and down so if they collide they collide, if they don't they don't. can't imagine the t-belt changing that, but i could be wrong. the ports can't overlap, so someone explain if that's true. i've worked on 2.5's and 2.2's, but never DOHC.

in the interference motors you'll have piston to valve contact. level of damage will vary.

[eventoday]

i barely lived to tell the tale.
one of my pulleys blew into pieces.
13 of 16 valves were destroyed.
it has been one long nightmere so iwould recomend changing tensioners and pulleys

[grossgary]

my understanding was that the valve stems were angled away from each other,

that's definitely interesting.

in any event, a friend of mine that owns his own business fixed one last year that threw a belt. said it wasn't that bad at all. needed one or two valves and the pistons and cylinder walls were fine. probably a slow speed break i guess.

[nipper]

Is the phase-2 SOHC 2.5l engine in my 2000 Outback an interference or non-interference engine?

Has anyone ever experienced a broken timing belt with one of these cars and lived to tell the tale?

95% of the time, its just a bent valve or two that have to be replaced, but that still adds a huge repair bill. Its important that if you get a flashing CEL that the car be checked out . One of the causes for a flashing CEL is the cam and crank postions sensors being slightly out of synch ... caused by a timing belt with some play in it.
Timing belts need to be changed before thier service interval. Rarely in the last 15 years do youhear of one breaking with no other cause that was properly maintained.

nipper

[AWDCar]

So is it fair to say that if a timing belt goes on a pre-97 motor (non-interference) it will NOT do any damage to the motor?

[grossgary]

So is it fair to say that if a timing belt goes on a pre-97 motor (non-interference) it will NOT do any damage to the motor?

your question is loaded. Yes. And no. you already answered the question yourself by including the disclaimer "non-interference". If a timing belt breaks on a non-inteference engine then there will not be any internal engine damage regardless of year, make or model.

but you said "pre-1997", not all pre-1997 subaru's were non interference. i think the 1996 2.5 liter motors were interference as well as the subaru SVX EG33. the 2.2 liter pre 1997 engines are all non-interference engines. a generic statement might be, "all non-SVX (EG33) 1995 and earlier subaru's are non-interference".

[Wayne Boncyk]

You are indeed correct. The 1996 2.5L DOHC engines are "interference," in the sense that both intake and exhause valves cannot be open simultaneously. They hit each other in that mode, with nasty consequences. Still, if my memory hasn't completely failed me, there is enough clearance in that DOHC design so the valves don't actually contact a TDC piston when they're open. Bottom line - there are different flavors of "interference."

[DerFahrer]

Okay, here's the scoop.

Any EA-series engine is non-interference.

ANY and ALL DOHC Subarus are valve-valve interference. Yes this is properly called 'interference' because as has been explained in previous posts, serious damage can result that requires the engine to be torn down.

NOW, the SVX EG33 is technically valve-valve interference since it is a DOHC engine, but the EG33 was the only Subaru engine to have one cam gear-driven off the other. So unless your cams got out of sync with each other, which is a HIGHLY-unlikely scenario, it is basically a non-interference engine.

As best I know (so I could be wrong), but all 97-up NONTURBO Subaru engines (besides the SVX EG33) are piston-valve interference. This includes the EJ22EZ (Phase II), EJ25 (all versions including EJ25D, EJ251, and EJ253), and the EZ30D. The EJ205, EJ255, and EJ257 are all turbo motors, therefore they have different-shaped pistons in the interest of lower CR's that might not interfere with the valves. But I cannot CONFIRM this.