Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

Interference or non?


  • Please log in to reply
45 replies to this topic

#1 2X2KOB

2X2KOB

    Subaru Fanatic!

  • Members
  • 393 posts
  • Midstate MO

Posted 03 February 2006 - 08:46 AM

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?

#2 edrach

edrach

    RIP 6/28/14

  • Members
  • 12,326 posts
  • Bothell, WA

Posted 03 February 2006 - 08:50 AM

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?



#3 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 20,094 posts
  • WV

Posted 03 February 2006 - 09:35 AM

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.

#4 ferret

ferret

    Subaru Nut

  • Members
  • 669 posts
  • Northern NJ

Posted 03 February 2006 - 09:36 AM

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.

#5 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 20,094 posts
  • WV

Posted 03 February 2006 - 09:47 AM

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?

#6 ferret

ferret

    Subaru Nut

  • Members
  • 669 posts
  • Northern NJ

Posted 03 February 2006 - 10:08 AM

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".

#7 2X2KOB

2X2KOB

    Subaru Fanatic!

  • Members
  • 393 posts
  • Midstate MO

Posted 03 February 2006 - 10:14 AM

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.

#8 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 20,094 posts
  • WV

Posted 03 February 2006 - 10:35 AM

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.

#9 moab austin

moab austin

    New User

  • Members
  • Pip
  • 6 posts
  • moab

Posted 04 February 2006 - 06:18 AM

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

#10 ferret

ferret

    Subaru Nut

  • Members
  • 669 posts
  • Northern NJ

Posted 04 February 2006 - 06:58 AM

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

#11 edrach

edrach

    RIP 6/28/14

  • Members
  • 12,326 posts
  • Bothell, WA

Posted 04 February 2006 - 11:22 AM

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?



#12 jjou812

jjou812

    USMB Regular

  • Members
  • PipPipPip
  • 69 posts
  • York County, PA

Posted 14 March 2006 - 01:50 PM

93 impreza 1.8L interference?

#13 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 20,094 posts
  • WV

Posted 14 March 2006 - 01:54 PM

93 impreza 1.8L interference?


non interference.

#14 johnceggleston

johnceggleston

    Lite Master of the Subaru

  • Gold Subscribers
  • 6,403 posts
  • Virginia

Posted 14 March 2006 - 02:05 PM

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.



#15 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 20,094 posts
  • WV

Posted 14 March 2006 - 02:24 PM

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.

#16 ferret

ferret

    Subaru Nut

  • Members
  • 669 posts
  • Northern NJ

Posted 14 March 2006 - 02:26 PM

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.

#17 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 20,094 posts
  • WV

Posted 14 March 2006 - 02:37 PM

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

#18 johnceggleston

johnceggleston

    Lite Master of the Subaru

  • Gold Subscribers
  • 6,403 posts
  • Virginia

Posted 14 March 2006 - 02:42 PM

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.



#19 eventoday

eventoday

    USMB is life!

  • Members
  • 125 posts
  • denver

Posted 14 March 2006 - 03:31 PM

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

#20 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 20,094 posts
  • WV

Posted 14 March 2006 - 03:34 PM

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.

#21 nipper

nipper

    Semi Elite Master of the

  • Members
  • 17,637 posts
  • Long Island NY

Posted 15 March 2006 - 12:14 AM

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

#22 AWDCar

AWDCar

    New User

  • Members
  • Pip
  • 7 posts
  • Ottawa, Canada

Posted 01 May 2006 - 10:20 AM

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?

#23 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 20,094 posts
  • WV

Posted 01 May 2006 - 10:25 AM

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".

#24 Wayne Boncyk

Wayne Boncyk

    Subaru Fanatic!

  • Members
  • 354 posts
  • Denver

Posted 01 May 2006 - 11:27 AM

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."

#25 DerFahrer

DerFahrer

    Formerly subyluvr2212

  • Members
  • 2,417 posts
  • Orlando, FL

Posted 01 May 2006 - 08:09 PM

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.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users