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Midwst

2.2L interferance debate: answer

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I finally found an official answer regarding the 2.2L subaru engines. It is true that up till 1996 they were non-interferance. Starting in 1997, all subaru engines are interferance: both 2.2 and 2.5.

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<<Starting in 1997, all subaru engines are interferance>>

 

exept for the EG33

 

Did the SVX even survive that long? and he did say that he was talking about 2.2 and 2.5. He said nothing about 3.3L engines. . .

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Hang on a second people.

 

The EG33 is technically an interference engine, like all DOHC Subarus. But the EG33 is the only Subaru motor that had one cam gear-driven off the other. So the gear teeth would have to shear off or somehow skip, but in that .001%-chance of that happening, you would have engine damage.

 

Just had to point that out :D

 

I coulda told you that though Midwst. I have the EndWrench article saying that.

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Here's another wrinkle. I bought a '97 Impreza for my wife about 3 months ago and it had 110K on the odometer (carfax info seems to indicate that mileage is legitimate) so I'm pretty sure the engine is original. It is definitely a non-interference engine. VIN plate indicates that the manufacture date is 12/96. Lucky me since I did not want an interference engine in our garage.

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Hey Ed, it's the model year not the actual year that would determine if it's an interferance engine or not and the 97 model year began in Sept or Oct of 96. Also if it has Single port exhaust head then it's an interferance engine.

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Two questions spring to mind.

 

1. Would knowing whether a specific Subaru engine is, or is-not interference, be considered valuable or important information to the owner of a Subaru vehicle?

 

2. Does Subaru consider this to be valuable or important information?

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It's important in that you can wait until the timing belt breaks with a non-interference head since there is little likelihood that you will damage the engine. With an interference engine breaking the timing belt will likely cost you a valve job and possibly a few pistons. The difference in cost between a major engine overhaul as opposed to what is essentially routine service.

 

I wanted to know which since I bought my car used and I have no idea when the timing belt was last replaced. Knowing that it's non-interference means I can wait awhile before doing the belts....even wait until a belt lets go if I should choose to do so.

 

Lastly, the rational for going to an interference head was to squeeze a few more horsepower out of the engine. I prefer reliability as opposed to more power.

 

Two questions spring to mind.

 

1. Would knowing whether a specific Subaru engine is, or is-not interference, be considered valuable or important information to the owner of a Subaru vehicle?

 

2. Does Subaru consider this to be valuable or important information?

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My understanding (taken a previous post on this question) is that the non-interference engine has the sparkplug coming out of the cylinder at a 45 degree upward angle; the interference engine has the 'plugs coming out of the top of the cylinder head horizontally to the ground (through the valve cover). I've never seen the later version 2.2 so I'm going by what I've read here on the Board. I would imagine the engine serial number would tell you the same information but that would be buried somewhere in Subaru's database. Someone please correct me if you have better information. With 113K on the car now, it would be smart to do the belt now if it is indeed an interference head.

How do you know it's DEFINITELY non-interference Ed? Did you buy it with a broken timing belt or something?

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Edrach, I agree totally with your logic about NON-interference engines (which is why I love my '95 Legacy.)

 

But I have a question re your '97 Impreza: Based on the assumption that Subaru changed the 2.2L to an interference design in l997, how can you be sure "It is definitely a non-interference engine?" Is there some way to visually inspect? Did Subaru retain the "original" EJ22 in Imprezas longer than they did in Legacies?

 

My fear (and I hope I'm wrong for your sake) is that '97 model year vehicles started manufacture in the last half of 1996, thus your car would be the "new", i.e. interference, design.

 

Any insights you have would be appreciated.

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My understanding (taken a previous post on this question) is that the non-interference engine has the sparkplug coming out of the cylinder at a 45 degree upward angle; the interference engine has the 'plugs coming out of the top of the cylinder head horizontally to the ground (through the valve cover)...

For the novice/casual reader:

 

Edrach's description does not DEFINE the reason why any given generic engine is interference or not, he is just using sparkplug location as a "marker" or "landmark" for telling which Subaru EJ22 casting was used on its interference engine.

 

Identifier, not reason.

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And that identifier came from my question the last time someone posted a thread about the interference version of the 2.2L; I'll try to find the post if I can.

For the novice/casual reader:

 

Edrach's description does not DEFINE the reason why any given generic engine is interference or not, he is just using sparkplug location as a "marker" or "landmark" for telling which Subaru EJ22 casting was used on its interference engine.

 

Identifier, not reason.

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Alright then, I'll answer my own somewhat rhetorical line of questioning.

 

1. Would knowing whether a specific Subaru engine is, or is-not interference, be considered valuable or important information to the owner of a Subaru vehicle?

Obviously yes.

 

2. Does Subaru consider this to be valuable or important information?

Well, either Subaru doesn't think it's important info, or they just don't think the purchasers of their vehicles are worthy of having a source of OFFICIAL data on the matter.

 

I'm sick and tired of the constant re-hash, speculation on this matter. It's time that Subaru steps-up to the plate.

 

I had the parts department at my local dealer chide me for my preventative replacement of the valve-gear on my '00 2.2 telling me that it's not an interference design, so in essence, I had "nothing to worry about".

 

FOR CHRIST SAKE SUBARU, GET YOUR HEADS OUT OF YOUR ASSES ...YOUR DEALERS DON'T EVEN HAVE DATA ON THIS MATTER.

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I just searched for that thread and I can't find it now. However, there are a TON of posts when you search "interference" or "non-interference." So that begs the question.....IS THERE ANY WAY TO VISUALLY TELL WITHOUT TAKING APART ANYTHING ON THE ENGINE WHETHER THE 2.2L IS INTERFERENCE?

And that identifier came from my question the last time someone posted a thread about the interference version of the 2.2L; I'll try to find the post if I can.

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Alright then, I'll answer my own somewhat rhetorical line of questioning.

 

 

Obviously yes.

 

 

Well, either Subaru doesn't think it's important info, or they just don't think the purchasers of their vehicles are worthy of having a source of OFFICIAL data on the matter...

Yes, it is important to we enthusiast who are interested in the mechanical aspects of our vehicles. However, it is arguably unimportant to the great unknowing masses to whom Subaru (or any car maker) wants to sell its products. If it were important to said masses, we wouldn't keep buying vehicles that use a valve drive system that regularly fails and risks engine destruction.

 

Look at the state of car commercials today; what are they selling? Flash, sex-appeal, "safety" and/or transportation. What is under the hood is unimportant; what those big alloy wheels are attached to is unimportant. It is an appliance, and as long as the appliance does its job we should not be concerned with how it does it or what happens when it no longer does. Just take it to the appliance repair shop, or buy a new appliance.

 

The above is not meant to be a "conspiracy theory", just the practical corporate view of things.

 

I have a novel idea: Could the Subaru West folk that were at WCSS7 be convinced to shine some light on this? They KNOW that we are "the choir", and that we will not go buy Hyundais if we know "The Truth". :lol:

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It is impossible for the spark plugs to go straight through the top of the cylinder head on ANY EJ22 except the 22B.

 

The reason for this is that there's a cam in the way :)

 

The DOHC engines have the spark plugs going straight through the heads, right in between the two cams.

 

I THINK (I don't know for sure, but I THINK) that the 97-up EJ22's have the spark plugs sitting on the top sides of the heads, but they are going through the upper part of the valve covers. The old EJ22's have them just above the valve covers.

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I picked up my 97 2.2 in Nov. of 1996 and it had the interference engine. I found this out by letting the idle pully come apart on me at 288,000 miles. ( Dont forget to check the pullys when changing belts) I am sure most of you know but for the ones that dont the piston was coned up in the center of the 1997 which took away the space that was used to keep the pistons and valves apart. This was done to get a little more power. I agree with edrach, I would rather have the reliabilty then the extra power.

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I took a photo of my '97 Impreza as well as my '91 Legacy and I can't really tell any difference from where the sparkplugs protrude. Photos can be seen at http://www.ultimatesubaru.org/photos/showgallery.php?cat=735 in my photo gallery. When I get my son over here, I'll photograph his '96 EJ22 for comparison. I did look at the serial numbers on both engines and I'm beginning to draw the conclusion that I have an interference engine. Prior to the s/n is a "CC" on our legacy engine; prior to the s/n on our Impreza is a "BB". Oddly enough our Impreza engine's s/n is 22222! Anyone else want to play s/n poker?:cool:

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Tried to do more research on this . . . alas, to little avail! Searched under "EJ22 History" and found a great "Technical Reference Booklet" that feret provided back in June and Legacy777 made available for download on his site--a wonderful resource for Subie lovers, really good pix and graphics, organized chronologically, very thorough.

 

Except for the one thing anyone would want to know: How to identify the engine!

 

On page 29 it states what most of us know--the 2.2L was "enhanced" in 1997 and that "this eliminates the clearance that was available between the piston at TDC and a fully opened valve." Compression ratio had been increased from 9.5:1 to 9.7:1 in 1996.

 

But they still called it a "2.2L Phase 1" engine, same designation as the original EJ22s. "Phase 2" didn't arrive 'til 1999 along with a boost to 10:1 compression ratio.

 

The sixth character in the s/n identifies the engine type, a "6" indicates the 2.2L.

 

Edrach, does your '97 have a "6" as the sixth character? I really think you may be onto something with your CC vs. BB observation. But there's absolutely no mention of it in the booklet.

 

So I guess my question becomes . . . why the heck wouldn't Subaru provide such basic valuable information to people who need to know?!!

 

Sorry for the long ramble. Good luck, edrach. I assume you're going to be changing the Impreza's timing belt soon!

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Tried to do more research on this . . . alas, to little avail! Searched under "EJ22 History" and found a great "Technical Reference Booklet" that feret provided back in June and Legacy777 made available for download on his site--a wonderful resource for Subie lovers, really good pix and graphics, organized chronologically, very thorough.

 

Except for the one thing anyone would want to know: How to identify the engine!

 

On page 29 it states what most of us know--the 2.2L was "enhanced" in 1997 and that "this eliminates the clearance that was available between the piston at TDC and a fully opened valve." Compression ratio had been increased from 9.5:1 to 9.7:1 in 1996.

 

But they still called it a "2.2L Phase 1" engine, same designation as the original EJ22s. "Phase 2" didn't arrive 'til 1999 along with a boost to 10:1 compression ratio.

 

The sixth character in the s/n identifies the engine type, a "6" indicates the 2.2L.

 

Edrach, does your '97 have a "6" as the sixth character? I really think you may be onto something with your CC vs. BB observation. But there's absolutely no mention of it in the booklet.

 

So I guess my question becomes . . . why the heck wouldn't Subaru provide such basic valuable information to people who need to know?!!

 

Sorry for the long ramble. Good luck, edrach. I assume you're going to be changing the Impreza's timing belt soon!

 

No, my s/n on the Imp is 22222. Try doing your search under "interference" or "non-interference." I got lots of stuff to look at yesterday but didn't find what I wanted. I did send a note off to Smart Service and I'll see what they tell me; I'd trust them before any dealer in the country. Also, there's more digits (letters?) before the "BB" and "CC" on both my engines but I can't tell what it is. I re-checked the s/n on my '91 Legacy and it's 76 CC 22112. I'll recheck the Imp again when my wife comes home. And yes, I suspect I'll be re-doing the timing belt soon.

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I rechecked the s/n on our '97 Imp and it's 65 BB 22222. I checked the s/n on my son's '96 Imp and it's 15 AB 11111. Now I'm really puzzled. What are the chances of 5 of kind on one car, much less two?

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I received the following answer from Smart Service:

 

1997 was the model year that the 2.2 engine went to short skirt pistons and roller rockers. The only way I know to identify them is looking at the rocker arms or pistons. The engine, including spark plug holes, looks identical to the predecessor.

 

Thanks Mike, I appreciate the clarification.

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