Used Subaru Legacy, SOHC or DOHC?

[jana519]

I'm looking to buy a secondhand Legacy for my next vehicle, and the biggest engine differences are SOHC vs DOHC. My first choice is DOHC for higher HP, but I've been reading user boards and some say the DOHC are more "problematic"? Is there any truth to this, are SOHC engines inherently more or less reliable?

If you run two brand new engine for 250K miles with all regular scheduled maintenance, is the SOHC going to have less issues? Let's unpack this idea a little bit. SOHC engines should, in theory, have simpler layouts and therefore better ease of access and easier to maintain. But it shouldn't be inherently less temperamental than DOHC with factory tune. Am I correct? My thinking is DOHC engines being problematic or temperamental is as a result of user error - not design.

Open to discuss.

 

[NutBucket]

What era are we talking here? In the mid-late 2000's, the NA motor is SOHC and the turbo motor is DOHC. And late 90's to early 2000's the SOHC motors were notorious for headgasket problems.

Basically, there's a lot more to engine reliability than SOHC vs. DOHC. One isn't better than the other from that standpoint.

 

[T2urtle]

What era are we talking here? In the mid-late 2000's, the NA motor is SOHC and the turbo motor is DOHC. And late 90's to early 2000's the SOHC motors were notorious for headgasket problems.

Basically, there's a lot more to engine reliability than SOHC vs. DOHC. One isn't better than the other from that standpoint.

I thought the 90s were DOHC blew head gaskets like a 2.5 but u wanted to get a SOHC like a 2.2.

Sent from my SM-N910T using Tapatalk

 

[NutBucket]

I'm probably confused. At any rate, my point is one isn't inherently better than the other.

 

[T2urtle]

Either way to me..... once they fix the head gasket with the right ones. The problem is over.

Least that was my research, I want a subaru wagon as my winter beater. Late 90s- mid 00.

Also some model subaru have bad wheel bearings. They just keep going out, bad hub design.

Overall they still are low maintenance cars. That only need the basic work.

Sent from my SM-N910T using Tapatalk

 

[jana519]

What era are we talking here? In the mid-late 2000's, the NA motor is SOHC and the turbo motor is DOHC. And late 90's to early 2000's the SOHC motors were notorious for headgasket problems.

Basically, there's a lot more to engine reliability than SOHC vs. DOHC. One isn't better than the other from that standpoint.

Right. I'm planning to pick up a "mechanics special" for a song, pull the engine, and rebuild it entirely. So basically, I'm looking at first gen Legacies from 89-93. Busted 1st gens routinely sell for $400-500 here in CO.

That narrows my choices down to the 2.0L DOHC or the 2.2L SOHC. The 1.8L SOHC and 2.0L SOHC are underpowered at 108HP and 124HP, respectively. I want to avoid those entirely.

 

[jana519]

T2urtle, thanks. According to Wikipedia, it was the 2.5L engines introduced in 1996 that had the shite head gaskets. Apparently, the increase of displacement required greater cooling than was anticipated. Quote:

"The EJ251 commonly experienced head gasket failures resulting in interior channel breaches or exterior fluid leaks due to the continued use of a single layer coated gasket first introduced on the EJ25D."

This issue was fixed with the 99 model years.

 

[NutBucket]

In that case, I'd look for the car with the least rust/best cosmetics.

 

[jana519]

Yep, so important to check for a straight body and no rust. Will be doing that, for sure.

I think I've basically got it narrowed down to the EJ20D 2.0L DOHC. The small sticking point is that servicing the plugs is supposedly harder than on the SOHC, but using NGK Platinum plugs so it's an 80,000 mile job should be a fine solution.

 

[NutBucket]

Dude, for that kind of beater who cares. It's really no big deal.

 

[jana519]

Yeah, guess you are right.

 

[T2urtle]

Yep, so important to check for a straight body and no rust. Will be doing that, for sure.

I think I've basically got it narrowed down to the EJ20D 2.0L DOHC. The small sticking point is that servicing the plugs is supposedly harder than on the SOHC, but using NGK Platinum plugs so it's an 80,000 mile job should be a fine solution.

Plugs on any subaru is harder then it should be. It's just part of the being a subaru owner. U need very tiny hands or have children do it for u.

I don't know much on early 90s. They don't appeal to me much. A 96 outback sport, I can dig that. Or the oh so popular 2.5rs of like 99-01.

Sent from my SM-N910T using Tapatalk

 

[Demo24]

Right. I'm planning to pick up a "mechanics special" for a song, pull the engine, and rebuild it entirely. So basically, I'm looking at first gen Legacies from 89-93. Busted 1st gens routinely sell for $400-500 here in CO.

That narrows my choices down to the 2.0L DOHC or the 2.2L SOHC. The 1.8L SOHC and 2.0L SOHC are underpowered at 108HP and 124HP, respectively. I want to avoid those entirely.

The 2.2 is also quite underpowered at around 140hp. However, it was quite stout (closed deck) and I don't believe ever experienced significant head gasket issues. I had one in my 95 legacy with the 4eat. Surprisingly large inside and it all worked well enough. It was however damn slow past 10mph, and as such gas mileage was....poor for that size vehicle. I still seem them all over the high country, so I guess they are holding up well enough.

 

[jana519]

The 2.2 is also quite underpowered at around 140hp. However, it was quite stout (closed deck) and I don't believe ever experienced significant head gasket issues. I had one in my 95 legacy with the 4eat. Surprisingly large inside and it all worked well enough. It was however damn slow past 10mph, and as such gas mileage was....poor for that size vehicle. I still seem them all over the high country, so I guess they are holding up well enough.

Yes, I'm doing some reading and seems the 2.2L EJ22E SOHC has the reputation for being "bulletproof." They say it can even handle 10 PSi boost stock. I wouldn't slap a turbocharger on a high mileage EJ22E though, that would be short-sighted. Still, it's a pretty sweet engine.

Surprised to hear you say that, there are a lot of people driving used 2.2L NA Legacies here in CO, it's a popular car. I'm just looking at numbers on paper, I guess I need to do some test driving out here and see how it really drives in person.

 

[NutBucket]

His problem is he expects a mid 90's sedan to be fast....at high altitude with no turbo/supercharger. I had a rental 2012 Legacy in Co. Springs a few years ago and it felt plenty slow too.

 

[jana519]

I've been getting a s*** ton of info on this, beyond the original scope of the thread... There's two options I'm now considering. One would be buy a 1st gen 2.2L NA Legacy for $300-400, pull the block, modify it, and add a turbocharger for mild boost. Other option is buy a 2nd gen 2.5L Legacy for $1100-1300, and add 2.2L heads - this is more displacement and higher compression. TBH, I'm not sure how much power either option would make.

Since I am taking the time and effort to pull the engine and rebuild it, I want to build the engine somewhat. Putting it back in as bone stock would be considerable effort for what amounts to little gain.

 

[NutBucket]

Why not just buy a complete ej20 turbo?

 

[jana519]

Why not just buy a complete ej20 turbo?

Don't have the budget for it. I am going to recycle the previous engine to keep the costs down. My budget is like $1600 for donor car, new engine parts, and machine shop work.

Realistically, the only way I keep costs down is do all the labor and assembly myself, use the previous engine as a donor, and do the work piece by piece.

 

[Demo24]

His problem is he expects a mid 90's sedan to be fast....at high altitude with no turbo/supercharger. I had a rental 2012 Legacy in Co. Springs a few years ago and it felt plenty slow too.

Not sure if you're referring to me or op. In my case it was rather slow at sea level as well. Which basically meant averaging 20mpg. The automatic greatly contributed to its general slowness though.

Don't have the budget for it. I am going to recycle the previous engine to keep the costs down. My budget is like $1600 for donor car, new engine parts, and machine shop work.

Realistically, the only way I keep costs down is do all the labor and assembly myself, use the previous engine as a donor, and do the work piece by piece.

Honestly, I'm not really sure why even bother at this rate. Boosting a 2.2 might be ok, but you're doing that to a 20 year old engine. The n/a 2.5 didn't take to boost well from what I've heard in the past (may be confusing it with another one). Finding an ej20 is probably the most cost effective and easiest swap (they do bolt in) for turbo'ing. However, those engines have their own issues with engine bearings, etc (I had one grenade itself in my 05 wrx, didn't feel like taking that chance again)

 

[NutBucket]

Not sure if you're referring to me or op. In my case it was rather slow at sea level as well. Which basically meant averaging 20mpg. The automatic greatly contributed to its general slowness though.

Your expectations were too high My first car was a '91 Accord but a 5-speed. Plenty fast to get in trouble with!

 

[jana519]

Just to clarify... the EJ20 Turbo and it's variants are all JDM (up until 2002 or sth). JDM reseller prices are ridiculous... If I can find a local private seller, well that's entirely different. But who knows how much searching that will take... I will try NASIOC, but don't want to pay shipping.

May just have to drive and pickup.

 

[NutBucket]

Subaru prices are too high still. Maybe look for a wrecked FXT or something.