Project ST-Why: My Love-Hate Relationship with the World's Worst Subaru

In reply to jharry3:

I was planning on that option, but in looking around, the cheapest I could find a complete engine was around $3800. That seemed a little unreasonable, considering the risk factor and relatively high mileage. I am writing this in steps until I get up to present time; I ended up deciding to buy a new loaded shortblock direct from Subaru. Should have a post describing that soon.

In hindsight, I may have held out for a wrecked STI for the complete powertrain.

I loaded up all the cylinder heads and took it to a local shop pretty familiar with Subarus. They seemed to think a good cleaning and polishing would be fine. If the caps were too gouged, we would have to consider line boring the heads and then adjusting the valve clearances appropriately. Or...I could just buy new parts at the cost of around $1000 per bank.

A few days later the shop called and said the heads were good to go. They had polished the cams, cam caps, and anywhere on the head the cams rode. They also replaced the valve stems, checked valve clearances, and swapped buckets as needed. After checking leakage and other specs they deemed the heads fit for service. They looked almost new when I picked them up and they best news was that the total cost was under $200.

Meanwhile, I had this sitting in my garage.

I quickly found the offending cylinder that was knocking. I had to decide whether to split and rebuild the case, or buy new. After researching the costs of new parts and contemplating the risk of rebuilding it myself, I decided to order a new loaded shortblock directly from Subaru. A few days later and for $1800 shipped, this showed up on my doorstep:

I also ordered a new oil pump, sump pan, oil cooler, timing belt kit, and master gasket kit. Notice the oil control solenoids and cam gears are absent from that list. I had a plan!

Watching this thread, because I don't have it in me to go through all of this with another Subaru. Good luck!

The boy racer in me has always wanted one of those.

The rational side of me laughs and then laughs harder knowing the number of STi's around here...

At some point the ID is going to defeat the ego and one will end up in my driveway.

In reply to java230:

Good man! I have several and one identical to this one! Identical as to year, color and knocking engine when I bought it. Mine is seriously low mileage but a hotrodder got ahold of it before me. STi's are great cars and a lot of fun, but they are quirky.

I wonder where in the universe you are? Getting heads reconditioned for $200? Your project caught my eye because I succumbed to a similar deal. 67K miles and very little rust on my silver 2007 STi. The engine supposedly ran but knocked. I grabbed it because I wanted a street toy. I have a full-blown, dedicated '08 track STi with over 400 WHP. I said why not buy it? I had lots of parts in the basement. I ended up needing them! Mine came with a lot of Perrin goodies so I went for a build to net me near 400 WHP, so it could be a durable DD and a backup track day car. I am getting close to assembling the engine. Pistons are getting coated. Block is getting bored. Ported big-valve B25 heads are ready. I rebuild my AVCS sprockets. Do not reuse the oil-water heat exchanger, AKA "oil cooler". It will be loaded with metal, and you should ditch it anyways. There's a cleaner, better option for that area.

What are those sockets called (besides Michigan")? I'm here to help if I can!

In reply to Scargod:

Sounds like an awesome build! I was really tempted to make this a track only car, but want to get more involved with wheel to wheel racing and I don't have the kind of budget to support running an STi. I think the heads were so cheap because not much really needed to be done. I just wanted to peace of mind of having had a machine shop check all the tolerances and verify that it wasn't a mistake to reuse them.

The sockets were from Harbor Freight. Here's a link!

Now that you have a fresh shortblock, you can split the broken one and give us carnage pictures.

So, rather than purchase new AVCS (again, Subaru's brand specific way to say variable valve timing) sprockets and solenoids, I decided to clean them the best as I could. I figured they were fairly easy to access later on and if they threw a code, I could replace them then.

I started with the solenoids. After cleaning them the best I could, I dunked the body in cleaner and manually actuated the solenoid until I could no longer see old oil spurting out. I checked the solution with a magnet and couldn't find any significant evidence of bearing material. (I realize not all layers of the bearing are magnetic, but most of the material I found in the pan was.) I then strained the solution and looked for any particulates; I didn't see anything that worried me.

The cam gears require a special socket to take them apart so I purchased that and gave it a try.

I carefully disassembled each cam gear as the parts inside are impossible to buy. I would need to reuse the large clover shaped O-ring, springs, and plastic retainers. I'm glad I opened them up because look at how much old oil was hiding inside:

I meticulously cleaned each little part and the small oil passageways until no dirty oil remained. It reminded me a lot of cleaning old motorcycle carbs. I checked the rotor and casing for any scoring and didn't see any evidence of damage. I'll admit that I spent way more time cleaning these than it was probably worth, but I had a lot of satisfaction in saving a bit of money.

One worry I had in reassembling the sprockets is that they would not be properly aligned as there was a little play. Apparently this is the major selling point for shops to professionally rebuild them. To be sure, I used the camshaft for alignment, measured for concentricity, and then torqued the fasteners to spec. I then tested operation by blowing air through the passages. All seemed to be in working order so I bagged them up until I was ready to use them.

Dang, if my STi ever falls into that state I don't know if I would have it in me to go through all that.

With a downpipe and catback on an STi there should be some engine management involved. Did this come with a map loaded to account for those changes? Running those mods without an updated ECU map can cause problems.

Heck, even with a proper ECU tune these engines can be finicky. I cracked the ringlands on mine (it is a 2008) but Subaru was nice enough to rebuild it for me under warranty. That was during a time when a few model years were blowing ringlands like they were made of paper mache.

In reply to wrex77:

To be fair this car did have a lot of miles, but yeah...scary! Did Subaru end up extending the warranty for ringland failures?

Yes, the previous owner had a basic stage 2 tune from Cobb and included the Cobb Accessport with the sale. I think I will probably be reinstalling the stock downpipe and removing the tune.

Now for the fun part: reassembly. I love working with clean parts. I installed an upgraded oil pickup tube (no sense in repeating Subaru's mistakes), new oil pan baffle, new oil pump and a new oil pan. You may ask, "Why not clean the old oil pan?" Well, here's the old one:

Not only was it dented, it was almost rusted through. I then installed a new oil cooler, coolant hoses, and a new Wix oil filter. Apologies that I don't really have good pictures of this; I got excited and blasted through the work without pausing for photos.

I used all new gaskets and seals from the master gasket kit I had purchased as well as replacement rubber hoses. Have I mentioned how nice it is to work with new, clean OEM parts!?

I took one last good look at this:

It's a shame to cover all that beautiful aluminum up, but I'd rather have a running car than an art piece in the garage. I slowed down and worked at a painfully slow pace when installing the cylinder heads as I didn't want to make any mistakes. I meticulously cleaned the head bolts, installed the cylinder heads and followed the factory torque sequence. Using assembly lube, I reinstalled the camshafts and torqued the cam caps to spec. I then installed the oil control solenoids for the AVCS, along with new oil lines, and new banjo bolts. (I will likely rant about these later. Subaru decided it would be smart to install banjo bolts with fine mesh in-line filters installed for the oil lines going to the turbo and each AVCS solenoid. You can probably see where this is going.) I reinstalled the cam covers and stepped back to admire my work:

All this work just to flip it? Damn....

Did you reinstall those mesh screens? Those stupid things were the reasons so many of these motors popped. I'd leave them out.

In reply to Tony Sestito:

Nope. I believe Subaru actually instructed dealers to remove them as the easily clogged screen was wiping out turbos. I actually ordered the OEM parts but didn't find screens installed.

I wouldn't worry too much about the broken AC tensioner, they break easily, as the design is rather lacking. It places too much torsional rigidity on the part, in relation to the centerline of the tensioner. They all seem to be the same design from '98 to current. I'd love to see an aftermarket manufacturer make an updated replacement design, but that's asking alot.

I wouldn't say that your car is any more prone to problems though, based on a salt enviroment, it just has miles on the car, things break or wear out. It's just life.

I always thought Subaru's were ultra tough and reliable. Then I started following builds on the FFR 818. Boy do they have problems, and especially if they have been modded. I still think it ended up to be a poor choice for FFR to use the Subaru as a donor, but that's not my cross to bear.

In reply to D2W:

Maybe people think that since it's a Japanese car, you can treat it like a Camry and forget oil changes?

In my opinion, Subaru DOHC turbo engines are a cool idea with a couple points of poor execution. A huge part of that is probably in trying to keep overall powertrain cost reasonable. I think the STi was extremely bold and ahead of its time when it was introduced over a decade ago, but they haven't progressed far from then.

The STi probably gets a worse rep for reliability than it deserves because of the customer base. Besides modding (I shouldn't get started on that) I think a lot of owners are young, get financing, and can't really afford (or don't bother to) maintain them appropriately and drive them hard.

D2W wrote: I always thought Subaru's were ultra tough and reliable. Then I started following builds on the FFR 818. Boy do they have problems, and especially if they have been modded. I still think it ended up to be a poor choice for FFR to use the Subaru as a donor, but that's not my cross to bear.

I have had 7 of them in various guises (Outback, WRX, etc.), they are not appliances but do good maintenance and you can beat on them. They will come back looking for more.

Most of the issues are related to either the Previous Owners or the 2.5L turbo engine. I had either 2.5L NA or 2.0L turbo engines.

They are getting cheap enough that the DSM crowd that used to blow up 4G63's are now plowing up EJ257's and 255's. You can't play around with intakes and exhausts on them without a tune.

enginenerd wrote: Yes, the previous owner had a basic stage 2 tune from Cobb and included the Cobb Accessport with the sale. I think I will probably be reinstalling the stock downpipe and removing the tune.

Keep a Stage 1 tune on it.

The Subaru factory tune is notoriously lean, in effort to hit emissions targets and can cause issues.

Running lean actually raises NOx levels, but it can help light the cats off.

Typically running a lean tune is for mileage, one of Subaru's Achilles heal.

Dunno, lots of stock STi motors blew up with very little mileage on them because of the stock lean tunes, bad ring lands, etc. Then there's the cracked oil pick up that you've experienced.

Every manufacturer has their issues but I wouldn't call Subaru a paragon of reliability or engineering excellence.

In reply to enginenerd:

The factory lean tune was exactly why I had Cobb protune mine, without any mods. Just wanted reliable smooth power. Apart from a catback exhaust so I can actually hear it, all my mods are suspension, bushings, brakes, and so on.

They never did fix the warranty on the ringland issue. Mine was under warranty at the time with only about 30k miles on it.

That was 5 years ago and it has been problem free since then.

There is a certain type out there that buys this car, mods it carelessly, and then beats on it mercilessly. I think a fair portion of the bad rep comes from that.

Using the old timing belt looped about various components, I installed the freshly cleaned cam sprockets. These are really torqued on there, so I was careful to make sure there wasn't any slippage. I used a paint pen to mark the torque angles specified by the service manual and went to town with a large breaker bar.

I then installed all the new timing belt tensioner and pulleys that were included in the Gates timing belt kit. I had installed the water pump early on when working on the short block.

I triple checked that everything was aligned properly, sprayed a little oil down each cylinder, and then checked that the engine would turn over by hand. All good!

I was then ready to install the intake manifold assembly. However, it seemed a shame to bolt on years of grime to a very clean engine. I decided to disassemble it to clean, extract a few broken fasteners, and test operation.

As you can see, there is a lot more than just a simple intake manifold in this assembly. Included is the throttle body, four tumble generator valves, TGV motors, fuel rails and injectors, a wiring harness, and a whole bunch of rubber hoses and ducts. It was a mess. I started by disassembling everything.

Removing the actual intake manifold was easy enough, but some of the small bolts were corroded and snapped off. You can probably spot a few of them in the following picture of the TGV/fuel rail assembly.

Essentially what you have here is 4 separate butterfly valves. Each bank is individually controlled by the attached motor. Somebody more versed in emissions controls can probably explain the purpose of all these additional points of failure better than I.

I removed all the fuel lines, injectors, and rails. I cleaned them all meticulously, installed new gaskets on the injectors, and set them aside. I then tested the TGV motors to verify that they were working properly. Once satisfied, I cleaned all four TGV valves and the motors. I cleaned the intake manifold thoroughly and then replaced all the rubber hoses. I removed all the old tape and plastic that was falling off the wiring harness and rewrapped it almost exactly as it left the factory. Satisfied that everything was new and/or clean, I reassembled the whole thing and set it aside.

I realized that the large air duct going to the turbo was slightly torn. I decided to replace it now, as it would be a major pain to get to once installed in the vehicle. This is one big piece of hard plastic and molded rubber which was kind of annoying to replace as it wasn't cheap.

My forester popped a motor the same way. It was NA not the Turbo. I just swapped the motor, and then I had to replace the head gaskets on the "running" junkyard motor.

I am not a fan of Subie since then.