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Or maybe "semi-overhaul?" I'm hoping NOT to take the block apart.

In the coming weeks hopefully, I'm going to be removing the engine on a bone stock 2004 WRX EJ20 (wagon, 108,000 miles) due to what I'm pretty sure is a burnt valve. Only 30 psi in cylinder 4. Maybe it's a cylinder ring but I doubt it. I didn't do a leak down test... Regardless, I need to take it apart...

Rather than spending hours scouring all the WRX forums for tips I'm reaching out here.

Looking for advice on "must do's," part numbers, things to watch out for, tricks and techniques, links to write ups, that kind of stuff. 

Not looking to do any crazy upgrades, just want to get the car running again, but if there are inexpensive, quick and easy upgrades, that don't require a tune, I'm down for that.

At the bare minimum I will be: 

  • Taking the heads to a machine shop for a valve job.
  • Will probably have the heads decked, unless they're well within the factory tolerance. 
  • New head gaskets of course (recommended brands? Six star? OEM?).
  • Timing belt, pulleys, water pump, etc (I'll probably go with an Asin kit...).
  • Replacing all the obvious seals; Cam seals, valve seals, valve covers, etc..(Part numbers???).
  • Spark plugs.
  • Following the FSM to a tee. Or you know, within reason anyway. 
     
  • What if anything can I do to service the turbo?
  • I want to replace the fuel injectors. Recommendations?
  • Any must have special tools? I did the engine on my EJ22 and got by with what I have...
  • Head bolts? My conclusion after hours of research was that Subie head bolts are 100% reusable, despite all the debate. Am I crazy?
  • Any other advice is welcome!

Thanks in advance!

BC

 

 

Edited by bodhicheetah
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@GeneralDisorder Will have an opinion on this, I'm sure.

When I rebuilt the EJ205 in my bugeye I was on a budget, but didn't want to cut any corners.  My engine had spun a rod bearing and so the quickest route was an OEM shortblock.  All the ancillary parts were OEM, unless being replaced with aftermarket.  I added phenolic spacers between the intake manifold and the head, a lightweight flywheel, uppipe, and Group N engine mounts while the engine was out of the car.

My other suggestions include:

  • Go slow and read as much as you can before turning any wrenches.  Lots of good content on NASIOC, IF you know how to filter out the noise.
  • Keep things clean.  Tools, parts, etc.  Bag up the engine when you're not working on it.
  • Break in the engine hard, don't baby it.  Don't build boost or rev over ~4k rpm, but accelerate quickly and do as much engine breaking as possible in the first dozen or so miles.  My engine doesn't burn a drop of oil and still makes great power 50k miles later.
  • When in doubt, ask GeneralDisorder what to do next before moving forward.
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It would be comparatively rare to see a burnt valve at 108k. Typically don't see these before 150k+. Remember the first valve adjustment is required at 105k.....

But the 205 doesn't typically suffer from piston failures either so...... 

You have a mystery on your hands for sure. If it were me and you have low compression, I would hookup either a leak down tester or smoke machine to the cylinder in question and find the source of the loss before tear down. Best to know what you are looking for rather than guessing. 

Can't really say much more than that at this point. Need to find the cause. 

GD

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Awesome, thanks for the replies.

I figured I'd be taking it apart anyway, weather it's a burnt valve or a piston ring, but a leak down test seems pretty easy so...I guess I'll rent the tester and try to do the test this weekend and report back.

I bought this car for cheap off a friend of mine who was the original owner. Which means he'd been driving it since he was like 16 so who knows how it was treated over the years. Also I think he was a fan of Mobil1 which I've heard is really not so good for WRXs? Aside from the misfire though (maybe I should have mention the P0304?) the car is in pretty decent condition.

I'll let ya know how the leak down test goes!

Cheers!

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you did the ej22 already so most things are the same, here are the differences:

ej205's came with plastic cam pulleys, also the cam bolts need allen key's.  they are a pain most of the time, look up some videos on how people get them off beforehand.  I've removed rounded off bolts with a bolt extractor.  can't heat the ones with plastic cams without weakening them.

not much you can do with the turbo.  check for turbo shaft play when it's off, the exhaust housing likes to crack around the wastegate port.  it's safe to continue to run it if it still seals, just not optimal.

crank bolt is on much tighter than ej22, 133ftlb instead of 95 in the ej22.  if you don't have the crank holder tool loosen it with the engine in the car and someone standing on brakes in gear.

headbolts are reusable if not corroded.  wipe off and clean lightly, no wire wheel. if there's no corrosion it's safe to reuse.  

consider reringing the pistons since you're already in there

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Wicked. Thanks for the tips on the cams, just the kinda info I'm looking for. Will definitely look for vids on that. 

I've removed and installed a Subie crank bolt 3 or 4 times now and I think I"m gonna bite the bullet and spend the $40 or so for a holder. I've gotten by without it but it's always been a bit of a hassle, especially when I'm by myself and have to figure out how to jam something against the brakes, lol. 

Cheers!

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Alright. Did the leak down test, but, and I feel like a dufus on this, major correction to add here, the actual mileage on this car is 147,505. I had the 108 number in my head from the title (which is dated about 2 1/2 years earlier than when I bought the car...). So maybe a burnt valve wouldn't be as mysterious in this case after all.

Anyway, embarrassment aside for the moment, there was air coming out of the exhaust, the intake, and the oil filler neck. Didn't see any bubbles in the coolant, checked all 3 caps. I totally forgot about squirting oil in the cylinder before the test so I'll probably do it again to see if less air comes out of the oil filler neck. Definitely seemed like most of the air was coming out of the exhaust.

I appreciate all the advice so far and look forward to further advice. I'm ready to start taking this puppy apart!

BC

 

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  • 3 months later...

@nvu @GeneralDisorder

So I'm at the point where I'm about to take the pistons out to make sure the ringlands are nice and clean. I bought a new set of rings (OEM from the dealership) and now I'm all paranoid that I need to hone the cylinder walls. Is it ok to just throw new rings in without a hone? The original crosshatching is still quite visible. 

So, yea, questions:

  • Is it a must to hone the cylinders just for new rings?
  • Do I need to "break in" the new rings? Special oil, etc....
  • Also I've heard you can't twist Subaru rings on like most people do. Is that true? I don't have piston ring pliers but I can't get them if I have to.

Any input on those three questions would be much appreciated. I'd rather not split the block and drag it to the machine shop, but if I have to, so be it.

And btw, it was indeed a burnt exhaust valve, cylinder 4, that was causing the low compression/miss fire.

This project has been dragging on and on as I haven't had as much spare time as I hoped. I am getting pretty stoked now to put it all back together. 

Cheers,

Dan

 

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no honing needed

after the first 50mi change and all looks good,   it's a turbo so give it mild boost to seat the rings. lots of engine braking in between. running conventional oil until you hit the 1000mi mark is fine.

never heard of subaru rings needing a tool, i've always put them on by hand. do check the ring gaps on the block before putting them on the piston.

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Cool, thanks for the replies. No hone it is. I'm still a little nervous about the rings not seating, but.... not having to split the block, take it back to the machine shop, reassemble it....I'll take my chances!

@el_freddo When you say "standard practice," are you talking about breaking in the engine because of new rings, or the practice of "twisting" the rings onto the pistons?

@nvu  I would normally use Rotella t6, but that's synthetic, and as far as I know you can't get 5w40 conventional oil.  Would you run 5w30 conventional for the break in? And you're saying to do a quick oil change after 50 miles?

I was going to do a quick oil change anyway just in case of any cleaning residue, or heaven forbid, aluminum oxide (which is another huge concern of mine, but perhaps for a different thread) from the Red Scotchbrites that I used to clean the block surface and piston crowns. 50 miles sounds about right.

This morning I was experimenting with the rings and I'm pretty sure I'll be able to get them onto the pistons without twisting them, so not really worried about that anymore. 

Thanks again!

D

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yes nonsynthetic, get the cheapest oil you can find for the initial startup.  when it first fires, check for leaks, check for air in coolant system.  all you want to do is make sure everything is in order and let the car warm up, catch it if something's wrong with the coolant bleeding and it starts overheating.  coolant routing on a turbo is way more finicky than ej22.

when you're sure it can idle and cooling fans cycle on and off say for 20mins.. take it for a short drive

the specialty break in oils you see have high zddp content, that's used for breaking in aftermarket cams.  pretty much any standard oil is fine, 5-30 is fine.  i loosely follow the 5-50-500 rule; change at initial startup-5mi very cautious on everything.  change again at 50mi it may have metallic specks depending on machine work.  change at 500, should be fairly clean, less specks ok, more specks is problem, engine comes back out.  by the 1000mi change it should be broken in and ready for high rpm and boost

Edited by nvu
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Wicked, thanks for the detailed info! 

I’m also going to attach a rare-earth-magnet on the oil drain plug for the hell of it, make it easier to spot any metal filings (ferrous metal at least). 

At this rate it may be a month yet before I’m ready for start up, we’ll see. But it’s a relief to have a solid break in plan. 

Also, found this thread with GD explaining why honing isn’t necessary. Very reassuring!

Thanks again,

D

 

 

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On ‎3‎/‎21‎/‎2020 at 1:35 PM, bodhicheetah said:

I’m also going to attach a rare-earth-magnet on the oil drain plug for the hell of it, make it easier to spot any metal filings (ferrous metal at least).

Based on the experience of KillerB Motorsports (or was it Turn in Concepts?), I would highly advise against this.  They outlined  (non-scientific) test they ran where having a magnet on the ENGINE drain plug was not helpful and actually detrimental, but failed to get too detailed when pressed.  You can find the thread on NASIOC.  TRANSMISSION oil pans and magnets are a different story, since they have steel particles suspended in the fluid vs. an engine which will only have steel particulates after a something has gone terribly wrong.

Just a suggestion, feel free to ignore.

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Interesting. Found this article by Blackstone. His conclusion is that it basically doesn't do much either way, it's a difference of a few parts per million, doesn't really matter.

Intriguing that in some cases the iron actually increased with the magnet (again, only by like 3 or 4 ppm). I was thinking maybe a tiny bit of iron might get stuck to the oil pan because of the magnet, and then releases when you pull the plug and washes out in the sample? Who knows! I'm sure some kookball on Bob is the Oil Guy will figure it out someday :blink:

In any case, I just want to be able to clearly see any filings. I know you can see them suspended/shimmering in the oil, but I like the idea of seeing them on a magnet and being able to compare the difference between oil changes. And based on that article it doesn't sound like much of a risk, but thanks for the heads up!

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The shimmering in your oil is more likely bronze, copper, lead, tin, aluminum, etc. from your crankshaft bearings.  They might have a steel backing, but the wear surface is is non-ferrous metal, so a magnet on your engine oil drain pan/plug really isn't doing you any good, unless you're planning to grenade the engine and want to catch all the party favors.

Again, transmissions use mostly steel parts, which is why most OEM transmission drain plugs already have a magnet in them, and almost zero engines have magnets in their drain plugs.  Add one if you want, but your money would be better spent on a quick oil change after 20 miles of driving.

Edited by carfreak85
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I hear ya,  a magnet is useless :banghead:

Wish I hadn’t mentioned the magnet, but I’m still gonna put one in there, I have a half dozen on hand so no cost to me. I’m mostly curious about the rings wearing in against the cylinder sleeve (both of which are steel, I believe) If there are more filings at first and then less after each change...that would be a good sign.

In any case, consider it an experiment! I’ll report my findings if there are any. If nothing happens so be it...

:drunk:

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