First you need an engine. I pulled this one from an 05 WRX that had very minor rod knock. Get the block and heads decked and cleaned up by a machine shop ($200 – pretty much the only thing I don't DIY). This block was in great shape, no scoring on the walls or bearing journal damage
These bearings are great and not very expensive (all main/crank and rod bearings for under $100)
Around 1999 Suburu switched motors from thrust bearing at position #3 to position #5. You can see the thrust bearing in the 5th spot on the far left. Not the small notch that indicates the orientation and keeps them from spinning in the case. Apply assembly lube
I'm reusing the crank because it was in good shape, no journal damage.
I tossed the EJ20 rods because they suck and I'm using 04+ STi rods (forged, so they say). Note the half bevel on the small end, and the single bolt (instead of a stud and a nut)
pretty cryptic but its a mostly matched set I guess?
clean up the rods and insert the bearings (again notice the notch)
Get out your torque wrench. I luckily found this digital Snap-On one from a pawn shop for
FHI logo faces front. I don't remember the torque spec. 36ftlbs maybe?
Don't forget the o-rings.
Drop the other half on top. Don't forget to add some RTV gasket sealant (I forgot, and had to pull it apart again and add it…)
Realized I didn't buy new block bolt washers (with gasket)
Another trip to the dealership
Don't forget the tiny bolt up underneath!
Match A/B pistons to what the block was machined for / measured at. 11112 is the main bearing measurement, which I usually ignore.
These pistons were in really good shape so I'm re-using them. Dropped them in a bucket of parts cleaner for a few days while I did everything up to this point
I'm reusing the rings because I'm cheap.
As you can see, no skirt wear, hence me reusing them.
Make sure the rings don't rotate from their intended position when you compress them! this is very annoying
2 dots face forward. Note the A stamp
Yes I realize this looks wonky
You wrote down which bucket went where, right? Otherwise you'll have a LOT of measuring and swapping
You can't replace the cam caps, they are machined to the head. So don't screw this up.
Notice "3I, 3E, 1I, 1E" referring to piston number and intake/exhaust. Don't mess it up.
I cleaned these up with a wire wheel and reused them, since I forgot to buy new ones at the dealer. As long as they aren't chipped, they're fine. Try not to wear them down too much, though you're filling the gaps with RTV so its probably not a big deal
Had to make another trip to the dealership for the filler tube o-ring and filler cap gasket
A bit of oil inside and out so it slides in nice
tap it in
Razor blade works
Clean this REALLY well and reuse it (unless you're upgrading. I'm staying stock for this motor). Don't forget the o-ring and RTV when installing. I forgot the o-ring and had to take it off and redo it… not the first time that's happened.
wrist pin access hole, rear main seal, and oil separator plate/cover. Rear main seal already installed. this is tricky. I usually use a block of wood to tap in most of the way then carefully go around the edges again with something thinner that fits in the groove.
aka the "little diamond plate". don't forget the o-ring
The oil pain is usually the grimiest part of a Subaru motor. Stupid timelapse here: www.youtube.com/watch?v=dVE3F8iMYpE
Make sure there's no gunk in here, no metal bits, etc.
Why the fuck is this o-ring so expensive??
my tube of black 3M RTV was done so I busted out the official Fuji threebond
Don't drop those little bolts into the engine. I've done it, they're very hard to get out.
Make sure this is clean too, and don't forget the o-ring
Tossed the piece of crap stock catted up-pipe and sourced an STi catless up-pipe. This one had a rattly half of the heat shield which I removed and wrapped with heat tape
nothing special here, just stock. If you take any of the joints apart, replace the gaskets
Not shown: Attach the up-pipe to the header and put it on in 1 piece, then install the turbo/uppipe mounting brackets. Don't do what I did and wait until the turbo is installed to do the brackets, its a pain in the ass.
Clean this REALLY well. Usually people just replace them to be sure there's no gunk in them, but they are expensive and I have a pressure washer, so I made it pretty clean. Don't forget the orange gasket
I probably should have replace that little elbow hose, but whatever
Parts master 67712 is the same as the Wix and cheaper
MAKE SURE YOU REPLACE THE INJECTOR O-RINGS. They are expensive ($8/each) but critical. I didn't and this shit leaked gas all over on the first startup and I had to dig back in here later and fix it which really sucked. Also tossed the idiotic green brackets; they suck
Replace the copper gaskets on the banjo bolts. Its worth it, believe me
OEM, expensive, but critical
The 02-05 WRX EJ205 uses basic copper plugs. Gap to .028"
white plug = front. black plug = rear
Get an OEM thermostat and gasket. Water pump can be Gates, but don't cheap out either.
The little mounting grommets should be replaced since they will always be petrified. Try not to break/crack the timing cover plastics
Slowly compress the tensioner dowel/pin and insert the securing pin
Match the notches
these will be loose (no valve actuation) and don't have to be perfect until you throw on the timing belt
This is tricky because the valves are partially open. I could set the top one but couldn't set the bottom one until i added the timing belt to hold it in place
Previous owner had already disconnected the AC lines when I got the car. Otherwise I would have left it still in the car without depressurizing the system
Look it up if you want to learn how to do this. Order is usually RH cams, crank, tensioner, LH cams, RH upper idler, water pump, lower toothed idler, RH lower idler, LH tiny idler
Don't over torque or you'll break the plastic. Don't forget to replace the seal/gasket strips. That cost me another trip to the dealership
Torque the flywheel bolts properly. You don't want it coming loose.
Don't overtorque the pressure plate bolts. They break easily
The crossmember is the grimiest part of the car (besides the oil pan)
Only took me 2 tries, because the first try I forgot to set the clutch fork into the throwout bearing. Don't forget to do that
They introduced these "quick connect" style in ~2005. They are pretty nifty, assuming you have the right tool to remove them
Don't forget to install the clutch fork dowel (with a bit of grease)
Also nearby: heater core coolant lines
Triple-check everything and do a first startup. Put a few miles and heat cycles on it and then change the oil