2005 Subaru Impreza WRX engine rebuild

2005 Subaru Impreza WRX engine rebuild

Prep the block

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
ACL Race bearings

These bearings are great and not very expensive (all main/crank and rod bearings for under $100)
Prep main bearings

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
Prep other side

Assembly lube applied

Prep crank

I'm reusing the crank because it was in good shape, no journal damage.
source some rods

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)
Rod markings

pretty cryptic but its a mostly matched set I guess?
Prep rods

clean up the rods and insert the bearings (again notice the notch)
Rod assembly lube

Torque wrench!

Get out your torque wrench. I luckily found this digital Snap-On one from a pawn shop for
Bolt up rods > crank

FHI logo faces front. I don't remember the torque spec. 36ftlbs maybe?
Drop in crank, add o-rings

Don't forget the o-rings.
Match the rod positions to the piston bores

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…)

Block is mated! So shiny

Prep your case bolts

Realized I didn't buy new block bolt washers (with gasket)
Get the right washers!

Another trip to the dealership
Bolt the block together

Don't forget the tiny bolt up underneath!
Block measurements

Match A/B pistons to what the block was machined for / measured at. 11112 is the main bearing measurement, which I usually ignore.
Prep pistons

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
After parts cleaner, still kinda dirty

I'm reusing the rings because I'm cheap.
Soap + water + brush

Ring orientation specs

Pistons cleaned up!

As you can see, no skirt wear, hence me reusing them.
Piston ring compressor

Make sure the rings don't rotate from their intended position when you compress them! this is very annoying
Piston install specs

Piston in!

2 dots face forward. Note the A stamp
lube wrist pin

Line up rod through wrist pin access hole

Tap in wrist pin and add retainer clip

Pistons are in!

Close up the wrist pin access holes

Throw the block on the engine stand

Yes I realize this looks wonky
Ensure you have a beer

Freshly decked heads

Attempt cleaning carbon off valve face, then abandon the idea and move on

Head gasket

head dropped on

Head torque specs

Bolt the head down (stretch bolts use a specific order)

Install shimmed buckets

You wrote down which bucket went where, right? Otherwise you'll have a LOT of measuring and swapping
Assembly lube on the buckets

Cam cap torque specs. Don't overdo it!

You can't replace the cam caps, they are machined to the head. So don't screw this up.
Secure cams

Notice "3I, 3E, 1I, 1E" referring to piston number and intake/exhaust. Don't mess it up.
Drop in cams

Both heads installed!

cylinder head half-moon plugs

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
Dirty valve cover parts, etc

Cleaned & wet valve cover parts, etc

Cleaned and dry valve cover parts, etc

Install valve cover

Had to make another trip to the dealership for the filler tube o-ring and filler cap gasket
Install cam seals

A bit of oil inside and out so it slides in nice
Nifty seal installer kit

Tap tap tappy

tap it in
Prep oil pump surface

Razor blade works
Oil pmp

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.
Prep for crank seal

Tap tap tappy again

Prep rear of motor

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.
Install wrist pin access hole

aka the "little diamond plate". don't forget the o-ring
apply RTV to plate

rear of block done

Clean oil pan

The oil pain is usually the grimiest part of a Subaru motor. Stupid timelapse here: www.youtube.com/watch?v=dVE3F8iMYpE
Cleaned up oil pan

Cleaned inside of oil pan

Make sure there's no gunk in here, no metal bits, etc.
$19 o-ring

Why the fuck is this o-ring so expensive??
Apply RTV

my tube of black 3M RTV was done so I busted out the official Fuji threebond
Prep block surface and oil pan baffle

Don't drop those little bolts into the engine. I've done it, they're very hard to get out.
Install oil pickup tube.

Make sure this is clean too, and don't forget the o-ring
Oil pan installed!

Install engine mounts and weird little cover plate on the back

Prep up-pipe

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
Prep header

nothing special here, just stock. If you take any of the joints apart, replace the gaskets
Exhaust ports: before

Exhaust ports after razor blade treatment

Exhaust manifold gasket

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.
Oil cooler

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
Oil cooler installed

I probably should have replace that little elbow hose, but whatever
Oil filter installed

Parts master 67712 is the same as the Wix and cheaper
Install coolant crossover, dipstick, and some other coolant lines

Prep intake manifold and TGV delete

Deleting the TGV butterfly plates

No more plates!

Used JB weld and some bolts to plug the TGV rod holes

Reassemble manifold+TGVs+injectors

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
Razor blade the intake manifold ports on the head

Somehow cut yourself and bleed on stuff

Intake manifold on!

Install turbo… carefully

Replace the copper gaskets on the banjo bolts. Its worth it, believe me
secure turbo inlet pipe

Replace those copper washers!

Knock sensor

OEM, expensive, but critical
Spark plugs

The 02-05 WRX EJ205 uses basic copper plugs. Gap to .028"
Plugs installed

Coilpacks installed

white plug = front. black plug = rear
Install water pump + thermostat

Get an OEM thermostat and gasket. Water pump can be Gates, but don't cheap out either.
Install rear timing covers

The little mounting grommets should be replaced since they will always be petrified. Try not to break/crack the timing cover plastics
Timing tensioner

Slowly compress the tensioner dowel/pin and insert the securing pin
Set crank timing

Match the notches
Set RH cam timing

these will be loose (no valve actuation) and don't have to be perfect until you throw on the timing belt
Set LH cam timing

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
Ready for timing belt

Installed AC compressor

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
Install the rest of the fucking timing belt

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
Timing belt covers

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
Pretty much done! Put it on the hoist

Install flywheel

Torque the flywheel bolts properly. You don't want it coming loose.
Install clutch

Don't overtorque the pressure plate bolts. They break easily
Optional: clean up the engine bay

The crossmember is the grimiest part of the car (besides the oil pan)
Drop that bitch in

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
Install little stuff: coolant tank/lines and vacuum/boost lines

Reattach fuel lines

They introduced these "quick connect" style in ~2005. They are pretty nifty, assuming you have the right tool to remove them
Install clutch slave cylinder

Don't forget to install the clutch fork dowel (with a bit of grease)
Install starter

Also nearby: heater core coolant lines
Install alternator, belts, cover, throttle/cruise cables, etc

Install TMIC, BPV, PCV lines

Fill with fluids!

Triple-check everything and do a first startup. Put a few miles and heat cycles on it and then change the oil
Source : elislider from Reddit