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Just another lowly GM6 build

16K views 165 replies 21 participants last post by  r0bman 
#1 · (Edited)
Hi everyone, just wanted to share a project I’ve been working on for a very long time. I know it's nowhere near as fancy as 90% of the builds here but maybe someone might appreciate it :)

I was a Subaru fan from as long as I can remember. A friend of mine took me for a spin in his Group N WRX in the early 2000’s and I was instantly hooked. He let me pull it up the starting line for rallycrosses, even though I had problems with the stiff 6 puck clutch, as a 12 year old I knew I had to have a fire-breathing Subaru of my own. GC’s always appealed to me more than the GD chassis, no doubt due to it’s rally heritage.

In about 2005, my father managed to find an immaculate ’95 GM6 in Florida for less than 500$. We drove it back the same week, thrilled to start our first ever build. Even with the piddly stock 1.8 and ancient tires the lightweight chassis had me excited. We didn’t have much of a budget to complete a full build immediately so things took quite some time. Sourcing a EJ255 from a wrecked LGT through Copart was the official start of the project. I still remember the day we started salvaging parts and my father standing over me, teaching me everything I needed to know about wrenching. We painstakingly took apart the donor car, making note of every bolt and hose location. A couple busted knuckles and lots of “I told you so’s” from him and we managed to get everything lined up and positioned in the engine bay. Wiring was another obstacle. iWire wasn’t even on the map when we sat down and spent dozens of frustrating hours going through schematics of the LGT harness and the 04 STi ECU we were going to run our motor with. I learned to solder, terminate wiring, and most importantly patience during that time.

Trying to fire it up for the first time was a disappointment, an errant wire spliced in the wrong place prevented the ECU from getting power. Countless hours later we got it running with an open downpipe and bunch of angry neighbors. As a young teen that was by far the proudest moment of my life, a memory I’ll never forget. With smiles all around we took it for a spin, my childhood memories finally coming true. Even though it had a stock tune I felt I could take on anything on the road and win.

After a few months of driving, the stock motor dropped a valve, splitting a piston in half and scoring the cylinder walls. Frustratingly we pulled the motor, took it apart and started calling shops for options on how to properly build it up again.

Unfortunately school and other priorities got in the way of our build, and our Subie sat undisturbed in a garage for the better part of a decade. A year ago I saved up enough to fully build a longblock, and this time it was my turn teaching my dad how to gap rings, assemble heads, and time the motor. It took us a while but we got it together and running last summer. A few hiccups along the way and we went on our first test drive in the new motor on a hot July day, no AC of course. I still remember him yelling at me for throwing on a silly burble tune that sounded like an M240 as we drove down residential neighborhoods. Unfortunately, the drive was cut short by a total loss of power, SBF-5 was blowing. Swapping them out didn’t help so we pushed the car 2 miles home cursing the whole time. We spent days trying to figure out what was going on, the heat didn’t help at all so decided to wait until the cooler fall months to take out the wiring harness and try to find out what was going on.

My father died of a massive heart attack on September 11 of last year, a few days before we were set to pull the dashboard and harness.

I couldn’t bear to even look in the garage for months after without completely breaking down. I’d never again pass him sockets and wrenches as he racheted underneath the car for those lower downpipe bolts or have him hold up the fifth iteration of an exhaust we were trying to make fit. Everything related to the car reminded me of him, how I could always ask him for advice at a moment's notice, knowing that if I screwed anything up he'd always have my back. Now I was on my own, it was all up to me to keep going. This might sound silly but until this this day I can still hear his voice every time I work on our projects, as if he never left my side.

Earlier this year I got it running again. It was something silly, just like he said it would be. The main relay was faulty and only one contact was clicking, providing power to interior electrical systems but not to the ECU. A stupid 10-dollar part prevented us from enjoying our newly built motor together for months, something we will never do together again. That first fire-up was bittersweet; I was elated that it fired up on the first turn of the starter, but he wasn’t there to hear the gravelly rumble of the 280 cams.

Since then I threw on parts we didn’t get to last year. I was dreading pulling rear knuckles due to the rear lateral arm bolt, but of course my father predicted this and slathered it in anti-seize over 10 years ago so they slipped right out to my surprise. Everything I touched reminded me of something he’d teach me, from spraying some WD40 on exhaust hangers to get them in easily to not bolting down one side the intake manifold down fully before hand tightening the other side so everything lines up.

I don’t know what my future plans are with the car, it could use a good coat of paint after 26 years and maybe some flares, but I’m sure as hell not selling it for as long as I’m still around.

Miss ya Daddy.

Here's some shots from last year, ill throw up some new ones soon.
86825

86826

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Engine
EJ57 case halves
Turbo Tuff I-Beams
CP pistons
ARP 625 studs
D25 Heads
Ferrea Beehive Springs
BC Stainless Valves
BC Stage 3 280 Cams
ID1000 Top Feed Injectors
V1 Perrin Fuel Rails w/ OEM FPR
Radium fuel rails/dampeners/fuel pressure regulator
Direct-wired Aeromotive 340 pump
Custom TGV Deletes
IAG 8mm phenolic spacers
11mm STi Oil Pump
Killer B Oil Pickup
Perrin Catless Up-pipe
Nvidia Catless Down-pipe
Vibrant Catback
Moroso Alum Oil Pan
TD06 20G Deadbolt Turbo
TurboXS Front Mount
MAC 3 port EBCS
AEM 3.5 Bar MAP
GM IAT Sensor
K&N Short Ram
eBay GC Radiator
Spal Fans
Evap Delete
TurboSmart Vee Port Pro
Group N Engine Mounts

Electronics/Control
ECUMaster Black with custom patch harness
Autosport Linear Oil Temp sensor
Lowdoller fuel pressure sensor
Lowdoller oil pressure sensor
Prosport Water Temp
Prosport Boost Gauge
Mech. Oil Pressure Gauge
AEM UEGO with 0-5v output to ECUMaster Black
CANChecked multi-gauge
Shorai LFX36L Battery

Drivetrain
Stock Clutch
Stock 5 speed
WRX 4 Pot Fronts
LGT Vented Rear rotors
LGT single pot rear calipers
1 1/16" 4 port master cylinder
Braided Lines
Hawk HP+ All Around
Group N transmission mount
Kartboy Shifter Bushings
Kartboy Trans Bushings
Kartboy rear outrigger bushing inserts
Whiteline Rear Subframe Lock Bolts
Whiteline Steering Rack Bushings


Suspension
DMS 40mm Coilovers
Cygnus Performance X-1 Coilovers
'04 STi Steering Rack
'05 STi Front swaybar
JDM STi alum. LCAs
Sparco Front Strut Bar
Whiteline Front Endlinks
Whiteline Front Swaybar Bushings
Whiteline Rear Endlinks
Whiteline ALK
Whiteline Roll Center and Bump Steer Kit
Whiteline Rear Swaybar Mounts
Whiteline Lateral Link Bushings
Whiteline Trailing Arm Bushings
Whiteline 22mm RSB
Moog Adjustable Rear Lateral Links
ARP Studs


Exterior
JDM STi Ver. 2 Aluminum Hood
JDM STi Ver. 2 Front Bumper
JDM Clear Taillights
JDM Front Bumper Beam

Interior
Old school OMP Wheel
NRG Quick Disconnect
Custom CF center console panel
Stereo/Airbag Delete

To be installed
 
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#4 ·
Hey, I just picked up a GM6 and just want to thank you for sharing your build & the story of it.
Interest forums need more content like this. Please take the time & continue to keep us updated on your progress!
I definitely will! Looking through other other Member journals makes me jealous as hell as it seems the average user has outspent me by a few orders of magnitudes on their builds, but at least it gives me ideas of what I can improve.

Post up yours too!
 
#5 ·
First of all Welcome! That's a great story, and it's clear how much you love the car. I'm sorry about the loss of your father, but it sounds like you have a lot of great memories with him and working on cars. You guys built a tidy little coupe...Thanks for sharing!
 
#8 ·
Thanks for the kind words everyone!

New update:
Bought a FXT radiator, clears the AC lines with ease but the fans are a bit tight against the lower coolant line leading to the oil cooler. Biggest problem is that my hood won't close!

Ill either have to notch the underside of my hood or borrow a TIG and modify the inlet. about a half an inch lower. Also had to invert the top support bushings since the rad is a bit taller.

 
#10 · (Edited)
Yup its flush against the bottom brackets. Stock fans that look like this: https://images-na.ssl-images-amazon.com/images/I/51VQ2AX71BL._SX425_.jpg

The left fan is touching the crossover to the oil cooler but I can grind away at the fan bracket a bit to get some room. Kinda dont want to spend 200 bucks just on fans and then have to make custom brackets to make them fit. I was surprised it doesn't fully fit since stock FXT radiators bolt right in apparently.
 
#11 ·
Spruced up my brakes a bit with a fresh coat of paint. Thought of going red but had a can of burnt orange paint in the garage so just went with it.



Also finished installing a center console gauge panel:


It's a mix of a ton of different mfgr's and the orange prosport backlight doesent match the red of the other gauges but as long as they work im happy!
 
#12 ·
On your hood not closing with the rad: I had a similar problem with my supposedly stock fitment koyorad. I ended up making my top rad brackets a bit adjustable (slotted them out a bit with a drill) and tilted the rad back another half inch or so to make it fit under a higher part of the underside of the hood. Not a good option for you if you already have fan clearance issues.
 
#19 ·
87038

87039

Had some free time over the long weekend to wire wheel the alternator, TB and AC, looks much better than before.

Also tackled the rust. Thought it was only a few spots but boy was I wrong. Tons of surface rust around the windshield, with zero body work experience I jumped in headfirst cleaning everything up. It's soaking in Ospho now, just waiting for some cooler weather to paint.
 
#21 ·
Also tackled the rust. Thought it was only a few spots but boy was I wrong. Tons of surface rust around the windshield, with zero body work experience I jumped in headfirst cleaning everything up. It's soaking in Ospho now, just waiting for some cooler weather to paint.
Oops missed this - nice! Were you able to save the upper molding? I saved the metal molding but lost the rubber trim. Going to snag up some U channel rubber trim.
 
#23 ·
Finally had a chance to paint. Wiped off all the ospho, cleaned it up with some acetone and put down 5 layers of 2k spray primer. Excuse the shit tape job, I didn't remove the headliner so trying to stick anything around there was near impossible
87070
 
#28 · (Edited)
Nice looking project man, its looking really good! Sorry to hear about your father, that sucks. As a father myself I am starting to think about what these kinds of projects will mean to my kids. I had a Miata my kids and I fixed up and my daughter is still torn up about letting that one go. We traded it for a Mini Cooper because I am just too big for the Miata, but we all still miss it terribly, driving it was like a mini adventure every time, and I know it meant a lot to my kids. I am hoping our Impreza coupe can be special for my kids like the Miata was, we all work on it together, and I think it will be a lot more tangible for them when its a running and driving thing.

Your dad would be really happy you kept up with it and got it running. Congrats!
 
#29 · (Edited)
Thanks for your kind words! I sure hope he's happy.

They really do mean a lot. That first straight pipe startup 11 years ago still resonates with me today. We've had the car for 15 years, I'm 30 now and consider the coupe one of my most prized possessions. Christmas/birthday gifts are nice but owning and working on a project car is the best experiences I've had with my father. Work with them on the project as often as you can, they will appreciate every second of it!
 
#30 ·
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87174


Popped the windshield in over the weekend, was MUCH easier than taking it out that's for sure!

Cleaned up the interior a bit, especially the dash. It faded a bit from years in the sun but a few layers of 303 made it look like new!

Also threw in an OMP wheel that my dad got almost 15 years ago. The horn wiring is kinda janky and jury rigged but it works at least. The wheel is a bit small for my liking but i'm keeping it.

Now I'm on the hunt for some in-shape sunvisors, the glue turned to crap and now they're drooping. Too bad they're not available anywhere. :/
 
#33 ·
Thanks, no luck so far :/

New issue came up, hunting AFR at idle.

Thought it was a vacuum leak since I sloppily threw the manifold back in a few months ago. Found a few and sealed them up but it still jumps from 10 to 17+ in random cycles at idle. Thinking the O2 was bad i threw a new one in, same issue. Checked my logs and the narrowband o2 is not providing signal until 2 mins in, and the heater circuit is down.

I'm getting a strong 14v signal coming in to the sensor, but looks like the ECU isn't grounding it properly to make a connection. I hope it's just a dirty ECU connector or something!
 
#36 ·
Came up with this shitty diagram:


1. 12V from battery and SBF-5 is solid, and can pull 5+ amps without a problem.

2. sensor ground to ECU is solid (0 ohms)

3. signal + and - are solid (0 ohms), ecu recognizes correct AFR after 2-3 minute warmup time.

4. pin 7 to engine ground is solid (0 ohms)

5. Resistance from "Ground to ECU" to battery neg terminal is 37-40k ohms, regardless of key position.

So now I have absolutely no idea where to go forward with this issue.

Can anyone help me out and get this thing up and running properly? Thanks!
 
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