The SVX was known for its transmission failure because the flat 6 EG33 was the most powerful Subaru engine produced at the time. That paired with the weak 4EAT transmission was a recipie for disaster. Shortly after my purchase of Miki, she started showing signs of transmission failure. The previous owner had swapped the stock SVX transmission with a 4.11 transmission out of an Impreza because the original one had also failed. Unfortunately for me, the transmission they pulled from a junkyard Impreza wouldn't last more than 2000 miles of my ownership. With that in mind, I decided to dive into Miki and install a 5 speed manual transmission.
Subaru Manual transmissions that fit generally are known to be able to handle more power than the 4EAT, potentially improving reliability
5 speed manual over the 4 speed auto has the added benefit of potentially improving fuel economy
A manual swap gives me the chance to learn more about how the SVX and cars work in general
Driving manual is fun :)
Before I began the swap, I needed to gather the necessary parts for the swap. Over the course of a few months, I gathered the necessary parts before starting the swap:
Subaru 5 speed manual transmission
Brake/Clutch pedal assembly
Clutch master cylinder
Clutch slave cylinder
Clutch kit
Compatible front drive axles
Lengthened rear driveshaft
Manual starter motor
Shifter assembly
Transmission brace and mount
Various necessary fluids
Misc. hardware
Lots of patience
Removing the transmission went relatively smoothly. It was here where I discovered where the transmission had failed. The flexplate connecting the engine to the transmission had broken at the bolt holes, causing loud noises and poor power delivery. I could have replaced it to get the car running again, but I was already committed to the swap, so I carried on...
To properly install the modified pedal assembly, I removed the seats, steering rack assembly, and several other interior components. I then retrofitted the new pedal set and prepped the center console for the shifter assembly before reinstalling the parts I removed...
With the pedals finished, I proceeded with installation of the clutch/flywheel assembly on the engine, as well as mounting the clutch master cylinder to the firewall. This process involved rerouting some of the wires that went into the engine bay and relocating brake lines. The clutch master cylinder was mounted on a hole where the electronics run though and I'm currently working on a solution to remedy the hole in the firewall (the extra heat is welcome in the winter though). Currently, the clutch is mounted with a series of standoffs and 3D printed spacers!
Up to this point, I had been working on Miki mostly alone, but I was able to get help from my friends to get the transmission mated to the engine. 5 of us worked in harmony to fit the 5 speed into the engine (4 under the car, 1 observing from above.) Thank you to Logan, Jon, John, and Sam for the help!
After that, I was on the home stretch! Wires were connected, new front axles went in, and fluids were bled.
While I waited on my modified shifter assembly to arrive, I finished everything else! The modified driveshaft went in, along with the interior. Late on an April fools night, Miki started for the first time after being parked in the garage just one month prior!
2 weeks later, Miki was on the road again, with a new (to me) transmission and a knobless stick out of the center console!
The 5 speed swap is still a work in progress, but Miki is functional now. I'm thrilled with the results! I learned so much through the process, and it has given me the confidence to step outside my comfort zone and try more new things, even if the idea seems out of reach. The few things I want to eventually finish on Miki are:
Permanently secure the clutch master cylinder
Get a shift knob
Make a shift Boot
With the manual swap complete, I decided to take Miki on a cross country road trip from my university in Indiana back home to California. Unfortunately for me, Miki suffered a catastrophic failure 4 hours in to the 40 hour road trip and I was left stranded. I got Miki towed back to my house in Indiana, and I continued on my journey to California over the summer.
My initial assumptions for the failure mode was the water pump. Coolant was gushing out near the thermostat housing, and Miki was overheating. When I returned to Indiana in the fall, I did a more in-depth analysis of the damage. Removing the timing cover revealed a shredded timing belt among other damaged timing components. It seems to me that water pump failed and seized up, shredding the timing belt and destroying one of the pulley flanges in the process. Thankfully the SVX is (for the most part) a non-interference engine, so the ripped timing belt had no negative affect on the rest of the engine components. With that in mind, I set out to replace all my timing components while giving Miki a couple upgrades along the way.
Miki's timing components were far gone, and I was fortunate enough to have a full timing kit with a new belt and all the idlers. I also purchased a new water pump and thermostat to replace the ones that were destroyed during the mechanical failure.
Aside from the transmission problems, the SVX is known to have overheating issues, as its dual pass radiator isn't always up to the task cooling the 3.3 liter flat 6. It also has plastic end tanks, which are notorious for cracking and breaking.
Several miscellaneous things in the engine bay were bothering me because they were either slightly damaged, worn, or just visually unappealing, so I decided to play the "let's fix it while I'm in there" game as well
I first started by removing the radiator and timing covers to reveal the damage I mentioned above. I was pretty worried about the internals at this point, but I collected myself and pushed on. At this point, I decided to go all out and replace or restore anything I could easily get my hands on. I had a set of hard fuel lines off another SVX that was not rusted, so I decided to swap that. That involved taking off the intake manifold which I also decided to replace because of a dent on the mating surface of the throttle body causing a vacuum leak. That meant transferring all the sensors and hoses to the new intake manifold along with the new fuel rail. Since I had access, I also removed all the accessory mounts for wire brushing and a fresh coat of spray paint. One interesting thing that needed to happen was removing one of the cam pullies, as the timing belt had destroyed one of the flanges. Because I didn't have any vice grips, I ended up improvising with a bunch of weaker clamps. It worked like a charm!
With all the parts restoration and replacement underway, it was time to add some upgrades! I purchased an all aluminum PWR radiator for Miki. This thicker triple pass set up should ensure engine temps stay nice and cool (and it looks sick too!) The other benefit is that this design throws out the plastic end tanks for welded aluminum, giving me the peace of mind that my radiator won't blow up on a warm day. The new rad is a pretty tight fit, but it looks great! Rad if I may say... After a lot of cleaning and assembly, I was left with this satisfying result!
This upgrade definitely not planned, but it ended up being a welcome one. It gave me a good chance to look at the smaller details in the engine bay and make an effort to clean things up. You will likely see me working through some other parts and restoring it to prevent rust in the future. Miki has been in the rust belt for most of her life, so there are definitely places where corrosion has begun to show signs. My goal is to eliminate these places, one spot at a time. I also got new wheels in the middle of this part of the project, so Miki's first drive after these repairs were on these nice STI wheels.
Now that Miki has been running well for some time, I figured now is a good time to start adding some performance! I decided to start with some suspension first and see where it all goes.
I got a couple things to dial in the suspension for Miki at this point. This included:
Ceika Type 1M Coilovers with helper springs and camber plates
DRW polyethene front lower control arm bushings
WRX Moog adjustable rear control arms
The first step for these sets of mods is the bushings. The 30+ year old rubber bushings have defiantly seen better days, and they are quite worn. I removed the lower control arms (after grinding down a few bolts that didn't want to come out) and added them to a bonfire my roommates were having at the time. The worn bushings slowly burned away leaving me with the steel sleeves surrounding them. I cut the sleeves out with my roommates pneumatic saw and had the control arms powder coated to prevent any rust in the future. After getting them back from powder coating, I pressed in the blue polyurethane bushings from DRW Bushings. They fit nicely, and the control arm went in fairly easily.
The coilover install honestly was probably the most straight forward and easy mod I've done to this car. I guess that goes to show how many things needed to be fixed before I felt it was ready for this. The main annoyance for this was taking apart the rear interior to access the rear struts, but it wasn't too bad. The main challenge was setting the ride height and sway bar linkage position properly. I ended up messing up the sway bar linkage position, leaving it too low and bending them. Thankfully, the parts car I had still had the linkages in tact. Because it was a FWD model, the linkages were actually thicker, so that also worked out in my favor when I replaced them.
The rear control arms was a little more difficult, mostly because of the old hardware. The nut decided to round itself, so I resorted to grinding it out of existence. This also meant I ground down the eccentric bolt in charge of the rear alignment. Because the Moog arms are adjustable, I stacked two washers and ground them down to fit in the bolt slot in the subframe. This ensured both arms were bolted in the same position to aid in alignment. With those in, I reassembled the rear end and took Miki to an alignment shop. Unfortunately for me, because of the way the fenders sit, my rear wheels are a little tucked, causing many alignment shops to turn me away. Fortunately, I found one, and now everything is nice and straight.
At this point, Miki has reached a point that was dreaming about when I first started on my car journey. The path and timeline I took to get here was not quite what I had in mind, but I made it (faster than I was expecting actually)! The coilovers really changed the feeling of the car, taking it from a 90s GT car to a more performance oriented street car. The spring rates are quite stiff at 5k front and 8k rear, but I think they will perform well under spirited driving conditions. Although the list of things I'm planning on doing continues to grow, writing this blog has given me a chance to reflect on all the hard work I have done. I've learned so much so far, and I know that there is so much more in store. If you've made it this far, thank you for reading! Your interest and support means a lot to me.