'79 Brat EJ22 Retrofit Build Thread

[mka]

Hey all - my last old project subie didn't work out so hot for me, ended up having to sell due to various circumstances after getting her running again - lost steam when she needed an AC repair that was just a pain to chase.

Recently though I've jumped back in with both feet (up to my neck, it would seem) and I bought a '79 Brat with the original intent of breathing life back into the EA71 that was in it, however that would appear not to be in the cards for me. The freeze plugs popped when the little truck was parked (probably back in 1997), and with the water in the heads and valve gallery the studs have all but rusted the heads to the block permanently (as far as I can manage, anyway. I've included a photo of my skookum in this regard - someone may have some tricks and better luck pulling her apart and rebuilding than I but after a week of every penetrating oil mix, mallet, block of wood, and sledgehammer in my garage I have put that aside.) During my initial attempt to revive the old car I also found how hard it was to get critical components like front strut assemblies, 4x140 wheels, etc. It seems these parts are just getting harder and harder to source, and the ones I found on the used market were a bit of a gamble at best, so I Bought a '97 Impreza OBS with an EJ22 and 5 speed to swap in.

I'm hoping this build thread will help keep me somewhat accountable and also give me some motivation to document what I'm doing. I've always been in awe of folks who can put together a build thread or repair thread start to finish and have found a number of them extremely helpful in the past on other projects - perhaps if I detail what I'm doing here it'll keep me on track and give back in a way, as what I have in mind is no small task. I've only seen it done one or two other places that still have the photos and details available, and not in detail on this particular vintage of subaru, at least not to completion.

Anyways, enough blabbing on from me and onto the broad strokes of the project:

Take my 1979 Brat husk, and replace as much as is possible of the underlying driveline with the components out of the 1997 Impreza wagon while keeping the outward aesthetic of the old truck.

I've seen swaps like this completed on Gen 2 Brats, both with the entire driveline swap and just an EJ swap with an adapter plate. I intend to follow the former path as the original EA71 transmission would be short lived with the new engine, and since i'll be replacing a lot of the suspension components matching things up I would imagine will be easier.

Current state as of this intial post -

Brat:

interior is mostly gutted, still need to remove and recondition the dash and get a sense of the condition of the underlying components. Engine is out, but still need to pull the transmission and test fit the EJ. Expecting based on all the other Gen 1 swap documentation I've got my hands on to have to notch the frame pretty good to get clearance, and probably some significant transmission tunnel work too.

Impreza:

Interior is also mostly gutted, ECU is removed and in safe storage inside. Removed the dashboard, heater box and AC componentry. One good more push and I should be able to have the EJ wiring harness out to begin thinning that out. I'm considering attempting to retrofit the OBS A/C system into the Brat, but I have to look at the mechanics of how that might work and whether or not I'll have the real estate.

 

Anyways, wish me luck - I really hope I don't make an rump roast of myself with this one 😅

[mka]

Got the main bulk of the wiring harness pulled out this afternoon - It's pretty freeing to be able to just yank stuff out without worrying about "will it go back in where it came from and look good." (after labelling connections, anyway)

 

Still finalizing exactly what I'm going to keep vs what I'm going to abandon - but right now planning on transplanting most of the Impreza harness into the Brat body and adapting at the terminations where needed, especially since I'm not sure of the condition of the original wiring.

I'm also even more heavily leaning toward retrofitting in the impreza HVAC unit and lower center console trims. Taking a good imaginative sit in the gutted cab of the Brat holding the trims and HVAC parts up to the available space has me nearly convinced this is possible, especially since I also plan on transplanting the trans tunnel from the Impreza where that console and handbrake mounts up.

 

So far so good. Still a scary prospect of a project but even only at this point, I'm still learning a lot.

Edited December 15, 2024 by mka

[mka]

Small hiccup, probably the first of many. I've got a neighbor who has appointed themselves the code compliance patrol and as a result a letter from the city regarding the new donor husk. Vehicles in the open need to be registered and "Appear operable." Gotta give the neighbor credit, they work fast. Brought the donor home on the 11th, and the report is dated the 12th. Not even a full 24 hours. Some people, am I right?

Operation "put good roller tires on the brat" is the new name of the game, and operation "fast track the impreza stripdown" is shortly behind it. With rollers on the brat I should be able to rearrange the shop a little to let me push it in and out as I work on it. Gonna need to get it in there anyways at some point to start the fabrication work, so silver linings I guess.

 

[573417h]

hi MKA, is a car cover an option, as this will get around the "being in the open" part, i suspect your neighbour doesn't appreciate the current eyesore lol -regardless of what it might turn into. 

[mka]

Good suggestion - I'm ahead of you with the car cover and had it purchased the day I brought the donor home. It is now underneath said cover and I'll be turning it around to face the house so the missing hood isn't so apparent. I'm in full agreement that it's an eyesore, I'm just surprised at the quickness of the neighbor though perhaps I shouldn't be, our municipality provides a live app to report with now. Whether it is enough to satisfy the city, well, we will see. I suspect between the cover and having one of these in the shop at most times should be sufficient to keep everyone off my case long enough to cut what I need off the donor husk and send it to scrap.

Regardless, I've got inflated roller tires on both vehicles and the cover on the donor now. Going to clear some space in the garage/shop to push things in and out so I can start fabricating. Picked up the final major piece to the puzzle for a while yesterday as well - a relatively fresh 5 speed cable transmission - the only major part the donor didn't have.

 

[mka]

Code compliance issue is no longer - gave the compliance officer a call and he was extremely easy to work with. Donor husk is in the garage for the time being, but apparently a car cover will suffice if I need to move it back out into the drive.

That out of the way, we got the first test fitting of the EJ out of the way yesterday. It would appear that with only a slight extension of the mounting slots on the original crossmember, the new engine should drop right into it, but as expected the fit is very, very tight. It could (by my measurements anyway) be done without notching the frame, however that would leave mere millimeters of clearance at the back of the valve covers. It will still be a much tighter fit than its original chassis even with notching, so like past builders I will also be notching the frame. (Noted where I'm notching things out in blue sharpie in the photo.) I should have about a half inch of clearance on either side when that's complete unless I find a way to relocate that forward mounting bolt for the subframe - in which case I can probably get a little more.

I also have 99% of the original wiring harness out of the donor now, and I'm pretty decided on attempting a full retrofit of most of the newer components into the old car, including the HVAC system. By my eye everything *should* fit, but it will be extremely tight.

Since I'm also going as far as installing pretty much everything else of note from the impreza, I'm also considering either adapting the power steering rack to fit the old Brat crossmember, or adapting the Impreza crossmember to fit the Brat, although I suspect the simplest route would be to ditch the power steering in its entirety and just use the original Brat steering gear. My only concern there would be replacement of components on the steering gear down the line - I hate having to track down parts for weeks or months at a time.

These next few days I'll be pulling the old 4 speed from the Brat and starting on the frame notching job. Somewhere in there I'm also going to do a refresh on the EJ while it's accessible. Oil pump, rear main seal, timing kit, that kind of thing, but that will likely be after the new year holiday, especially since I forsee a lot of removal and reinstall of the new engine and transmission while i do the fabrication on the crossmember, firewall, and transmission tunnel to get those to fit where they need to be.

 

PS - as i build on this I'll be putting the parts and pieces I no longer need up for sale, including the complete but now partially disassembled EA71 engine. Maybe someone with more patience or skill can get that head free and give this thing a new life. Same goes with the transmission and other miscellaneous components as I go.

 

Edited December 22, 2024 by mka

[mka]

A little more progress today - got the old 4 speed out. The mounts were so tired from being out in the elements that i didn't even have to disconnect the fron suspension fully to disconnect the inner CV joints. Other than the thirty years of grime and the mounts though, it's in really good shape. All gears turn smooth and 4wd engages/disengages like it should. I'm more than slightly bummed to be ditching the selectable 4wd, but this thing will definitely not hold up to what I'm doing long term. It would be really cool if there were a retrofit or modification for these transmissions to get that to be a feature again but all research I've done seems to point to that being a very expensive proposition at best so AWD it is.

The trans case sizes are definitely different, and like everything else on this thing I have some fabricating to do to get the linkage to land where I want it in the cab. Having them sitting next to each other on the ground like this gives me some ideas - I think I might be able to just shorten the linkage or even get rid of it altogether to put the shift lever on the EJ transmission closer to the stock position of the EA71? I'll have to sit with it and have a think.

Also got the engine bay lightly powerwashed, then extended the slots for the engine mounts on the original crossmember in prep for the next engine test fitting. During the last test I measured from end to end of the mounting studs and found that the Impreza slots are only about an inch wider than the brat. (15.5" on the Impreza, 14.5 on the brat) The angle of the landing pads are similar enough to where I don't think those will need any shimming or major adjusting, so it's a matter of taking a step bit and an angle grinder to add the extra clearance at the ends. I'll be going back at it with a dremel later to tidy up the work. If you have a die grinder (which i should own but don't) this would be an even easier approach to this. Gonna try to hold myself to a higher than normal standard on this one, and I'll be cleaning up things as I go back through it during the project to clean up little things like the scoring visible from the angle grinder in these photos.

Probably going to try to sneak out of the house a little tomorrow on Christmas Day after the morning festivities and get a jump on the notching, maybe try for another test fit before I'm off the project until the New Year. I found out yesterday while I was staring around dissociating in the empty engine bay that there is an extra hole (second photo on the last post) that goes all the way through the frame and crossmember. This would be ripe to sleeve and move that front mounting bolt backward far enough to get as much clearance as possible if I either find i want more than the current configuration allows, or the more likely possibility that i f*** up on cutting into the frame and hit the existing bolt hole/channel by accident.

Once engine and trans are rough fit into the Brat it'll be on to front suspension transplant, and then I'm going to try to strip every other suspension part I'll need from the impreza in one mad scramble so I can scrap the husk and get my full garage footprint back. It's really tight in there and it's kiiiiilllling me. Somewhere in that kerfuffle I'll also be listing the EA block and trans for sale so if you're looking for one of those, hit me up or keep an eye out then.

 

 

Edited December 24, 2024 by mka

[mka]

A little more progress this week, but alas I won't be able to turn a wrench or start working on the next phase of the thing for a while, so next update will be in the new year.

Looks like every time i make a  step forward, a corresponding step backward shows up in the form of another problem to solve.

Firstly - the step forward: Successfully got the frame rails notched out - handily this exploratory cutting revealed that the extra crossmember hole is already reinforced inside and as such will not require me to sleeve it in order to move the mounting bolts out of the way for the frame work. it also appears that widening the mounting slots also did the trick and with the transmission removed and out of the way, the new EJ22 drops right in where it needs to be, plenty of room, way more than i was expecting to end up with. Just have to hit it with some rust converter and weld-through primer and box it back in now.

Secondly, the step backward - The original steering rack is now (just barely) interfering with one of the lower studs that mount the transmission to the engine block, so now I have to figure out a way to get that clearance back, none of the other builds I've followed mention this as an issue - either that or I just wasn't paying enough attention. . Options I've come up with so far are:

A) shift the original rack to the driver side of the slightly or maybe extend the shaft so the soft, disc-shaped connection (not sure what that part is called) doesn't interfere with the stud or transmission case.

B )  Transplant the power steering rack from the Impreza, which doesn't use this same connection to the steering column and thus should clear.  I'd planned on doing this anyway though I'd hoped to get the rest of the transplant done first for logistical reasons (It's easier to move two cars around when they both have working steering for as long as possible)  which

If any 2nd- gen swap guys have run into similar issues, I'm all ears - So far most of the stuff required for the swap into this earlier Gen 1 seems to be very similar to the later Gen 2's, just with less room to work. Hoping maybe one of y'all have a good suggestion. I'm debating at least for the mockup phase for the transmission, its requisite mounts, and the transmission tunnel modifications to maybe just remove that stud and see if I get lucky with the clearance on the transmission case.

 

Anyways, that's a wrap til 2025 - In broad strokes, once I've got the engine and transmission mounted and located, it's on to front suspension transplant, then stripping the rear suspension off the Impreza shell and scrapping that to get the space back to fabricate on the rear end of the brat.

[mka]

Annnnnd we're back from the holidays!

Thanks to my storage solution for the Impreza husk I'm pretty motivated to get that disassembly completed enough to be able to get the shell out of my shop, and in order to do that I've determined I need to be able to mount and store the engine and transmission in their proper places in the brat before I can start installing and adapting the steering and suspension components in around that.

First go at the transmission mockup was yesterday, but I didn't bother taking photos - it was a hassle to say the least, but i did learn some things.

1. The transmission doesn't just 'drop in'. Not even close. Kinda expected this, but I'd still hoped for a little miracle.
2. It's a difficult install without coming in from the bottom - next time I'm going to try to block the body up taller and lift it in from below with a HF special transmission jack.
3. As mentioned in the last post, I'll need to modify the steering setup, either by installing the impreza rack, or somehow shifting the existing one without inducing any gnarly bumpsteer. Any suggestions there would be awesome. I've since been in touch with a guy who built a similar '79 wagon and his solution was to chop up the bell housing. I'm not really willing to go and do that (yet.).
4. Lastly I'll need to modify both the trans tunnel and the crossmember. On newer builds there's enough room to stab the EJ transmission in just weld in an extra plate to relocate the mount holes to match. My particular car does not appear to have the clearance to do this, and I'm hoping not to put in a body lift so I will likely be adapting the EJ crossmember to fit in some way. If this proves to be fruitless or too complex I may explore the body lift at a later time. I'm planning on cutting the tunnel out just enough to get the transmission IN the car on its own, then I'll trim away as needed and splice the impreza tunnel in to get the bolt holes and mounting points I need.
    

These new tidbits of knowledge in hand, I got to some more fruitful work today disassembling and disconnecting the front suspension so I can remove the Brat's transmission crossmember. Dirty work, and so many of these bolts were caked in 30 years worth of oil/dust/dirt crud mix it was hard to determine where they all were and bolt sizes.

To be expected there were some siezed threads. I almost decided to just whip out the death wheel and start cutting, but I came to my senses when I remembered how hard parts are to find for these things so I'm going to do my best to affect a non-destructive disassembly where possible in the off chance someone needs some of the parts.

Lastly the other day I also scored a deal on some inexpensive coilovers - almost no miles on them as the guy bought them to keep his "good ones" dust free while getting bodywork. Lucky me, as I don't need fancy or clean at this stage. The stock impreza suspension was giving me a headache on how to install them and were really going to be tight because of the spring diameter, but these have a much thinner spring and some really simple camber plates - something I'm very very able to make in order to fit the stock brat towers.

[mka]

Spent a little more time on some further disassembly last night - got the control arms, sway bar, and transmission crossmember out without having to cut anything major - just one little bracket needed chopping to get the parking brake cable off - the bolt was so caked it was practically cemented on. I've also removed the steering rack so I can drop the engine and transmission on without running into the rag joint while I work out that problem.

After reviewing some other builds again (there are only so many I've been able to find) I may end up switching tracks and modifying the impreza engine subframe to fit in the Brat for an easier time getting the steering rack clearances I need in order to avoid chopping up the transmission bell housing. For now, however, I'm going to push ahead using the modified Brat subframe so I can keep the impreza actually rollable for a little longer. I need to put together a couple dollies for the husk so I can keep workflow going in my shop during the day, and once i pull the control arms, knuckles, steering, and front suspension components that becomes much much more of a chore.

I've got the camber plates sketched up and getting ready to be CNC'd  - very excited for that part. I'd like to design an adapter to allow for the install of these coils into the original knuckles while I'm in here for the folks more committed to keeping the 4x140 bolt pattern than I am. In combination with the coilovers & camber plate adapters this may end up being a serviceable way to get new suspension on these old cars. 

[moosens]

Awesome. Don’t think nobody’s watching. I’m just too busy with other stuff and my similar project is a good year away or more. 
 

Thanks for posting all the pics and details.