[dobu01]

My long-term project mk3.5 Cabrio is finally getting a VR6. I've known I wanted to do this swap for ages and have been researching/planning how to do it for at least 4 or 5 years. I had the absolutely perfect donor car come along, a very lightly crashed 2 owner 1997 Jetta GLX 5 speed in astoundingly good mechanical condition with just 78k miles. So I decided to make the leap.

I figured this thread would be a good place to kinda narrate the build and show what I'm doing to anyone who's interested. I have the build pretty well roadmapped but definitely would welcome any insight you guys have about what I'm doing. And I know I'm gonna have some questions on technicals and best practices. This will be the biggest wrenching endeavor I've ever taken on.

Let's start at the VR6 roadmap. It's staying naturally aspirated. For now . While the engine's out of the bay I'll do some regular maintenance items. I'll most likely do mkiv head gasket, replace valve cover gasket, new oil pan, timing chains, engine mounts. Previous owner clearly did very recent sparkplugs, rear main seal, and a new clutch so that's a win. I'll probably do replacement coolant lines too. In terms of performance upgrade stuff on engine- looking at doing 268 cams, techtonics/magnaflow catback and leaning towards techtonics on chip since they seem to have a bunch of tunes that seem to mirror my build plan. But I'm still researching.

Possibly the most striking part of this build is that I'm going very minimalist. On the Cabrio 2.0 ABA I had previously done an AC and power steering delete, those items will stay deleted with the VR6. The plan is also to nuke all of the EVAP/SAI/PCV stuff. A) The simpler this build is the better, from both a mechanical and electrical perspective. And I love a clean bay. B) This is legal in my state and C) from an ethical perspective- the Cabrio is not a daily driver, it'll see MAYBE a couple hundred miles per year tops and so I'm not amazingly worried about my carbon footprint.

Next post will be days 1 and 2 of wrenching but in the meantime- let's take a look at the donor and patient ready for action:

 

[dobu01]

Day 1 and 2 of wrenching/disassembly went well. Had a fun moment where I had everything prepped in the garage and I was like "Ok. So something has to be the first bolt to start off." 😂 Made the most sense to me to start with disassembling the ABA out of the Cabrio, mostly because if I screwed something up the stakes were lower and I figured that with the architecture being so similar to the VR6 it'd be a good practice round. Grille and bumper cover off first. Drained coolant. Headlights out. Pulled front clip off modularly, as such-

For me, the gameplan is to reuse the VR6 radiator in the Cabrio's radiator support since the donor Jetta's radiator support was collision damaged and ABA/AAA radiators are different in terms of inlet/outlet. Not sure exactly if the VR6 fans are reusable or damaged, or if the ABA fans are the same part; that'll be solved another day when I can compare em side by side. Next was pulling off the ABA air intake and associated electrical, disconnecting the throttle cable, pulling electrical from starter and alternator and disconnecting any other visible electrical connectors. Pretty cool how the design works; most of the wiring harness is concentrated to the drivers side fender and anything that goes elsewhere in the bay from there is pretty obvious.

After that, disconnected shifter linkage, the weight with the cotter pins and the actual shift linkage with the ball/socket joints. Clutch cable disconnected after that, which I would have ideally had 3 hands for. Pulled off fuel lines, disconnected the downpipe from the exhaust. Coolant lines off the heater core and the ball, distributor wire off the ignition coil, all electrical off the transmission. Next was disconnecting the stuff that's getting deleted; the EVAP, PCV, SAI stuff. Basically, I separated all of those components from the engine and pulled off their electrical connectors, and then went about gutting the actual components out. My biggest question-mark honestly is the EVAP stuff; I'm left with two white hard plastic lines under a heat shield which I'm not sure I should plug or vent to atmosphere. I'll be hitting the search function, but feel free to chime in if you have insight. And obviously, I disconnected the axles.

Overall, I was able to get to the point were I could verify the ONLY connections between the Cabrio chassis and ABA/020 trans was literally just the mounts. If you're ever thinking about doing this, that's the point in disassembly you want to get to, and exactly the point I'll get to again when it comes to separating the VR6 from the donor Jetta. These two pictures don't totally do it justice, but this the state of the ABA/020 only being connected by mounts-

and

I'll have further updates tomorrow.