Jump to content

M42 is the new black



Early last year 2018, a friend, Rob swapped a m20 into his 318 Convertible and he asked me if I'd want his m42. I'd been interested in this swap for a while so I said absolutely. I was pretty intimidated no matter how many writeups saying it's easy I read. And thanks to all those who have done writeups before me. They were all super helpful.


Big shoutout to Jakeb for infinite and timely help along the way to my millions of questions he answered amazingly quickly considering how busy I can imagine he is. Special thanks to my buddies Rob  and Austen


For full disclosure on my car experience. I have always been a figure-it-outer but as far as cars go I have changed oil myself on nearly all my cars, I've replaced a catalytic converter, changed rotors and pads (with help) but any major engine work I've always gone to a shop. A lot of this felt way over my head but breaking it up into digestible pieces made it doable. 


Pics below show where I started and the progress. Rob and Austen dropped off the m42 one cold February 2018 afternoon and we set it up on a stand. It was pretty filthy and crusty. I felt if I was doing this I didn't want to just drop in a dirty engine. I also wanted to have a better understanding of all the components and use this all as a learning experience, so hopefully when something fails I'll be able to fix it myself. I wanted to pull apart and see firsthand how everything works and goes together, replace anything that didn't look good and replace as many seals as I could. I left the rear timing case housing in place and didn't remove the head. I ended up having to replace all the timing rails, but Blunt thought the sprockets and chain were fine. 








I sent the valve cover and intake pices to a local powder coater to get refinished.













This work took me most of the summer cleaning, painting when I had time. Having never done any of this before I was pretty slow and methodical, doing lots of reading before doing anything. I was also tracking down all the other parts needed for the swap since Rob just had the engine, driveshaft, flywheel, clutch and computer. So I had to find all the other bits elsewhere - Radiator, transmission, fuel pump, battery cable etc. It was a lot of stuff. I'm hesitant to go through my reciepts and add it all up.


The big day finally came in the fall. Rob came over and we pulled out the m10. This part wasn't that bad having someone experienced like him to help. While the engine was out I figured there was never a better time to clean up the engine bay. I've never really particularly like red cars. The first 02 I recall seeing in person was a Colorado in Vancouver BC and always loved it. I also really liked Inka. I put the 2 to a vote with my wife and 3 year old and Inka won. (I was the lone Colorado vote) My Father in law is a huge Buick guy. I think he was 7 50's Buicks right now, all restored by him. He had offered to paint the car and so he came up and we cleaned up and sprayed the bay Inka. I checked into getting the legit OEM paint and the price was way too high (I think when I priced it out over $1000 for the paint) He had used Nason for all his Buicks and I think in the end paint was about $300. Single stage urethane. The plan then was that he would do body work over the winter while the car is stored at his house and paint it in the Spring. More about that later. 










It seems like i didn't get and shots of the engine going in but here it is in. It came from above with the transmission attached. 





There was still tons to do and I enlisted Austen (@millcitymoto612 on Instagram), who's a super talented full-time mechanic. He currently runs a supercharged m3 in his e30. He and I or just me plugged away at it for about a month. 




I wanted to do the "Mess under the intake" mod and Austen was super helpful here getting everything plumbed up. The wiring was a bit of a mess for a while. I didn't really want to clean it up until all the wiring for everything was done, and there was still things like installing the tach adapter and where exactly I wanted to locate the new fuses and relays so we just cleaned up the best we could and left wires long for the time being. You can see in this pic the new fuse box and relays are near the 02's fuse box. I ended up putting the fuse box wat up front to the left of the 02 relays. I put one of the new relays in the open spot next to the 02 relays and the other new relay was placed near the firewall where the m42s relays are. 




First start 



At the same time I swapped in a e21 LSD I had picked up earlier in the year. It was pretty crusty but cleaned up nicely. Had Ireland send a set of redrilled flanges and got new seals for the flanges as well. When I pulled the 02s diff I found that the mount bushings were shot so had a local shop, Huber Imports near me in Golden Valley press in new ones. Werner Huber and his sons run the shop, they are the nicest people you'll meet and reasonable prices, highly recommended if you're in the Minneapolis area. 


Found a torn CV boot so learned how to fix that too, which was much easier than I thought it would be. Messy, but pretty easy and satisfying.
















Austen had a really cool way, I thought, for shortening the shifter linkage. Maybe this is a common knowledge way to do it but I never read about it anywhere online - I got my measurement the best I could and then cut a section out of the linkage that was very close if not a bit short. Then, since the linkage is basically just a tube I tapped the inside of each side of the now cut tube and used a big corresponding bolt and threaded it all together. Then if theres any adjustment you need to make you just unscrew it a couple turns. Once I was happy with the shifter position I just popped over to the CarX near me and they welded it up. For the carrier I ran into a bit of a snag. I was assuming my 02 carrier would work, just that it would be too long and need to be trimmed down. I was wrong, it was too short, it's the e21 carrier that can be shortened. I didn't really want to wait around for one to come so I instead bolted some flat iron to my 02 carrier to make it work. Looks ugly but it works. I do have an e21 carrier from Jakeb sitting in my garage, just need to put it on. 






One of the parts I realized too late that I was missing was the throttle linkage. This is where all my watching MacGyver in the 80's paid off. The car was basically done and I wanted to get it to the exhaust shop to get welded up so I rigged up this ugly thing. It's a lumber tie leftover from when I built my deck and a bracket from an Ikea shelf. Vroom




Luckily it was only about a mile or so to the exahust shop. The car wasn't running great, I assume because of the lack of the oxygen sensor. Also, I had no idea what the engine temp was doing because my gauge wasn't working yet. The exhaust shop did confirm the engine was staying at operating temperature. Later, After lots of headaches and red herrings I figured out that the sensor I had pulled off the m10 for the temp gauge was not working. Swapped in a new one and the gauge came back to life.


A few other notes. I used the m20 flywheel and clutch with the getrag 240. I don't have a frame of reference for the difference vs the dual mass but the car definitely feels peppy. I didn't really go through the transmission when I got it (came from a junkyyard in Iowa) I probably should have. I was having an impossible time bleeding the clutch and came to find that the slave cylinder was shot. I watched a video about changing the slave when the transmission is in a 318. Looks easy. In the 02 the tranny sits so close to the tunnel and had to use enough socket extensions to reach about 3 ft and I still got bloody knuckles. I also found that the clutch sounds a little buzzy un release. I used a new throwout bearing and new clutch fork and spring clip. 2nd gear is a little tough to go into. 


After it was all running I had about a week to drive the car before it was time to send it to storage at my Father in Laws. I usually drive it there but I was a little nervous to to the 2 hour drive knowing all the kinks weren't worked out yet so I used my AAA to have it towed. 





My father in law spent the winter picking away at the bodywork. When we went there he already had the hood, doors and fenders bondo-ed up. The big bumpers were going to be replaced for early bumpers so he did the appropriate bodywork to prep for that. We also filled in the lower plastic trim holes.












The cold and snow (and salt) lasts forever here in Minnesota so we didn't go down to pick up the car until early May. We went down to Austin, Mn on a saturday and the plan was to do that last bits of work and then I'd drive it back to Minneapolis the next day. We needed to get both windshields back in, install the new door panels, and attach the new early bumpers. On Sunday I thought Mark and I should take a shakedown drive to see how the car was running. About a mile in I noticed the temp gauge get to 3/4. Pulled over and could see coolant under the car. We were still pretty close to home so we limped back. This is where my time pulling that engine apart came in handy. It was hard to see where the leak was coming from but finally found that the hose on the plastic water diverter off the block coming from the heater core had completely popped off. It wasn't the most difficult fix, but the upper intake had to come off. No clamp was in site, so either there I missed putting one on there in the first place or it fell on when the hose came loose. Got it back on with a clamp Mark had laying around and refilled and bled the coolant for probably the 3rd time since putting the m42 in.


The drive home was great. No issues.


Here's a few other pics and notes. I still have a list of things to do. I have HR springs and front sport struts that need to go on. I want new wheels but am undecided what to get. My wipers aren't working (new relay, pulled wiper motor, looks fine) They were starting to work only at random times even before the engine swap. For the tach I first tried the MSD adapter and it just never did anything, Jake said I should try Andrews Autosports and that one worked right away though it seems to read about 500 RPMs low. I'm still trying to find out how to calibrate it. I installed some Squatch pads in the engine bay. They are awesome, highly recommended. For anyone doing the job, I really didn't want to pull the hood so I had started masking non spray areas quickly realizing how much tape and unsure how to get the pad under the torsion bar after spraying without it getting messed up. I pulled all my masking tape, put the pads in place unsprayed under the torsion bar and put a little masking tape to hold the top from folding down. Then I sprayed a bunch of Super 80 into an old frisbee and applied to the hood and pad with a foam brush starting at the bottom and working my way up. Work toward the bottom from the torsion bar and then work up from the torsion bar. Took me all of 20 minutes. Worked great, no adhesive where I didn't want it and didn't have to remove the hood. 


You can see in the first pic here the radiator is zip tied to the nose. I spent a lot of time trying to figure out a nice solution to tieing the radiator in. Metal would be preffered but not having any fab machinery I looked for a durable plastic that could be used. I found a piece of J channel thats intended for installing vinyl soffits at Home Depot. They only had white but black is an orderable option which I think would look better. You can see my white one in the pic with thw squatch pads. I used some expandable rubber grommet fasteners to tie them together. 










Thanks for reading. Again big thanks to everyone who helped me along the way. Really wouldn't have attempted any of this withoug you. My father in law Mark, Austen, Rob, Jakeb and Blunt. 


Shameless plug - I'm a freelance graphic designer in Minneapolis so if any of you need any design help from a fellow 02er let me know. My work - https://lfdept.com  email - [email protected] 















Recommended Comments

Great write up. That's a whole lot of typing.

Talk about some scope creep! (while the motors out might as well paint the bay. While I'm painting might as well do the car...). Title should have been m42 is the new Inka lol.

You mentioned exhaust shop. Was it just to join the two together, or does this require new from the manifold back?

I'm got my eye on a wrecked e30 to do this conversion. Hope it looks as good as yours.

Share this comment

Link to comment
12 hours ago, GoGo Garnet said:

Great write up. That's a whole lot of typing.

Talk about some scope creep! (while the motors out might as well paint the bay. While I'm painting might as well do the car...). Title should have been m42 is the new Inka lol.

You mentioned exhaust shop. Was it just to join the two together, or does this require new from the manifold back?

I'm got my eye on a wrecked e30 to do this conversion. Hope it looks as good as yours.


Thank you. Luckily I didn't go into as much detail as I could have or it would have been much longer. We had been planning to paint the car for a while, the paint looked ok at a glance but there was a lot of rust bubbles starting to come through so we knew it was going to have to be addressed. Yes, I got the m42 kit from Jakeb and he includes a header and a flange. I bought the downpipe Jake recommended and the exahust shop used that to connect to the rest of the factory exhaust. 

  • Like 1

Share this comment

Link to comment
Add a comment...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.