(Yet another) M42 top end refresh and engine reseal (mid-2021)

[econti]

M10 is good for a 'classic' car but honestly M42s feel way better to actually drive. Plus it's an easy 5 speed conversion rather than trying to find a m10 5 speed.

[mjweimer]

Totally get it. Fun choices too. It's all about time and money + what you want to do with it.

I'm a fan of the original M10 + maybe side drafts. Such a simple, durable motor and a ton of fun in that chassis.

Exactly and yes, the M10 is a great little engine, robust and will run for eternity when maintained (and even when not). He's run the M10 for years and also has a M10 in his '68 so he's leaning hard for swapping the '73. It helps that he's had a complete low mileage M42 engine/harness/trans for years now...but he's worried about messing with the character of the car.

I keep up with the '02 crowd via the FAQ but rarely post, that group would want to scavenge my E21 for parts....ha ha ha.

[jsnppp]

It's a '73 base 2002 that is currently running a M10 with CIS from a late E21. It was rebuilt/ lightly restored many years ago now and the big decision is what to do....keep the M10 and rebuild with carb or go M42 swap, repaint the car and replace all the tired trim or leave it alone, etc., etc. Good news is that it is basically rust free and has few other issues. Ultimately it's a discussion of how deep to dive.

Totally get it. Fun choices too. It's all about time and money + what you want to do with it.

I'm a fan of the original M10 + maybe side drafts. Such a simple, durable motor and a ton of fun in that chassis.

[mjweimer]

It's a '73 base 2002 that is currently running a M10 with CIS from a late E21. It was rebuilt/ lightly restored many years ago now and the big decision is what to do....keep the M10 and rebuild with carb or go M42 swap, repaint the car and replace all the tired trim or leave it alone, etc., etc. Good news is that it is basically rust free and has few other issues. Ultimately it's a discussion of how deep to dive.

[jsnppp]

Great thread! Your documentation of the work is excellent and I've been referencing it often as I discuss the pluses and minuses of M42 swapping a 2002 with my brother. Good to read it will be soon on the ground and ready to go for a spin, your daughter must be getting pumped.

Awesome! Really glad to hear it. I have some updates to do to the first page, missing some photos and recommendations..

What 2002? I've been part of the 02 community for 30 ish years... more recently into e30s (late to the party).

[mjweimer]

Great thread! Your documentation of the work is excellent and I've been referencing it often as I discuss the pluses and minuses of M42 swapping a 2002 with my brother. Good to read it will be soon on the ground and ready to go for a spin, your daughter must be getting pumped.

[jsnppp]

Chugging through the endless wires and pipes while I figure out how the front nose goes back on! Think I have it figured out. Had to shift the muffler a bit and then installed the power steering pump belt. Was pleased to see the new power steering rack doesn't leak (yet!) and it appears to work fine. I also resealed the AC compressor (actually a fun job) and reinstalled. Super clean. With the new parallel flow condenser I'm excited to see how the AC works (later, now now).

It's close to being dropped back on all four wheels and driven around the block.

[jsnppp]

Awesome! It sounds like a successful conclusion to a long adventure. Big props to you for taking the time and making the effort to re-do the head install when you realized that the washers were missing, and all of the other meticulousness. With any luck, your daughter will have learned a lot and be yet another capable E30 owner!

Thanks! Your posts/insights over the years really made a difference to us. Thanks for taking the time to write things down and chime in with experiences. Safe to say it would not have been this "easy" without you.

Hopefully there is another 100k miles in it (221k on the clock, but I have zero history on it other than it had a ton of oil all over it and every hose was cracked).

[jsnppp]

Always good to hear another E30 brother (and daughter) celebrate a 'win' after some major mechanical work.

It's been a fun journey. Took much longer than I planned, but partly because I have several projects open at once. Also, I never knew what I needed so I had to keep ordering things...

We bought the car from California in early 2021. I trusted the seller a bit too much but all in all it's solid and all there. The white/black was what we wanted.

Not quite done yet but definitely a massive milestone... Daughter enjoys wrenching, I do the heavy/dangerous stuff but she is always there to chip in. Ideally we get the car moving for her to drive this semester. We've done just about everything but the body work..

[jsnppp]

Last night r3v wasn't available to me. Whether a local connectivity issue or what, not sure...

Also, each time I try adding videos to my original post it trashes my photo links. So, I'm redoing it (for the 4th time) and just posting videos here..

First start - very clattery

After a few runs and it's much quieter

Here is a cold start video from yesterday morning. Interior of the car looks much worse than it is. I have the cluster out because I'm waiting on new SI batteries..

[bmwman91]

Awesome! It sounds like a successful conclusion to a long adventure. Big props to you for taking the time and making the effort to re-do the head install when you realized that the washers were missing, and all of the other meticulousness. With any luck, your daughter will have learned a lot and be yet another capable E30 owner!

[Tzantushka]

It is idling now. Perfect 850.

I took out the ICV and cleaned it, let it soak about an hour and shook it around with cleaner in it. Installed it with arrow "up". I also went around and lightly tightened the nuts holding the intake manifold on. None were loose but all allowed me a slight turn.

Super cool. It's quiet now too. Ok, when I rev it and let off I hear a slight rattle, but it's not internal engine, sounds more like an exhaust shroud or something. There are bolts everywhere and stuff loose so I'm not concerned...

Now need to finish putting the nose back on it, rebuild the AC compressor and install it, fill the power steering reservoir and get it back on all 4 wheels. How cool is that!

Videos next.

Always good to hear another E30 brother (and daughter) celebrate a 'win' after some major mechanical work.

[jsnppp]

The arrow indicates air flow direction, so yes pointing to the manifold is correct. If it is properly clean, you should be able to shake it (rapidly rotating it along its axis) by hand and hear the little door banging around on its stop. It usually needs to be pretty seriously gummed-up to get stuck open, but it is certainly not unheard of!

I had decent luck cleaning mine by running some 99% isopropyl alcohol through it and rapidly connecting/disconnecting it to a 12V battery with alligator clips. Try not to submerge the whole thing as the solvent will get down into the lower area with the coils and stuff. It should not hurt it, but greasy stuff can work its way in with the solvent. If you want to make sure things are dried out, you can bake the thing at 175-200F for a couple of hours when done (there's nothing my wife loves more than coming home to car parts in the oven lol).

Ha, I missed this post.. I luckily didn't submerge it, but did shake the fluid around.. I didn't try the rotation test, but the flap door was able to be moved easily with a small screwdriver.

Checking the plug - no opens that I can see:


How it was installed (arrow up)


Dirty inside


I didn't take an after photo. Not sure if it needed cleaning, but at least its shiny inside now.

Regardless, it's idling at 850 ish, nice and steady!

[jsnppp]

It is idling now. Perfect 850.

I took out the ICV and cleaned it, let it soak about an hour and shook it around with cleaner in it. Installed it with arrow "up". I also went around and lightly tightened the nuts holding the intake manifold on. None were loose but all allowed me a slight turn.

Super cool. It's quiet now too. Ok, when I rev it and let off I hear a slight rattle, but it's not internal engine, sounds more like an exhaust shroud or something. There are bolts everywhere and stuff loose so I'm not concerned...

Now need to finish putting the nose back on it, rebuild the AC compressor and install it, fill the power steering reservoir and get it back on all 4 wheels. How cool is that!

Videos next.

[bmwman91]

The arrow indicates air flow direction, so yes pointing to the manifold is correct. If it is properly clean, you should be able to shake it (rapidly rotating it along its axis) by hand and hear the little door banging around on its stop. It usually needs to be pretty seriously gummed-up to get stuck open, but it is certainly not unheard of!

I had decent luck cleaning mine by running some 99% isopropyl alcohol through it and rapidly connecting/disconnecting it to a 12V battery with alligator clips. Try not to submerge the whole thing as the solvent will get down into the lower area with the coils and stuff. It should not hurt it, but greasy stuff can work its way in with the solvent. If you want to make sure things are dried out, you can bake the thing at 175-200F for a couple of hours when done (there's nothing my wife loves more than coming home to car parts in the oven lol).