The Journey of Linda and Friends - the M20b31 Lives

[wworm]

lol
Well please keep us posted on what the rotors end up being. Hopefully they're not custom. You might be better off using stock rotors from something bmw and making custom brackets..maybe idk. Thickness is going to be tricky to work around. I couldn't find any OEM rotors that are 27mm thicc in de back

[AWDBOB]

lol
Well please keep us posted on what the rotors end up being. Hopefully they're not custom. You might be better off using stock rotors from something bmw and making custom brackets..maybe idk. Thickness is going to be tricky to work around. I couldn't find any OEM rotors that are 27mm thicc in de back

I certainly will!

Ill likely just clean these rotors up and hope they aren't warped for now. They're so close to E36M3 sized rotors, just with a different offset (or so I think). Full custom rotors are way more than I'm willing to spend.

The other option is to get E30M3 hats from I.E. and hope the offsets are correct, then get blanks made (much cheaper than a full custom rotor).

Edit: I'm so convinced they're E36M3 rotors I'm going to buy some locally. I've looked at hundreds of photos at this point and they're identical. And I'm pretty sure the rear thickness was wrong on the listing, as the rears look significantly thinner than what I have written down. I will measure with a caliper tonight.

[wworm]

I'd be happy to swing by a junkyard and take some measurements if need be.

[AWDBOB]

I'd be happy to swing by a junkyard and take some measurements if need be.

I appreciate that- I think I'm just going to bring the rotors into an auto parts store to see if they're the same or not. I'm hoping the kit doesn't require a spacer for the hub to fit the different offset of the E36 rotor.

[kid8]

Trans mounts

IMG_2321 by Bobbie Morrone, on Flickr

[/url]IMG_2338 by Bobbie Morrone, on Flickr

Nice work man, keep it going!

I don't know if I'm wrong or not, but I was always under the impression the mounting cups went on top to prevent fluid from getting on the rubber mounts if it were to ever leak. You may want to look into that a little more.

Looking forward to more progress.

[AWDBOB]

Nice work man, keep it going!

I don't know if I'm wrong or not, but I was always under the impression the mounting cups went on top to prevent fluid from getting on the rubber mounts if it were to ever leak. You may want to look into that a little more.

Looking forward to more progress.

Thanks man!

Their functional purpose (in my mind) was for load distribution, so with that in mind plus the mounting locator points I stuck them down bottom.

Realistically, I'd put them wherever there will be less NHV so if it's pretty bad the way they are now I may try them up top!

[AWDBOB]

Went to a local swap meet today and it had me itching to build an M20. There was a local 3L car there with ITBs and another 3L on the way. I need a 288 cam, itbs and a 3.1L in my life, but I don't know if I could spend all that coin for 200whp haha.

Anyway, the car is nearing completion. I wired up the electric pusher fan to the stock harness, finished deleting my secondary thermostat with fresh heater hoses, finished my intake setup, made a bracket to mount the AFM, finished mounting my relays, threw on belts and removed the cruise control unit from the plug under the dash until I can figure out a mounting location for it.

The hot air intake setup is definitely temporary, but I think it'll be fine to use until I get this car running on a MAF.

Mounting the fan to the radiator proved to be an annoyance, as the bolts were hitting the radiator support in every configuration, so it took a little while to get it right. Once I get bushings for the bottom of the M42 radiator I can bolt in the cooling system once and for all and get it bled. I also ordered a coolant level sensor and will have to extend the wiring for that down to the bottom of the rad when that comes in.

I also have to put a grommet on the engine harness for the firewall, but it's a pain in the ass so I continue to put it off. I also need to put on my ABS sensors and my front brake light sensor, but those can wait.

Stage 1.5 chip for M50 injectors from SSSquid.

IMG_2341 by Bobbie Morrone, on Flickr




I tried to do a clean install and use nylon spacers but it didn't clear the rad support unfortunately.

IMG_2364 by Bobbie Morrone, on Flickr



This way didn't clear either.

IMG_2365 by Bobbie Morrone, on Flickr




This was the final solution.

IMG_2374 by Bobbie Morrone, on Flickr
IMG_2366 by Bobbie Morrone, on Flickr



Fan wiring

IMG_2367 by Bobbie Morrone, on Flickr
IMG_2368 by Bobbie Morrone, on Flickr



And the right side of the bay all tidied up. I'm happy with the AFM bracket and relay location. I love how simple/clean this engine bay is looking. In the first shot you can also see where I tucked away the coil to.

IMG_2372 by Bobbie Morrone, on Flickr
IMG_2373 by Bobbie Morrone, on Flickr

[wworm]

I'm still amazed at how much bigger an m20 can get. I wish there was that much development for m30s, because timing chains are cool...

m20b30 also sounds pretty damn rad. And so to itb's. Looking good man, cant wait to hear this fire up.

[AWDBOB]

I'm still amazed at how much bigger an m20 can get. I wish there was that much development for m30s, because timing chains are cool...

m20b30 also sounds pretty damn rad. And so to itb's. Looking good man, cant wait to hear this fire up.

Absolutely- the cool thing about everything I'm doing now with this setup is that I'm getting all of the annoying stuff out of the way for the M20, so if I were to build a motor, it would be 1-2-3 to get it swapped in since the exhaust, cooling, brakes, etc will all be done.

And I agree on the M30 thought- it seems there is little M30 aftermarket support because once you build one you're in S38 $$ territory. But S38s are a pain to keep on the road, so the M30 still has it's single cam appeal (and this year it's been around for 50 years). But it's heavy, and doesn't really make much more hp (but is great for low end grunt).

What really gets me is that there doesn't seem to be a good power to $$ ratio for any E30 swap or build. There's always a significant compromise. Turbos are high maintenance (I've owned plenty of turbo cars and don't want another). M/S52 doesn't make enough power to justify the cost. V8 swaps interfere too much with braking characteristics, etc etc.

The only swap or build that actually seems worth it is an S54. Great sound, power, still can use a 944 booster with modified airbox, etc. But it all comes at a steep price tag to get it done right.

The lesson here: shut up and enjoy the glorious single cam straight 6 engine sounds to forget we're making 150hp.

[stonea]

Shut up and enjoy the glorious single cam straight 6 engine sounds to forget we're making 150hp.

I agree, except that last part... thats why I'm going M30 :devil:

[AWDBOB]

I agree, except that last part... thats why I'm going M30 :devil:

I support your choice! I wish the M30 didn't use a different trans. It is a plus though that you can just plug your M20 engine harness up and go.

The M30 has my curiosity though because you've already got displacement and a timing chain over an M20.

As far as I know, M30 heads have little to be gained on the exhaust side from head porting, but adding a bigger intake valve and modifying the seat can help things flow quite a bit better. That's what Hartge and Alpina did AFAIK.

With an M30 you already have the displacement on your side and stroking them further is insanely expensive, which makes me wonder how an M30 would respond to a nice set of high compression pistons on a 1mm overbore with some nice head work, a 284 cam, long tubes and ITBs (RHD is almost done their M30 ITB kit). I also don't know about M30 piston dome and if it's as important as it is on an M20 to combat knock and whatnot.

It may be worth the initial investment up front for the M30 to go that route over stroking an M20 and performing the same mods to that.

Hmmmmm

Edit: not nearly as exciting as I had imagined:

https://www.bimmerforums.com/forum/showthread.php?732622-M30-NA-Project-3-6L-Stroker-Engine

[wworm]

Yeah. I think sticking with the m20 is a better idea overall simply for cost and balance reasons. Its made for the chassis so there isn't a whole lot of compromise. I also think single cam straight 6's are one of the best sounding engines ever. Not a huge fan of 24v engine sounds tbh...

I still stand with you on a windsor 5L being a really great choice for this. I just wish the whole brake booster thing wasnt such a pita.

[rturbo 930]

I also think single cam straight 6's are one of the best sounding engines ever. Not a huge fan of 24v engine sounds tbh...

M20s are among the best sounding inline sixes there are, M/S50/52s are among the worst.

[stonea]

Honestly the biggest reason I'm going M30 is because I love the sound of a BMW SOHC I6, but I already want to do a M20 stroker on my ix and want to do something different on my 325i. I was worried about finding the trans, but I was extremely lucky and found one right away and for a decent price. Honestly I think it was the first M30 piece I bought. The only bad thing is it seems like its almost impossible to build a NA M30 without draining your bank account. Luckily for me I have a spare M106 Turbo sitting in my garage :devil:

[AWDBOB]

Yeah. I think sticking with the m20 is a better idea overall simply for cost and balance reasons. Its made for the chassis so there isn't a whole lot of compromise. I also think single cam straight 6's are one of the best sounding engines ever. Not a huge fan of 24v engine sounds tbh...

I still stand with you on a windsor 5L being a really great choice for this. I just wish the whole brake booster thing wasnt such a pita.

M20s are among the best sounding inline sixes there are, M/S50/52s are among the worst.

Agreed on all of that. I think once I get rolling I'll be happy with this thing for a little while. I've heard 24v cars that sound good but most sound raspy and ricey. M20s/M30s sound glorious though.

And 5.0 is the master plan! I have my doubts though. I think I'll end up staying with an M20 in the long haul just so I don't have to change everything I just got done working out the right way. Sometimes simplicity in a well put together chassis is better than power. Brake booster is always a royal pain, and you can't forget the headers that you have to install backwards and somehow route around everything and turn back around under the car.

Honestly the biggest reason I'm going M30 is because I love the sound of a BMW SOHC I6, but I already want to do a M20 stroker on my ix and want to do something different on my 325i. I was worried about finding the trans, but I was extremely lucky and found one right away and for a decent price. Honestly I think it was the first M30 piece I bought. The only bad thing is it seems like its almost impossible to build a NA M30 without draining your bank account. Luckily for me I have a spare M106 Turbo sitting in my garage :devil:

That sounds like a great plan! M30s are made for boost. I think having the balance of a stroked M20 and boosted M30 in the fleet would be an awesome combination of cars to own.

As far as an M30 trans goes, there are two available locally, I just have a nice G260 that's freshie fresh that I don't want to give up.


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Just for fun, here's a cold startup video! Don't mind my whistling towards the end. I'm happy with the response of the car at idle. This is with everything hooked up sensor-wise other than an 02 sensor, running alternator and PS belts. It's very snappy. Running open headers. The head is extremely quiet for an M20.

I believe you'll have to click the picture and it'll take you to the video.


Untitled by Bobbie Morrone, on Flickr