M42 west coast meet and cruise?? Anyone interested?

[allan633]

My god I love this car! It's been converted for a while now. Just went out for a cruise this morning after doing a few small things to it. Amazing!
But I've never driven or even seen another m42 converted E21 running. Might be fun to see how many different ways there are to "skin a cat"
Here are some pics. The first one is the truck scale weight of the front of the car with me in it. The second is the rear of the car, again with me in the driver's seat. I'm 230 pounds, there's the battery, an amp and sub in the trunk. Oh, and there are two brake calipers in there as well, forgot to take them out after the junkyard. Pretty good balance!
The third picture is one of my favorite sights on this car. Look at the amount of Real Estate in front of the engine!
I'm getting ready to put an m42 in the track car, this time using the 245 driveshaft and shifter parts with a 242 4-speed. That'll move the engine back another inch and a half, still using all stock parts! And the oil pan will still clear the subframe by a mile. Probably can't say the same for the head/firewall clearance. Nothing a little sawzall action won't fix though!




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[WantingAfunE21]

I'm getting ready to put an m42 in the track car using the 245 driveshaft with a 242 4-speed.

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This is genius!

[allan633]

This is genius!

I think it's the easiest, cheapest way to do it. No need to screw around with the E30 Drive Shaft center support bearing and most of the location problems disappear​.

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[Somjuan]

Very cool! I don't have an m42 swap, but I'd like to join in and see a few

[Tom D]

put an m42 in the track car, using the 245 driveshaft and shifter with a 242 4-speed.

this won't work allan, the G242 has a different bell housing pattern and doesn't mate with the M42.

you could use the G240 with a G242/245 driveshaft, but these are fixed length shafts and it forces an exact placement of the engine. i had contemplated doing just that on my first build, but quickly dismissed it for the E30 adjustable shaft. theres also shaft angles to consider and having a new center bearing mount installed allows you to control the angles easier.

[Tom D]

as far back as you can get without cutting the bulkhead using the E30's shaft.


and as low as you can get


and still have room to run the factory steering dampener


and one just for the fun of it.

[allan633]

Hey Tom!

No, using a stock e21 driveshaft in any of the lengths available, with the corresponding shifter parts and rear mount means all that location stuff is oe, boltup and in stock position. No shaft angles to consider, it's all stock! It locates the fore-aft position of the engine depending on which driveshaft you choose, no more or less end strain than stock would have been. And no csb hanger to relocate. I just bolted all that stock stuff up with the engine hanging from a bar across the front end, set the left-right and up-down position of the engine to stock using the center line of the crank and made the subframe modifications as needed. Been working great on my street car for 10k miles so far. That's what made the engine setback so easy.

The new setup with that super short/light weight 4 speed and the short 245 driveshaft will put that engine way back using only factory parts. I'm not using a rear battery anymore and the car has been lightened in the rear, maybe too much, so I'll really be able to use that extra setback. I can't wait to see how it balances front to rear!

The 242 I'm using is from an m20 car (maybe it's not called a 242? Looks about the same) so it'll bolt up to the m42. It's worth nothing because no one is looking for a 4 speed! It already has a three bolt flange on it. My street m42 car has the 240 Frankenstein conversion, a bunch shorter than a 245, about 2 inches. This tran is at least 1.5 inches shorter than the 240 and about 20-30 lbs lighter. I'll never need 5th anyhow with the chipped m42 able to rev close to 7k. I'm gonna mock the whole thing up on a junker to see what else needs to happen for clearance and then make a "kit" so I can just bolt the whole assembly into the track car and plug it in. The important thing is that it looks like the oil pan will clear the subframe. Should be very fun!

This is why I'd like to see some other converted cars in person. There are probably as many little detail differences as there are cars!

By the way, I have 2 extra e30 sump setups if anyone is looking to convert an e36 m42. If you need one, figure out what they're worth on ebay and I'll beat that price by 10% plus shipping. Tom, you'd know, what's a fair price for that stuff?

[Tom D]

yes you are right, i forgot about the M20's G242. keep I'm mind though that the M20 sits at a different angle then the M42.

- - - Updated - - -

where did you find a G242? must have been out of an E12?

[Tom D]

another food for thought. bmw set the engines in the E21 pretty high (in comparison to my swap above). if you intend to set the M42 low but still use the stock driveline mounts you'll probably need to shim them down to keep the shaft angles right.

below is a photo of the car we were working on when you stopped by. we're using a M10 G240, M42 bell housing and the stock E21 G240 transmission crossmember. the engine is sitting as low as we can get it, take note of how low we shimmed the trans mount.


E30 shaft and new bearing mount


and final shaft angles, pretty near perfect.

[allan633]

I'm thinking that if I have the crank centerline right, like an m10 car, it should be great. I'll have to check to see if an m20 car is much different in that way. Never thought about it!

I never noticed how you set the assembly lower like that too. I can see why. I had mine about like that at first but I kept worrying about the oil pan. I'd tense up every time I straddled a pebble! Now it's at stock height and the pan is almost level with the bottom of the subframe, maybe a quarter inch lower. I'm sure I've given up something in cg but I can't tell and I'm not worrying as much so I guess its okay. Maybe the track car's assembly should be lower... Something to think about, thanks!

The 4 speed trans came with my May of 1980 grey market Baur 323i. It was a parts car for about 15 years so it got pretty picked over. The car lost a timing belt in SLO in 1999 and it was all down hill from there! The car is an interesting "cusp" kind of thing. It has a mix of original looking early and late parts on it so who knows?

[Tom D]

i like the way you did the top radiator mount. do you have a full engine bay photo?

[Tom D]

i use two of the left side E30 lower radiator mounts (or maybe the right) and slot them into the frame rails just like the factory, makes for a clean install. but i never did figure out a good way to mount the top, i'll be copying you in the future.

[allan633]

Looks Factory! There it is again. There must be a million good ways to do the details on this conversion. It would be fun to see some variations in person.

I used the stock radiator stand-offs extended a bit with end pads added to fit directly below the radiator core. Not sure if you can see this well enough...

The radiator ended up well back from the core support but by using the stock e30 upper support part but what the hell, plenty of room there!




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[tlapham]

I would love to do a drive, but I'm shipping out tomorrow, won't be back on the west coast till mid- August at the earliest... My babies are tucked in for a long summer...
DSC_0499.jpgDSC_0500.jpg

[allan633]

I would love to do a drive, but I'm shipping out tomorrow, won't be back on the west coast till mid- August at the earliest... My babies are tucked in for a long summer...
DSC_0499.jpgDSC_0500.jpg

Got time to post some m42 porn before you go? 😁 Have a good trip. Maybe we'll do that cruise after you get back.

Here's my engine compartment.

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[allan633]

Got time to post some m42 porn before you go? 😁 Have a good trip. Maybe we'll do that cruise after you get back.

Here's my engine compartment.

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Well, hell, this might just work!

New project mock up:

M42 with (very short) 4 speed trans coupled with short 245 drive shaft/shifter parts allows the engine to move back another 1.5 inches compared to the 240 trans.

Looks like the front edge of the subframe will be right under the timing chain while not needing to move the heater blower!

Sheee-it, this could be good!

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[WantingAfunE21]

Wow!

[bassboy3313]

Thats awesome Allan!!!

[allan633]

Thanks!

I'm thinking about losing the heater system because it's just a track car. That would make the perfect place for the wiring box and cut another x lbs. off of the car....

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[Somjuan]

Witchcraft!

[allan633]

Witchcraft!

It just doesn't get much better!

Looks like it was designed this way.

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[jaredmac11]

Very cool! Love these pictures.

Really curious on that getrag 242 for the m20.. were these euro cars only? Off the 323i?

[Layne]

Very cool! Love these pictures. Really curious on that getrag 242 for the m20.. were these euro cars only? Off the 323i?

323i and 320/6, euro only. I have one if you're interested.

[jaredmac11]

323i and 320/6, euro only. I have one if you're interested.

Sent you a PM, Layne.

Has anyone just had a shop shorten a driveshaft to spec? This is where I think I am.. it'd be nice not to have to fuss with even more fabrication

[allan633]

Sent you a PM, Layne.

Has anyone just had a shop shorten a driveshaft to spec? This is where I think I am.. it'd be nice not to have to fuss with even more fabrication

Hey JaredMac, I'm just at the point of messing with driveshaft lengths too. But with so many different lengths of E21 drive shafts there's always one that's pretty close. Maybe you don't have to have one modified. Don't forget the automatic driveshaft, it's right in between the 245 and 240 drive shafts in length. If you need measurements, let me know.

Layne, that sounds right. This transmission came from a pre 80 323. Maybe also in e12s?

Here's a weird one. It's that 242 transmission bolted to the m42 with the m42 level and in position. Look at this damn thing leaning 15-20° to the right! I don't think it'll be a problem but it is kind of weird.

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