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1991 318is transmission m20


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I have done lots of research on which transmission would be easiest for me to use for the m20 swap. The 323i is the best but I have had no luck finding one (so far!)

The 1991 318is tranny works and fits with the m42 swap in a 2002.

That means that it would fit without any cutting of the tunnel for an m20 swap?

If anyone can help me with this I will start getting all my parts.

This is the only thing holding me back.


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Dave Varco (Aardvarc racing) had a 323 tranny on eBay recently. Give him a try... He's a nice guy and a reputable seller FWIW...

I'm sure he'd sell the tranny without going through ebay too if you just give him a call. He's in San Diego area too, so maybe roadtrip to pick it up and save some shipping $?


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Yes the 318i M42 240 box will fit the tunnel but you loose the mechanical speedo' drive of the 245 box and fabbing' the crossmember will be much harder. The next question I would have I do not have the answer to though is, Would the tail housing of the '83 320i 240 trans swap onto the later M42 240 version??? THAT is the question I would like to see an answer to!

I've got a 323 4-speed for $250 till you find the money to swap the bell housing onto a 4cyl 245. Also have a 323 5-speed, but that one costs much more...


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That should work with a little fabrication. As I understand it, the M42 and the M20 share a bellhousing pattern and both use the Getrag 260. Jakeb has found success using this trans in an 02 with the M42 engine. See HERE.

You'll have to build a rear transmission mounting bracket similar to Jake's (or buy one from him):


You'll also have to go with an electronic speedometer. many steer clear of an electronic speedometer, but if you're already doing that much modification.....

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aaron, I'm going to call him up and see what he offers price wise!

Tom Jones, Im going to email you about the 5 speed.

Thats a good question. If it did then you wouldnt need an electric speedo. (if the 83 320i 240 trail housing could swap on the later m42 240).

Clay, I have talked to him a couple days ago. I havent seen this picture though so I will see if hes willing to make me a bracket. Thanks!!

Thanks for the help everyone. Really appreciate it!

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You'll have to build a rear transmission mounting bracket similar to Jake's (or buy one from him):


You don't want your transmission bracket like that, the exhaust has to go under it so you'll have no ground clearance left.

Drove like that for 1.5-2 years and finally got rid of it a few weeks ago.

I just made something with 2 of these and a new homemade bracket that stays closer to the tranny.

Gave me 1-2 inches of extra ground clearance (which is enough) and it only took 1 or 2 hours.

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I'm looking to do the opposite swap. I have a 323i transmission I want to use with a m42 in my 2002. Does anyone know the angle for the m20 motor? From what I understand, the m10 and m42 are both mounted at 30 degrees but I can't find any info on the m20's angle. This will tell me how much the transmission angle will be off.

TIA, Steve

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Steve, the M42 mounts at a steeper angle than the M10. I've got the E21 323i transmission behind mine. It's dead easy to compensate for the difference. E-mail me if you've got any questions. Jake is always willing to help '02ers as well. FWIW Ben Thongsai says that the early and late Getrag 240's can be hybridized as Tom suggested to provide a mechanical speedo drive.

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That sounds like a smart idea 4x2. Do you think that same mount you have would work to hold the 240 transmission for my m20 swap? Or it wouldn't work the same because the engine is at a dif angle than a m42. If you dont mind what is your email?



E-mail is in my profile.

My transmission is a 240, but on a M10, but I don't think it would really matter if it sits at a slightly different angle, you just have to modify the mount a bit.

I'll try to remember to take a picture the next time I have it on stands.

But since that might take (quite) a while, long live ms paint ;-)


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