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M20 conversion transmission selection


NullZwei
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Aside from the e21 323 5-speed, will any of the e21 320 5-speed transmissions work with the M20 conversion? If so, are transmissions intended for a 4-cyl engine application adequate for a 6-cyl? If the e21 320 5-speeds will not work, what are some of the other options? From what I've seen, the 323 5-speeds are getting pretty difficult to come by. Sorry if this has been discussed already but my search techniques really suck. Any input re: the transmissions would be greatly appreciated. Also, if anyone could point me in the direction of any M20 conversion discussions/blogs, that would be most helpful too.

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I believe you need the 323 to get the right bell housing bolt pattern. Have you tried aardvark? I think they have some bell housing's and some complete transmissions. If you get the bell housing off a 4 speed euro 323 it can be made to fit with any US 245 transmission, but I believe it requires a bit of machining. That is what is in my car.

As far as links...

Here are a couple generic ones I have collected.

http://bit.ly/alXENz

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Im not at home so do not have links but I'm in the same position as you.

Ardvark has one for 750$? Around that price.

What I want to use is the 318is transmission. If you look at Jakes golf m42 swap for andys he cuts off the little ears on top of it to make it fit the tunnel.

I heard with banging and cutting off those ears it fits. Now you have the problem of the ELECTRICAL speedo and shortning driveshaft etc.

It does bolt on the m20 and work... Most importantly fit.

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Frenchee,

Maybe it's not a big deal to you, but remember that the E36 240 transmission has a different mounting angle than the M20. Basically it means that the whole thing is going to be tilted 10 degrees to the side. It doesn't mean it won't work, just one more thing you need to deal with.

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I wouldn't worry about the speedo drive as I already have a programmable speedometer which I can run off the driveshaft. My biggest concern is an affordable alternative to the e21 323 5-speed. That's why I inquired about the possibility of using an e21 320 5-speed. I already have one of those that was rebuilt by Jim Blanton. I just don't know if it will work with the M20.

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I believe if you look at the mounting flange on the m20 transmission verus the m10 box you will see the difference. The M20 has a flat or straight section that is something like 7 inches long. The corresponding flat section on the m10 is closer to 5 inches so there is no way the m10 box will fit the m20 or vice versa. That being said I have an m20 4 speed for sale. Gezon@aol.com

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I wouldn't worry about the speedo drive as I already have a programmable speedometer which I can run off the driveshaft. My biggest concern is an affordable alternative to the e21 323 5-speed. That's why I inquired about the possibility of using an e21 320 5-speed. I already have one of those that was rebuilt by Jim Blanton. I just don't know if it will work with the M20.

Don't know if they are still available, but if you can buy a 323 5 speed trans case, you can swap the 4 cylinder innards into it.

Since you don't have to worry about a speedometer cable drive, you should be able to just use an E30 6 cylinder 5 speed.

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Frenchee,

Maybe it's not a big deal to you, but remember that the E36 240 transmission has a different mounting angle than the M20. Basically it means that the whole thing is going to be tilted 10 degrees to the side. It doesn't mean it won't work, just one more thing you need to deal with.

Not e36, e30. Yes, it does have the 10 degree angle, but it fits, and it fits well.

Edit: Technically, its both the e30 and e36.

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Frenchee,

Maybe it's not a big deal to you, but remember that the E36 240 transmission has a different mounting angle than the M20. Basically it means that the whole thing is going to be tilted 10 degrees to the side. It doesn't mean it won't work, just one more thing you need to deal with.

Not e36, e30. Yes, it does have the 10 degree angle, but it fits, and it fits well.

Edit: Technically, its both the e30 and e36.

Scott, so you actually did get it to fit? You cut off the ears etc right. I think it also depends on your mounts. Anymore progress? you get the fuel lines in and fuel pumps? What radiator you using?

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owning an E36 318, that transmission's effectively a tall- ratio non- od 5- speed.

5th's a 1:1 straight thru. So you might want to regear a diff to the 3.45

that comes with it, too...

Because, also owning an E30, that engine makes gobs of torque for

a 325. In a 2002, it's going to want to lope, not scream....

t

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I wouldn't worry about the speedo drive as I already have a programmable speedometer which I can run off the driveshaft. My biggest concern is an affordable alternative to the e21 323 5-speed. That's why I inquired about the possibility of using an e21 320 5-speed. I already have one of those that was rebuilt by Jim Blanton. I just don't know if it will work with the M20.

Get the E30 318is 5-speed, the 5-speeds with a mechanical speedo are ridiculously expensive and you'll save a lot of money if you don't need it.

Or try to source a E30 320 5-speed, it's a 240 as well.

Might be a bit harder find in the US though.

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I wouldn't worry about the speedo drive as I already have a programmable speedometer which I can run off the driveshaft. My biggest concern is an affordable alternative to the e21 323 5-speed. That's why I inquired about the possibility of using an e21 320 5-speed. I already have one of those that was rebuilt by Jim Blanton. I just don't know if it will work with the M20.

Get the E30 318is 5-speed, the 5-speeds with a mechanical speedo are ridiculously expensive and you'll save a lot of money if you don't need it.

Or try to source a E30 320 5-speed, it's a 240 as well.

Might be a bit harder find in the US though.

although it obviously has the M10 bellhousing pattern, the rear gear carrier section of the transmission has a mechanical (cable) speedo drive and should interchange with the gear carrier from an E30 318 M42 trans. As far as I know, the 83 E21 240 gearbox has essentially the same ratios as the 245, so by combining the front case/bellhousing from an E30 M42 trans with the internals and rear carrier from an E21 240, you'd get an M20/M42 pattern belhousing, OD on 5th and a mechanical speedo drive............

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