m21 swap underway

[golde30]

damn, i thought that was gonna do into an e30. that would have been sick.

[rs4pro3]

well if somebody wants to donate me an e30 rolling chassis I'll do it
But I've already have one e30 that takes way to much of my money with 2 of them i'd be broke

[kway]

Will you cut out the core support to make the m21 easier to install in the recipient?

J/K I like your style, man! I'd have done the same. Looks like a fun project.

[rs4pro3]

no, getting the new engine in will be easier with the smaller manual tranny attached to it. I need to get some pics of the rust on the turbo diesel, both frame rails are rusted out, all 4 jack spots are rusted, I can see the carpet from the underside in multiple places, sway bar mounts are about to rip out of the body etc... needless to say i didn't feel bad at all taking the saw to the TD

[scabzzzz]

Dang Ely. You need help? I dont see why Don and me couldnt make a trip down one weekend.

[rs4pro3]

thanks for the offer man. But I think i've got it covered. Plus i'll probably be swapping the engine out next week on a weekday, and try and have it all buttoned up by the weekend

[rs4pro3]

Got the 5-speed mounted up to the engine tonight.

Flywheel on


I mounted up a bell housing to make sure that the e30 starter engages the flywheel. The m21 flywheel has a different pitch to the teeth then the e30 flywheel so you have to use an e30 starter(hopefully it's powerful enough to spin over the diesel)

Clutch disk/pressure plate bolted in place


tranny is on

[AndrewBird]

What motor is the tranny off of? I'm confused as to why you had to use an M20 flywheel when it looks like the transmission you are using was intended to be used with that motor (meaning there is a flywheel that would fit).

[rs4pro3]

Well the turbo diesel was never offered in the U.S. with a manual tranny. The European version did have manuals. But the flywheels are diesel specific as they have those 6 trigger pins on the back of the flywheel and they are a dual mass flywheel like the late eta's. Where as I'm making m20 parts work on the m21 engine. I'm using an 85 325e flywheel and clutch assembly, and an 89 325i 5-speed tranny. The pitch of the flywheel teeth is different between the m20 and m21 engines so you can't use the m21 starter on the m20 flywheel. So I had to install a m20 starter. I wanted to check and make sure the m20 flywheel has enough throw to engage the flywheel, as I don't want to have it all together and in a car and come to find out something else is going to have to be done. Plus there is a LOT of misinformation out there about doing a 5-speed swap in the TD. I've seen threads where a guy swears that an m20 5-speed won't bolt up to the TD block, but come to find out he was using a 265 tranny and didn't have an m20 bell housing on it. Since these cars are so rare not many people have taken on a 5-speed swap and documented it, I know one other person who did but they found all the TD specific parts in europe and had them shipped over.

[Erik j]

Are you sure the m20 starter will have the power to turn that motor? Ive got a m21 in my Motorhome and it has a bad starter in it, but a new one is 500$. Are you going to do a dry run before you put it into the car just to make sure that motor can turn it, I would hate to see you get it all together just to find you have to take it all apart again.

[rs4pro3]

Ya I'll test it first, from what i've found on the TD yahoo group is that the m20 starter will work. If it won't I'll take the m20 gear and stick it on an TD starter

[Erik j]

So what mods would I have to do to a normal m21 with a manual to get the m20 starter to fit right I wonder. Cause like I said my RV has a m21 in it, but the starter is bad. I think it might be very very different due to the fact that my m21 is hooked to a Renault tansmission.

[rs4pro3]

Without changing the flywheel I'd think you could just take the bendix gear from the m21 starter and stick it on the m20 starter. The late model 325i starters are a gear reduction starter so it should be strong enough, or I read also about using the m50 starter. This is the first time I've every touched a TD so it's all new territory to me so I'm learning as I go.

[dude8383]

Are you going to clean that thing up a bit? It looks pretty nasty!!

Kick ass project though...

[Erik j]

Without changing the flywheel I'd think you could just take the bendix gear from the m21 starter and stick it on the m20 starter. The late model 325i starters are a gear reduction starter so it should be strong enough, or I read also about using the m50 starter. This is the first time I've every touched a TD so it's all new territory to me so I'm learning as I go.

First time for me on the m21. Your lucky enough to have space to work on the engine, Mine is stuffed under a full sized bed in the back of my rv