Manual swap help late eta into early eta g260

[namtua]

Hey guys I wanna start this off by saying any help with be greatly appreciated. I’ve referenced all the swap guides and transmission threads but couldn’t find a clear answer maybe somebody has another thread I haven’t seen. This is my 3rd time pulling the transmission and hopefully the last. I posted the whole story of everything I did but the last paragraph has almost all the information if it’s too much to read.




I have a 1985 325e (AUTO) I did as much research as I could thinking this would work and sourced parts local in my area because I am on a budget. I decided to go with what I think is a “late eta” trans. I chose it because it had the cps holes in the bellhousing (I didn’t know about the housing depth difference and reference pin on flywheel prior to this) the only reason I say I THINK is because it has a late model part number which is really confusing me. I’m assuming it’s a “late eta” because It has the deep bellhousing, shift linkage for late model, and big guibo. I’ll attach photos below.




First time, I knew it had a bigger guibo so I made an adapter plate. Keep in mind I didn’t know that the ETA’s rely on the cps in the boss holes of the bellhousing. The “late eta” g260 I purchased came with a small guibo drive shaft, “i” flywheel, and pedal set. I did the full swap and figured all of it out. It fired right up and drove just fine until I got down the street and it starts idle surging and backfiring out the exhaust like crazy. Found out the flywheel I had didn’t have the crank reference pin. This also confused me because I read through some other threads that it needed reference pin to even start the vehicle, and that I needed a 30mm guibo to make up the difference for the deeper bellhousing




Second time around I ordered an OEM flywheel through BMW. (It was for a 1985 325e, Single mass with reference pin). Took a month to come from Germany but threw it in a couple days ago and now it’s running way better but clutch wont engage or disengage from the pedal. Yesterday I decided to pull the transmission again to take some measurements and see what’s wrong. That’s when it brought me through this rabbit hole of e30 transmission/flywheel combinations. Now i’m confused and out of hope.




The 3rd and most recent time It seems like the clutch is always being disengaged. The car can be running and I can put the car into gear without the clutch and roll it back and forth like it’s in neutral even when in gear. So here’s my thought at first I thought the slave cylinder was too far pushed in for some reason so I removed it and put it into gear and confirmed that it was not the slave cylinder. Before pulling the transmission I went through the boss holes and took the cover off the bottom of the bellhousing and got in there with a boroscope and everything looked great. Since it drove before with the old flywheel I first thought the clutch could be free spinning, verified it wasn’t. Then it led me to believe since I put a thicker flywheel in, the spacing of everything is incorrect and when I bolt the trans up it pushes the fingers of the pressure plate in causing it to always be disengaged, making it feel like it’s always in neutral. I’m also confused because I have a late model trans part number but everything on the trans matches a “late eta” trans. I don’t know what else to do I feel so close but so far. I read if you run an “i” flywheel you need the thicker bearing to compensate for the space difference. I thought the thicker single mass “e” flywheel would make up the difference and everything would work correctly together but I was wrong. At the same time info doesn’t match because when I did have the “i” flywheel in I didn’t use the thicker bearing I did use the 2mm spacer that people say they run, and it drove fine. I measured both flywheels and the difference is about 7mm. My thoughts are having a machine shop shave down the “e” flywheel to the same height as the “i”, or put my own reference pin on the “i” flywheel. I’ve had no luck sourcing any early model transmission and i’m running out of ideas. Please see the pictures below maybe I read a measurement wrong or you’ll see something I didn’t see. Thanks so much for the read.

Please let me know if i’m measuring anything wrong or more measurements are needed. Thanks again.

See pictures below of bellhousing measurements.

[namtua]

See pictures of flywheel comparison and bearing measurement.

[namtua]

I also don’t think it matters but see pictures of clutch and pressure plate.

[82eye]

you could have an i trans and might be trying to fit e components. i recognize the number on the side of the trans.

there is a few threads here with the mix and match of parts for different swaps. i'm not that versed. start here:

The Official Transmission Thread - R3VLimited Forums

edit : my take on the swap is your single mass e fw is for a trans with bellhousing depth of 6 1/2 inches, and the trans should match if i read the numbers correct, as the i trans has the same depth. so the clutch / pressure plate / tob combo for an early car pre 04/86 should work.

[namtua]

you could have an i trans and might be trying to fit e components. i recognize the number on the side of the trans.

there is a few threads here with the mix and match of parts for different swaps. i'm not that versed. start here:

The Official Transmission Thread - R3VLimited Forums

edit : my take on the swap is your single mass e fw is for a trans with bellhousing depth of 6 1/2 inches, and the trans should match if i read the numbers correct, as the i trans has the same depth. so the clutch / pressure plate / tob combo for an early car pre 04/86 should work.

Hey thanks for the reply! I’ve referenced that thread many times and can’t find anything that’ll help me. I’m confused about the transmission because the p/n I have is for an “i” car but everything besides the p/n leads me to believe it’s a late eta trans with the deeper bellhousing. I have the boss holes on the bellhousing for the cps and the bellhousing depth is 6 7/8, I also have the bigger output flange. Do you know if I can run an “e” flywheel in a late eta trans with the deeper bellhousing?

[namtua]

I haven’t found any information so here’s my solution. I drilled and tapped the “i” flywheel, measured the pin to ensure i have the correct dimensions. Used a 10mm bolt and shaved down the edges to make it rectangle, used some red lock tight and went sideways with a punch to ensure it’s locked in there tightly since a socket would no longer fit. I’m going to be throwing the flywheel in monday morning fingers crossed hope it works. I do have high hopes because the differences of the flywheel thickness is only on the transmission side and it’s a 7mm difference, it would be the same as if I were to have it machined off the “e” flywheel. i’ll update this thread asap. If anybody has another solution please let me know.

[AWDBOB]

1346.90 is a late model trans, shallow bellhousing. Doesn't matter what car you have, matters what trans you have, in regards to stack height. Matters what car you have in regards to bellhousing crank pickup. I have NEVER seen a 1346.90 trans with a deep bellhousing.

Run all 325i components with that trans and you'll be golden.

You may need to convert to motronic 1.3 to do away with the bellhousing crank pickup

[82eye]

see above. you have a later trans. no doubt. i have an 89 325i and the trans has that number. it's sitting on my garage floor. the later trans had the cut outs for the dual mass flywheel sensors.

the pre 86 set up with the same depth bell housing should work. double check everything.

[namtua]

1346.90 is a late model trans, shallow bellhousing. Doesn't matter what car you have, matters what trans you have, in regards to stack height. Matters what car you have in regards to bellhousing crank pickup. I have NEVER seen a 1346.90 trans with a deep bellhousing.

Run all 325i components with that trans and you'll be golden.

You may need to convert to motronic 1.3 to do away with the bellhousing crank pickup

Ok thanks so much for the clarification maybe my measurements are wrong i’ll measure again. Hopefully the custom pin I put on the “i” flywheel works since it did drive before.

[namtua]

see above. you have a later trans. no doubt. i have an 89 325i and the trans has that number. it's sitting on my garage floor. the later trans had the cut outs for the dual mass flywheel sensors.

the pre 86 set up with the same depth bell housing should work. double check everything.

That makes a lot more sense. I didn’t know that the dual mass flywheels came with the flywheel sensors. Hopefully my modified flywheel works. Thanks for all your help!

[PEZ2]

Namtua looks like you are on the right path with the 325i flywheel, and your mod for the sensor pick up looks factory.

But with that said I’m still confused, there is lots of conflicting information here and between the “ official transmission “ post.
The 85 bmw provided single mass flywheel, pictured above is much wider than the 325i (7mm stated above), yet both supposedly come from a 6.5 inch shallow bell housing. Yet we know from this post it doesn’t work. The other thing is the difference when converted to faction inches is 3/8 of an inch which is the difference of the 6 1/2 and 6 7/8 or shallow to deep bell housings. I pulled a “fat” single mass flywheel from a deep 6 7/8 bell housing parts are on my bench now, which shouldn’t be if the deep bellhousing was for dual mass flywheels. ( official trans post) What gives? AWDBOB comment got me down this path…..there never was a shallow early e bellhousing, it would explain a few things. Additionally, the measurement is easy to screw up by the thickness of the bellhousing which is the difference of the deep and shallow. The change from deep to shallow was to support the 325i thin single mass flywheel, never found on an 325e.

[82eye]

Namtua looks like you are on the right path with the 325i flywheel, and your mod for the sensor pick up looks factory.

But with that said I’m still confused, there is lots of conflicting information here and between the “ official transmission “ post.
The 85 bmw provided single mass flywheel, pictured above is much wider than the 325i (7mm stated above), yet both supposedly come from a 6.5 inch shallow bell housing. Yet we know from this post it doesn’t work. The other thing is the difference when converted to faction inches is 3/8 of an inch which is the difference of the 6 1/2 and 6 7/8 or shallow to deep bell housings. I pulled a “fat” single mass flywheel from a deep 6 7/8 bell housing parts are on my bench now, which shouldn’t be if the deep bellhousing was for dual mass flywheels. ( official trans post) What gives? AWDBOB comment got me down this path…..there never was a shallow early e bellhousing, it would explain a few things. Additionally, the measurement is easy to screw up by the thickness of the bellhousing which is the difference of the deep and shallow. The change from deep to shallow was to support the 325i thin single mass flywheel, never found on an 325e.

he does not have a new i fw. he has an old 16 lb i fw and a new 28 lb pre 86 single mass e fw. he is trying to install the new e fw

the fw he has is the thicker e fw. it's the fw for all e cars pre 86. those are the unbadged cars. even though they were single mass fw cars they all used a thicker 28 lb fw. the dual mass fw for e cars did not show up until after 04/86. the 16lb fw did not show up until the i car.

the fw he has works with a 6 1/2 inch bell housing as long as it is paired with the stack from the pre 04/86 set up.

edit : the alternative is use the i flywheel with the i car stack from 88 and up, and convert the car to later motronic 1.3 with a new ecu and front mounted trigger wheel.

[namtua]

Namtua looks like you are on the right path with the 325i flywheel, and your mod for the sensor pick up looks factory.

But with that said I’m still confused, there is lots of conflicting information here and between the “ official transmission “ post.
The 85 bmw provided single mass flywheel, pictured above is much wider than the 325i (7mm stated above), yet both supposedly come from a 6.5 inch shallow bell housing. Yet we know from this post it doesn’t work. The other thing is the difference when converted to faction inches is 3/8 of an inch which is the difference of the 6 1/2 and 6 7/8 or shallow to deep bell housings. I pulled a “fat” single mass flywheel from a deep 6 7/8 bell housing parts are on my bench now, which shouldn’t be if the deep bellhousing was for dual mass flywheels. ( official trans post) What gives? AWDBOB comment got me down this path…..there never was a shallow early e bellhousing, it would explain a few things. Additionally, the measurement is easy to screw up by the thickness of the bellhousing which is the difference of the deep and shallow. The change from deep to shallow was to support the 325i thin single mass flywheel, never found on an 325e.

SOLVED! Mod for the flywheel pickup on the “i” flywheel worked. I’m still confused about the contradicting information not sure what to believe. But drove the car home today from work and it runs great. Lesson learned, next time get the right parts for the right car would’ve saved me so much time in the long run but hey I was able to do it for real cheap. Thanks everybody for the help.

[namtua]

he does not have a new i fw. he has an old 16 lb i fw and a new 28 lb pre 86 single mass e fw. he is trying to install the new e fw

the fw he has is the thicker e fw. it's the fw for all e cars pre 86. those are the unbadged cars. even though they were single mass fw cars they all used a thicker 28 lb fw. the dual mass fw for e cars did not show up until after 04/86. the 16lb fw did not show up until the i car.

the fw he has works with a 6 1/2 inch bell housing as long as it is paired with the stack from the pre 04/86 set up.

edit : the alternative is use the i flywheel with the i car stack from 88 and up, and convert the car to later motronic 1.3 with a new ecu and front mounted trigger wheel.

Flywheel mod ended up working! Thanks so much for all your help.