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.
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.
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