The comprehensive DOHC engine swap thread.

[MatRacer]

I bought an e30 with an s50 The speedo and the tach doesn't work.

Tach: An aftermarker tach was in the car and working when I bought the car, but i really don't like it. It was plugged on the black wire of the S50 ECU. Moreover, the black wire of the ECU is also connected to the black wire of the cluster. I think its on the blue plug, but i'm not sure.

To make the e30 325es tach work, what I need to do. I tough that eta e30 had 5k rpm, but mine has 7k...? What is the wire color/location of the tach on the cluster

Speedo: the speedo isn't working either. The car as a triple clutch diff from diff online with a z3 diff cover... What is the color/location of the wires for the speedo on the the cluster?


Any help would greatly be appreciated!

Thanks!

[gregslow318i]

Thanks, now I need to find an e36 driveshaft as I did not start with a donor car, just the motor and transmission.

I'll scour the local junkyards first and then on to ebay!

I think I have one pm me if you need it

[bykerboy]

golden rule for the e30m50 trans question. use the drive shaft that came in the car the the trans came out of. so in your case the 250 came in the e36 (e36 trans are the same between the 325 and 318is iirc same with the driveshafts just looked on realoem) so use the e36 drive shaft w/a e30 gybo and a e30 center support. no need to swap flanges or have a custome drive shaft built.

Thanks, now I need to find an e36 driveshaft as I did not start with a donor car, just the motor and transmission.

I'll scour the local junkyards first and then on to ebay!

[gregslow318i]

golden rule for the e30m50 trans question. use the drive shaft that came in the car the the trans came out of. so in your case the 250 came in the e36 (e36 trans are the same between the 325 and 318is iirc same with the driveshafts just looked on realoem) so use the e36 drive shaft w/a e30 gybo and a e30 center support. no need to swap flanges or have a custome drive shaft built.

I have read this thread multiple times and done some additional research and would like the experts here to validate what I have found about which driveshaft to us.

I am doing an M50 swap using the Getrag 250 transmission into my '89 325is. My understanding is the ouput flange bolt circle diameter (BCD) on the Getrag 250 is 78mm. The output flange on the Getrag 260 (from my 325is) has a 96mm BCD. Based on this I assume I can not use my e30 driveshaft. From what I have read the e30 318is transmission is a Getrag 240 with a 78mm BCD. I believe this is why I can use a 318is driveshaft. The only other thing I can not ascertain for certain is the bolt diameter on the 318is driveshaft. The Getrag 250 has 12 mm bolt holes and the Getrag 260 has 10mm bolt holes.

Does anyone know the bolt hole diameter on the Getrag 240 output flange?

Lastly, I have read on here that someone recommended a 318is driveshaft out of an automatic car. What is this?

Thanks....

[bykerboy]

I have read this thread multiple times and done some additional research and would like the experts here to validate what I have found about which driveshaft to us.

I am doing an M50 swap using the Getrag 250 transmission into my '89 325is. My understanding is the ouput flange bolt circle diameter (BCD) on the Getrag 250 is 78mm. The output flange on the Getrag 260 (from my 325is) has a 96mm BCD. Based on this I assume I can not use my e30 driveshaft. From what I have read the e30 318is transmission is a Getrag 240 with a 78mm BCD. I believe this is why I can use a 318is driveshaft. The only other thing I can not ascertain for certain is the bolt diameter on the 318is driveshaft. The Getrag 250 has 12 mm bolt holes and the Getrag 260 has 10mm bolt holes.

Does anyone know the bolt hole diameter on the Getrag 240 output flange?

Lastly, I have read on here that someone recommended a 318is driveshaft out of an automatic car. What is this?

Thanks....