I just picked up a '77 242 with the B21F and BW35 3-speed. I want to swap the transmission with an M47 out of a running/driving, beater '88 240 with a b230f. Is the bell housing a direct bolt on without adaptors?

Are there any other major issues? Crank position sensor, drive shaft, cross member location?

 

automatics and manuals have different drive shafts. afaik, they all have compatible bolt on bell housings. neither your B212F nor an 88 B230 has a crank position sensor. pretty sure the 88 3-pedal assembly will bolt up to the 77. I dunno if 88's have a hydraulic or a cable clutch (never owned a 240 manual).

 

oh, the final drive ratios are probably different.

I dunno if a 77 has a electronic or cable actuated speedometer but I'm pretty sure the instrument panels are totally different so not swappable. I believe the cable/mechanical speedos come off the gearbox output shaft, and the 88's M47 probably doesn't have that fitting.

 

ok thanks.
yeah, the m47 is electric speedo and the 77 242 bw35 is cable driven. i can deal with no speedo and use gps speedo if i need to, but definitely want the manual m47 on my 242. are there issues other than that you know of? i have the all the parts; drive shaft, flywheel, salve cylinder, etc with the m47.

 

A bit crazy perhaps, but if you have someone who's a bit of an electronics nerd, you could probably do something with a small electric motor connected to the speedo cable, and the electric speedo pickup and tone ring from a later car. a bit of electronics (I'd probably use a 'PIC' processor) to track the pulse rate from the electric speedo pickup, and spin the motor at the right speed. a few test runs to calibrate it, done.