The timing pin on my 85 325e flywheel flew off. Instead of investing the labour to fix the pin it sped up my engine swap plans. Thanks to Rudi and Marcus they found me a 325i motor with all the accessories required to do the swap. I took their recommendation and they put on a new timing belt, waterpump and rod bearings plus adjusted the valves.
The electrical was the only real unknown as the early 325e uses a "square" C101 connector and the M20B25 engine is a round C101 connector. After pouring through the entire electrical manual of the two cars, I stumbled upon a dude who makes the harness for $150. Close to buying that I found a rogue service manual page from BMW which shows the two connections side by side. Almost like BMW was showing us how to swap it!!!
I made the harness (again thank's Rudi and Marcus for letting me cut a fuse box from another car) a few weeks in advance and crossed my fingers.
The swap actually wasn't that tough and within about 3 hours we had the old motor out. That evening around 10 am we cranked the car (about 8 hours of actual working). Nothing. After 20 minutes my buddy realized that I had put the starter trigger wire on the wrong terminal to my old starter. The car fired right up!
Some notes on the swap:
1) My early eta starter has a spade terminal for trigger. The newer harness has a round terminal, cut the round off and made a spade.
2) Larger DME computer in my older glove box will take a bit of moving around to get the glovebox to close nicely.
3) Reused my old distributor cap and rotor and all the wires (all new) except #6 from the old engine which contained the pulse generator.
4) Reused old transmission. Received installed clutch with new motor. Now my throw out bearing is rattling around. Odd but the old engine combo was very hard to shift. Perhaps input shaft wasn't lubed. New combo is smooth as silk.
4) Installed the old crank and pulse trigger in the old transmission to cover up the holes.
5) Small modification to fuel feed line (its much shorter and comes under the intake, versus up and over). Return line the same.
6) Need 4 wire heated O2 for new computer versus old 3 wire non-heated. Remember you not only need the new O2 sensor, you will also need the harness that connects it. I didn't realize this so we made a 3 ft harness.
7) Oil cooler. Bent up a few brackets and welded them to the bottom of the car. The mounting of this piece and fabrication was probably the most complex part of this swap, and that itself was cake.
8) The new AFM air intake is larger than the eta so the "horn" that connects the airbox to the plastic behind the headlights I will need to find.
9) New harness has a cluster of grounds that bolt to where the battery would be in a convertible, as opposed to the old harness which has a small ground off various parts of the engine and one from the valve cover to the same tray. Looks like a more stable ground supply. Reused the large ground off my old engine to the body side (from near the kick out of the oil pan on driver's side).
10) Upper coolant crossover hose is very close to clutch fan. Don't remember this on old engine but maybe I never paid attention. Its not hitting, but about 1/2" from the fan.
11) Feels good to not have like 10 coolant temp sensors that cost $50 each and a wacky idle system that is overly complex.
Car sounds awesome, even with the more restrictive eta exhaust. With my 2.73 eta gear I can do 110 km/hr in 2nd gear. LOL.... time for a diff swap.
I'll probably add to this post as I remember any tidbits, but aside from making that connector to the two C101 harnesses, the swap literally was plug and play.