Swapping M42 engines, need advice

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victell

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Swapping M42 engines, need advice
« on: September 04, 2019, 08:50:11 PM »
My e30 318is has a blown head gasket or worse. I will be swapping in a known-good m42 from a donor car in order to get back on the road as soon as possible. My friend is letting me borrow his 2-car garage for the swap so thats another reason to finish quickly. In the interest of minimizing potential issues and time working I need advice.

Which is easier, pulling the engine out by itself or pulling the engine and trans assembled as one unit? The pros and cons as I see it:

Pull engine alone
+ pro: only have to remove downpipe portion of exhaust
+ pro: easier to maneuver than engine+trans together
- con: may have difficulty mating engine and trans back together in the car

or

Pull engine and trans as one unit:
+ pro: don’t have to worry about getting engine and trans mated back together
- con: have to remove and reinstall exhaust, heat shields, driveshaft, shifter, clutch slave
- con: more difficult to maneuver

Ive never pulled an engine or trans on an e30. But on other cars I've had hours of frustration trying to get an engine and trans to mate back up in the car. Sliding the trans input shaft through clutch disc and into the pilot bearing can be a bitch sometimes. Ive never done it on an m42/g240 but am worried it could be the same or worse. What should I do?

victell

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Re: Swapping M42 engines, need advice
« Reply #1 on: September 11, 2019, 08:54:52 PM »
I ended up pulling just the engines and leaving the transmissions in vehicle. I wanted to keep my trans, so would have had to pull them apart anyways. Also I was concerned if I could maneuver the engine+trans over the radiator core support and still clear the garage door above.

I used a load leveler and got three m12-1.75 100mm threaded rods to use as extended guide pins. These two things helped and we got them mated back up about 90 minutes first engine, 45 minutes 2nd engine.