I've decided to take the plunge.

[MNE30]

After repeated issues with my M20B25 paperweight in my 1991 325i, I've decided it would be best to just store it until I can get an M50/M52 in it. It was my original intentions to do an S52/S50 swap right off the bat but I couldn't find a shell so I got a semi-running 325i. I don't want to keep dumping money into an engine that I will be ripping out sooner or later.

After some intense thinking I've decided the price of the S5x isn't worth it for me, I'm not looking for a race car build just something with a little more bite than my current M20.

So, I've clearly got some concerns and I would feel a lot better about this if someone could directly address them. I've done countless hours of research and studied my ass off about this swap, and trust me I not only used, but violated the search button on every forum I could find.

So to start things off, here is what I think I will need for the swap, this is off the top of my head:

M5x with accessories
Getrag 250 or ZF 310 or 320 (any preference?)
Not sure which driveshaft to use, depends on tranny
OBD I wiring harness (I'm choosing to go the OBD I route)
E34 Oil pan for the M5x (unless I pull the engine from an E34 525i)
E34 Throttle cables
E36 engine mounting arms
E28 M5 engine mounts
E36 Rad + a fan (upgrade I guess, my current Rad is pretty beat up)
Custom fab an exhaust

My next concern is the difficulty level, I understand that it's all fairly bolt on for the most part, but my main concerns are the wiring, I'm not very good at electrical stuff. I can solder and all that jazz though. How hard would you say the wiring is to do for a beginner, with limited knowledge of wiring?

From engine laying in a heap in my garage, to running and driving around with the ladies in my E30, how long does the swap take? My best guess, with my basic mechanical skills and the assistance of my equally skilled friend it would take a weekend to get the engine in and running. Anyone who has done it before care to comment?

And lastly, anyone local to MN that would be willing to lend a helping hand if needed? I can pay you in beer, since that seems to be a valid currency with you guys :mrgreen:

[LivingLegend06]

After repeated issues with my M20B25 paperweight in my 1991 325i, I've decided it would be best to just store it until I can get an M50/M52 in it. It was my original intentions to do an S52/S50 swap right off the bat but I couldn't find a shell so I got a semi-running 325i. I don't want to keep dumping money into an engine that I will be ripping out sooner or later.

After some intense thinking I've decided the price of the S5x isn't worth it for me, I'm not looking for a race car build just something with a little more bite than my current M20.

So, I've clearly got some concerns and I would feel a lot better about this if someone could directly address them. I've done countless hours of research and studied my ass off about this swap, and trust me I not only used, but violated the search button on every forum I could find.

So to start things off, here is what I think I will need for the swap, this is off the top of my head:

M5x with accessories
Getrag 250 or ZF 310 or 320 (any preference?)
Not sure which driveshaft to use, depends on tranny
OBD I wiring harness (I'm choosing to go the OBD I route)
E34 Oil pan for the M5x (unless I pull the engine from an E34 525i)
E34 Throttle cables
E36 engine mounting arms
E28 M5 engine mounts
E36 Rad + a fan (upgrade I guess, my current Rad is pretty beat up)
Custom fab an exhaust

My next concern is the difficulty level, I understand that it's all fairly bolt on for the most part, but my main concerns are the wiring, I'm not very good at electrical stuff. I can solder and all that jazz though. How hard would you say the wiring is to do for a beginner, with limited knowledge of wiring?

From engine laying in a heap in my garage, to running and driving around with the ladies in my E30, how long does the swap take? My best guess, with my basic mechanical skills and the assistance of my equally skilled friend it would take a weekend to get the engine in and running. Anyone who has done it before care to comment?

And lastly, anyone local to MN that would be willing to lend a helping hand if needed? I can pay you in beer, since that seems to be a valid currency with you guys :mrgreen:

If your worried about wiring it might be easiest to get a wiring adapter from a forum member. As long as your are dedicated to getting your swap running then you should be able to do it. Nothing is too difficult and all the information you could need is already out there you will just need to find it.

M5x with accessories
Getrag 250 or ZF 310 or 320 (any preference?) G260 and 240 are also common to use. you may already have a G260 in your M20 car. Of the listed transmissions the ZF320 is the best but they will all work fine.
Not sure which driveshaft to use, depends on tranny
OBD I wiring harness (I'm choosing to go the OBD I route)
E34 Oil pan for the M5x (unless I pull the engine from an E34 525i) E34 oil pump too.
E34 Throttle cables
E36 engine mounting arms
E28 M5 engine mounts
E36 Rad + a fan (upgrade I guess, my current Rad is pretty beat up) There are ton of options here, I'm using an M42 radiator, a lot of people use the standard M20 radiator as well.
Custom fab an exhaust

[Holland]

Wiring on these swaps are as simple as re-pin on a connector. If you are going to go through the trouble of a swap, I think the M52 would be more worthwhile than an M50.

[evandael]

obd2 on an m52b28 with s52 cams, at the least.

most of the swap costs are the 'extras', not the cost of the motor.

[Cyrix2k]

If your worried about wiring it might be easiest to get a wiring adapter from a forum member. As long as your are dedicated to getting your swap running then you should be able to do it. Nothing is too difficult and all the information you could need is already out there you will just need to find it.

M5x with accessories
Getrag 250 or ZF 310 or 320 (any preference?) G260 and 240 are also common to use. you may already have a G260 in your M20 car. Of the listed transmissions the ZF320 is the best but they will all work fine.
Not sure which driveshaft to use, depends on tranny
OBD I wiring harness (I'm choosing to go the OBD I route)
E34 Oil pan for the M5x (unless I pull the engine from an E34 525i) E34 oil pump too.
E34 Throttle cables
E36 engine mounting arms
E28 M5 engine mounts
E36 Rad + a fan (upgrade I guess, my current Rad is pretty beat up) There are ton of options here, I'm using an M42 radiator, a lot of people use the standard M20 radiator as well.
Custom fab an exhaust

no e34 oil pump is needed, just the oil pump pickup. Get the (pickup) gasket too.

I'll reiterate this from my post on bf.c:

I run the Getrag 250s... they're fine behind an M50. The ZF will use a different driveshaft, but the 250 uses an OBD-I e36 driveshaft or an early e30 driveshaft. Use the e36 shift linkage & slave cylinder. I can do wiring, but I don't think it's hard at all if you get an adapter. Mine's running on stand alone so it was a bit different for me, and the second one arrived already wired. A standard clutch fan will not clear the e36 radiator. Use e36 hoses for the radiator. You're also forgetting the brakes - you need to either slot the firewall or swap boosters. I like the Porsche 944 booster since it uses the factory master cylinder and fits correctly. See here http://www.rjnunnally.com/how-to-fit...ter-to-an-e30/ It's unlikely you'll have it in and running in a weekend, but possible.

IMO, the G240 should be avoided. I have one behind an M50, but I wouldn't want to beat on it. The G260 works but requires modification to the trans cross-member & shift linkage.

[MNE30]

So if I'm going to the trouble an M52 would be a better choice?

And a ZF 320 seems like a good transmission to use since it bolts right up to the stock mounts, I want to do as little fabrication as possible.

M52 paired with a ZF320 seems good. I want to move my current brake booster or just use a B5 A4 brake booster since my friend has a parts A4 laying around.

[deutschman]

Moving your brake booster is going to take fabrication.
I would go with the 944 booster or by a booster from Zionsville

http://www.zionsvilleautosport.com/store/screen/prod/store_code/6134/product_code/POMBB.htm

Also you can get a great harness from these guys.

http://www.markertmotorworks.com/MMWProducts.html

Check out the Wiki here

http://www.e30dohc.com/wiki/index.php?title=DOHC_Swap_Basics#What_Are_the_Required_Parts

[TimKninja]

A well maintained M20 won't feel much slower then an m50.

If you change to a ZF Trans, finding a driveshaft sucks. Then you have to also change your diff.

If your JUST doing an m50/2 swap use your pre-existing tranny .

Wiring is like the easiest part of this swap. Ive done two of these swaps and
Never had to touch my wiring after I Initially spliced the wires together. If you follow the pin outs , write down your own chart , it's easy as pie .

You most likely Will NOT get it done in a weekend. Unless you wanna do it half ass and have reliability problems. I'd say maybe 2-3 weeks done right. Take your time. The fabrication of the exhaust took me 5 hours alone.

[MNE30]

A well maintained M20 won't feel much slower then an m50.

If you change to a ZF Trans, finding a driveshaft sucks. Then you have to also change your diff.

If your JUST doing an m50/2 swap use your pre-existing tranny .

Wiring is like the easiest part of this swap. Ive done two of these swaps and
Never had to touch my wiring after I Initially spliced the wires together. If you follow the pin outs , write down your own chart , it's easy as pie .

You most likely Will NOT get it done in a weekend. Unless you wanna do it half ass and have reliability problems. I'd say maybe 2-3 weeks done right. Take your time. The fabrication of the exhaust took me 5 hours alone.

I'm thinking M52 and eventually dropping in S52 cams so I'd like to get something a bit stronger. And My M20 is not very well maintained right now, it has quite a few issues that I don't want to deal with right now. It seems to run alright, but it is running fairly hot (3/4 on the temp gauge) and every once in awhile has a rough idle, I just don't want to deal with figuring it out if I'm going to swap eventually.

[cormier]

I'm thinking M52 and eventually dropping in S52 cams so I'd like to get something a bit stronger.

I think he meant more that the $$ difference between m5x and s5x motors is small compared to the power difference and that an m5x will not necessarily be a big improvement over your m20. Not to mention you'll spend like three times that difference in add-ons for whichever motor you choose.