Swap M3 S50 into 1992 BMW 525i

[bissellh]

Will you guys help me through the technical issues of swapping a 1995 M3 S50 engine into my 1992 BMW 525i? The three areas that I am looking for advice in are (1) electronics, harness, ECU, etc, (2) fitment, oil pan, etc and (3) flywheel, clutch, transmission.

The M3 engine I bought is from eBay with eBay item # 180322003632. Here is the link:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=180322003632&sspagename=STRK%3AMEWNX%3AIT&viewitem=
The seller had swapped this engine into a 325i with manual transmission. It is coming to me without a flywheel, transmission and clutch. But, it does come with all accessories, wiring harness and ECU with Turner chip with EWS delete.

(1) My car has a non vanos M50 engine. The S50 engine is a vanos engine. Will I be able to plug in the S50 harness into my E34 without modification?

(2) Will the original M3 oil pan fit my E34 or will I have to swap the E34 M50 oil pan and oil pickup onto the S50 engine? I guess since the seller swapped this engine from a M3 E36 to a 325 E36 that he probably did not have to swap the oil pan.

(3) Can I use my M50 flywheel, clutch and transmission with the S50 engine? I looked up the transmission on my 1992 BMW 525i M50 US spec with manual transmission and 03/92 production date on www.realoem.com. It lists a G and a Z transmission. I have not been under my car to see which one I have yet. It seems to me that the horse power difference from the M50 to S50 is not that great. So, I could probably get away with reusing my setup. Could I turn my flywheel to balance it and take a couple of pounds off it and use it with an M3 clutch? Can an M3 clutch be used with my transmission or will I be required to use an M3 transmission? If I am required to use an M3 transmission, will it be the same length as mine or will I need a custom drive shaft? By the way, I have a 3.91 LSD differential in my car now.

Thanks guys!

[bad_manners_god]

These links should help:

http://forums.bimmerforums.com/forum/showthread.php?t=933701

http://forums.bimmerforums.com/forum/showthread.php?t=729157

[repenttokyo]

you have to swap in an m50 oil pan because of the crossmember on our cars.

[bissellh]

you have to swap in an m50 oil pan because of the crossmember on our cars.

I imagine I will have to swap the oil pickup as well since the pan is different. Is that correct?

[bissellh]

These links should help:

http://forums.bimmerforums.com/forum/showthread.php?t=933701

http://forums.bimmerforums.com/forum/showthread.php?t=729157

Clicking on those links did not work for me. Is there another way I can find those pages?

[bissellh]

I imagine I will have to swap the oil pickup as well since the pan is different. Is that correct?

I purchased an E34 oil pan and pickup tube and pickup tube gasket from my friend Mike. He has parts from a wrecked an E34 donor car. Once I had the E36 oil pan off, it was obvious what needed to be done. I had to remove the crank scraper that came with my donor S50 engine - bonus! I removed the M3 pick up tube and replaced it with the E34 oil pickup tube with a new oil pickup tube gasket. One of the oil pickup tube bolts was a little tough to access, taking it out and putting it back in. I guess it would have been easier if I had the oil pump out too. I replaced the crank scraper. Finally, I installed the E34 oil pan with a new oil pan gasket and some ultra black gasket maker.

I have installed oil pans from under the car. It was much easier with the engine up on an engine stand.

[Sam-Son]

use the m50 mani as well

[bissellh]

Will you guys help me through the technical issues of swapping a 1995 M3 S50 engine into my 1992 BMW 525i? The three areas that I am looking for advice in are (1) electronics, harness, ECU, etc, (2) fitment, oil pan, etc and (3) flywheel, clutch, transmission.

The M3 engine I bought is from eBay with eBay item # 180322003632. Here is the link:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=180322003632&sspagename=STRK%3AMEWNX%3AIT&viewitem=
The seller had swapped this engine into a 325i with manual transmission. It is coming to me without a flywheel, transmission and clutch. But, it does come with all accessories, wiring harness and ECU with Turner chip with EWS delete.

(1) My car has a non vanos M50 engine. The S50 engine is a vanos engine. Will I be able to plug in the S50 harness into my E34 without modification?

(2) Will the original M3 oil pan fit my E34 or will I have to swap the E34 M50 oil pan and oil pickup onto the S50 engine? I guess since the seller swapped this engine from a M3 E36 to a 325 E36 that he probably did not have to swap the oil pan.

(3) Can I use my M50 flywheel, clutch and transmission with the S50 engine? I looked up the transmission on my 1992 BMW 525i M50 US spec with manual transmission and 03/92 production date on www.realoem.com. It lists a G and a Z transmission. I have not been under my car to see which one I have yet. It seems to me that the horse power difference from the M50 to S50 is not that great. So, I could probably get away with reusing my setup. Could I turn my flywheel to balance it and take a couple of pounds off it and use it with an M3 clutch? Can an M3 clutch be used with my transmission or will I be required to use an M3 transmission? If I am required to use an M3 transmission, will it be the same length as mine or will I need a custom drive shaft? By the way, I have a 3.91 LSD differential in my car now.

Thanks guys!

My oil pan and oil pickup tube swap is complete. I decided to purchase a 1995 525i E34 M50 vanos engine wiring harness (EWH) without ASC to better match the 1992 BMW 525i E34 M50 non vanos that I am swapping the BMW 1995 M3 vanos engine into. My old EWH is non vanos. The EWH that came with the S50 engine does not have a plug for the oil level sender that is on the E34 oil pan. Instead of adding extra wires for that, I decided to keep the engine bay clean in case of resale.

I decided a light weight 16lb flywheel and stage 3 clutch in conjunction with the original transmission on my car. This way I do not have to worry about matching up an M3 transmission with the drive shaft in my car. The M3 clutch should be able to hold up to the M3 engine with no problem. Plus, it will save me some money, as I have been spending a lot recently.

Now, I am wondering about which alternator to use. My 525i has a 140 amp alternator. The S50 donor engine has a 80 amp alternator. I have been hearing that it does not matter which one I use since they are both 12V. Does anyone have any isdeas on this?

[bissellh]

use the m50 mani as well

Sorry I do not understand the lingo. Is a mani the manual transmission or the intake manifold? I still do not know if the transmission in my 525i is the G or Z. If it is the Z, it is the same as the one used M3. If it is the G, it is less sturdy. Isn't the intake manifold the same on the M50 and S50 engines?

[Sam-Son]

the intake manifold off the M50. take it and put it on the S50 the stocker strangles the HP out of the engine. and M50 intake mani is a common upgrade for E36 guys.
if your car is a 92 manual then its a ZF manual gearbox.

[bad_manners_god]

Mani refers to intake manifold, the M50 manifold is MUCH less restrictive than the S50 Manifold

[bissellh]

the intake manifold off the M50. take it and put it on the S50 the stocker strangles the HP out of the engine. and M50 intake mani is a common upgrade for E36 guys.
if your car is a 92 manual then its a ZF manual gearbox.

The previous owner may have already swapped the mani to an M50. I will have to check once I have the two engines side by side. Any ideas on which alternator to use, the M3 80 amp or the 525i 140 amp?

[bissellh]

Mani refers to intake manifold, the M50 manifold is MUCH less restrictive than the S50 Manifold

The previous owner may have already swapped the mani to an M50. I will have to check once I have the two engines side by side. Any ideas on which alternator to use, the M3 80 amp or the 525i 140 amp?

[Spice Boy]

I would use the 140 as it will help deliver the needed power to the whole car with less strain....

Plus its classed as an upgrade at the factory (according to BMW)

I am doing exactly the same as you are, although I am at an earlier stage than yourself....

I will be trying to use the gearbox from an M3 but Im having problems finding out if you can use the standard prop or if the M3 prop is lightened/strengthened/different mounts etc...