M50B25 S1 swap question

[kanecvr]

Hi guys. Last week I bought a rusty old 1991 E34 525i really cheap and took the engine out to swap in my E30. The wiring harness matches the one in my E30 (same connector), and it came with a Getrag 260 gearbox identical to the one my M20 had.

I got hold of a set of E36 M50 engine mount arms, but I can't find any 535i rubber mounts for sale anyware in my country. No one sells them! Is there any other OEM rubber mounts I can use for the swap? Also, I heard that with the Getrag 260 I can use the E30 driveshaft. Is that true or do I need something else? Are there any other parts I need to take off the E34 for the swap? (I allready took the Power Steering hoses and reservoit since the E30 ones don't attach to the PS pump)

http://i.imgur.com/CdIKSpQ.jpg

http://i.imgur.com/2qoHWwq.jpg

http://i.imgur.com/H6GX2Gl.jpg

http://i.imgur.com/GZLXc2c.jpg

[mpowerful]

I am using the same mounts that came on that e34 on my swap. Cylinder shaped rubber and they work great. Should be able to use your driveshaft with g260. You sure its not g250? Just make sure. Also i highly doubt the harness is the same.

[kanecvr]

Thanks, will use the rubber mounts of the donor E34.

The engine's wiring harness has the same connector since the car is pre 1992. I even mated it to the car's wiring harness and it worked first try. The E36 / late model E34 connector has a triangular thing in the center. This does not.

The gearbox is a 260 - there are a few pictures of the engine and gearbox in the links above.

[kanecvr]

Some other things came up during the swap:

- the Getrag 260 gearbox that came with the M50 S1 had a large output flange, and my car has the M20 driveshaft with the small flange, so they would not match up. Also, the main bearings were shot, and the gearbox was leaking transmission fluid at the front and rear gaskets, so I decided to go with an M20 Getrag 260 witch was in good nick. Problem is, not all holes will bolt up! as it is, the gearbox is attached with four large bolts - the rest will not screw into the engine block...

- The gearbox will not align properly with the transmission mount. It's rotated a bit to the right (passenger side).

- There is very little clearance between the gearbox and the car... if I lift it up so that the intake manifold clears the brake booster, the GB touches the car's subframe... I will try to install a E60 5-series dual aluminum brake booster, and see if my e30 brake master will bolt up to it... If it does, I can use shorter engine mounts. Right now I'm using e34 engine mounts - one taller from a 525td on the driver's side and one shorter from a 525i on the passenger's side.

Could you guys look over the pictures and give some suggestions?

[kanecvr]

Gearbox is rotated. Gear linkage fit correctly, gear changes are nice and crisp, but the GB is slightly offset... I will try and use an M20 engine mount on the driver's side and a standard rubber gearbox mount on the passenger's side.




Wiring harness. The M50 S1 (non vanos) has the same connector as the E30 chassis. It will bolt right up and work with no cutting / soldering. Plug and play. Intake manifold does not clear the brake booster. Only a few millimeters of clearance, even tough I used a taller engine mount for the driver's side. Will try and swap the BB with an E60 booster I have lying around. I'll post some pictures if successful.




Some of the mounts I had around the garage. The small one is for the M20 engine, the tall ones are from an E34 525i. I used an even taller one (e34 525td) on the driver's side so the intake manifold will clear the brake booster. It didn't.




Engine position in the car. Sits just like it did in the donor E34. I used E36 6-cylinder engine mounting arms and E34 rubber supports. It sits about 2-3 cm from the firewall, so I didn't need to cut any of the sound proofing. There's also enough room at the front for a mechanical fan. I will be using an E34 radiator with built in expansion tank for a cleaner engine bay.

[mpowerful]

The g260 off of an m20 sits rotated 10° when mounted to an m50. You need to modify the trans brace or buy a modified swap trans brace. I did the later. There are a couple of people here on the forum that make the modified brace. Also you only need the four large bolts to hold the tranny on. Ive been like that for 6000+ miles no issue. The brake booster will def need to be changed if you have an e30 booster. Im using a modified 944 booster. I dont know if an e60 booster will work but there are a number of known working options. Some use stock master some not. Ix booster, e32 735 booster, e32/e34 v8 booster.

[kanecvr]

Yeah... I've been looking for e21 / e28 / e32 / e34 v8 brake boosters - no luck. Cars with large engines are very rare in my country because of the ludicrous taxes. E21s and E28s are EXTREMELY RARE and sought after. There are virtually none of them in scrap yards. Besides, my car has no ABS, so installing a BB and brake pump from a car that does have ABS will be complicated... As for parts sold here on the forum, the cost of shipping to Romania alone makes me want to search for other alternatives - like the Mercedes 190E brake booster. I have a buddy who parts mercedes cars, I'm sure he has one lying around. A porche 944 booster is out of the question. Those things are so rare here it's not even worth the effort to look for.

I did look for a new brake booster from the above mentioned cars (e21, 325ix, e28 535, E32, E34 v8, 944) - but they cost over 300$ and I don't have that kind of money to spend. For f*cks sake, I payed 400 euro for the E34 I got the engine out of!

I mentioned the E60 brake booster because I have one lying around. I also have an E65 brake booster with brake pump. They are both smaller then the stock e30 bb.

For mounting the tranny brace I'll be using one of the M20 engine mounts I have left, and an exhaust mount from a Dacia 1310. It looks kind of like a stock e30 tranny mount, but it's a little taller and thicker.

Weird thing is, the gearbox linkage is perfectly aligned. I used stock M20 gear upper gear linkage with a custom short-shifter I made a few years ago.

Will keep this thread updated. If the E60 or E65 brake boosters work, I will post pictures here.

[SmokeE30]

Sounds to me like your easiest booster solution would be to move the stock booster over to clear the intake and making a modified Clevis.

[kanecvr]

@SmokeE30 - I tought of that, but I'll try the Mercedes 190E brake booster first.

As it turns out, the E60 Brake Booster will bolt up to my car, and the push rod at the end is just a few mm longer so the brake pedal connects to it just fine. The problem is the E30 pump will not bolt onto it, and the E60 pump doesn't have the same outputs, since the E60 relies heavily on it's ABS.

I managed to lift the engine 1cm higher on the driver's side by installing an E65 740 engine mount (of all things) witch is a little taller than what I had before. It's all rubber, not hydraulic like on the 730d or 525tds, and it fit perfectly. This in turn created about 1cm of distance between the intake manifold and the brake booster. It's a temporary solution at best, but I can keep working on the swap this way (until I source another booster).

I wired everything together, and the engine turned over on the first try. I can't try to start it yet because I'm missing the MAF and the exhaust manifold isn't bolted on - I don't want to set the car on fire.

One issue I'm having: I can't figure out witch one of the two fuel lines under the intake manifold (near the brake booster) is the fuel intake line. It's not like on the M52TU or the M50TU, so I have no idea what i'm doing. See picture below:



Can any of you guys tell me witch one is the fuel feed line and witch one returns to the fuel tank? I've marked them as 1 and 2.

[kanecvr]

Ok, so I figured out the fuel lines - bottom is fuel intake, top is fuel return.

I managed to install the stock E30 tranny brace by using an E34 tranny mount and an e30 tranny mount, and took some measurements to have a friend modify one to my car's needs. Here is a picture.



Looks like shit, most likely won't hold out for long, but it helped me take some measurements.

[raudonis]

Looks to me like you are reinventing the wheel. I'm pretty sure this subject has been thoroughly covered on some Romanian BMW forum.

Study this manual (it is in German). http://e30-talk.com/attachments/e30-...e30-m50_52.pdf
Comprehensive list of engine and gearbox mounts with measurements:

http://e30-talk.com/attachments/e30-wikipedia/91907d1292532963-ubersicht-motorlager-und-getriebelager-motorlager.pdf

http://e30-talk.com/attachments/e30-wikipedia/107369d1309559480-ubersicht-motorlager-und-getriebelager-getriebelager_e30.pdf

Use VW Golf/Jetta or Renault Clio booster, google on this subject more. No one is using e21, e30 xi or Porche boosters in Europe.

[kanecvr]

Looks to me like you are reinventing the wheel. I'm pretty sure this subject has been thoroughly covered on some Romanian BMW forum.

Study this manual (it is in German). http://e30-talk.com/attachments/e30-...e30-m50_52.pdf
Comprehensive list of engine and gearbox mounts with measurements:

http://e30-talk.com/attachments/e30-wikipedia/91907d1292532963-ubersicht-motorlager-und-getriebelager-motorlager.pdf

http://e30-talk.com/attachments/e30-wikipedia/107369d1309559480-ubersicht-motorlager-und-getriebelager-getriebelager_e30.pdf

Use VW Golf/Jetta or Renault Clio booster, google on this subject more. No one is using e21, e30 xi or Porche boosters in Europe.

Thanks for the tip - will look into sourcing a VW or Renault Clio brake booster - they're pretty cheap.

As for the transmission brace, I was unable to find any relevant information (except for "buy a custom transmission brace to fit the E30 getrag 260" and "get a ZF tranny and E36 driveshaft"). I could have used a getrag 220 off an E36, but I don't like the gear ratios on it, would need another drive shaft (more $$$ spent), and both 220s I have in my garage are in poor condition. The 260 I installed is completely rebuilt by a friend of mine - was planning to bolt it onto the old M20.

As for the ZF gearboxes... had two on my M20B27 - they didn't survive for long.

It's much easier for me to fabricate a new brace for the gearbox I have on now. You may call it "reinventing the wheel" - I call it taking the best available route.

I will look over the documentation you linked - and thanks again for the brake booster tip.

[Edited] - looked over the documentation you linked. Great stuff, very helpful.