1988 520i imported from Germany

[Mrneau]

I recently purchased this car it has a m20b20 motor in it but the previous owner installed a m20b27 head on it now it won't run. My question is plenty of people do the b27 block with a b20 head, will it work doing it the opposite way? Sorry I am used to dealing with ford and chevy v8's

[shogun]

E28 model? Or already E34? E28 was produced till end of 1987. Pls add that to your profile

My Cars: 1988 BMW 520i

I will move it to the E34 forum, in case it is an E28, let me know, and I will move the thread to the E28 forum.
You can check the model , production month and yesr and part numbers here when you type in the VIN http://bmwfans.info/parts-catalog

[ross1]

I don't think a 2.7 ETA head(odd choice)will prevent it from running. Lots of other things that could prevent it from running, including improper valve timing when the head was done.
Doesn't run? Ditch that wheezing 2 liter turd and get at least a b25, they are cheap, cheap, cheap.

[ross1]

I'll bet the fellows in the E30 forum will have more knowledge about M20 engines

[bigsixe34]

I thought the common build was to stick a b25 head on an eta block? I.e. reverse of what you have.
That would give you the 2.7 bottom end with a valvetrain that can handle more than 4.5k or whatever the pathetic redline is on the 325e
edit: so you have an e30 320i?

[Mrneau]

It is an e34 model

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I have been reading a lot of different ideas and they all say this forum is the place to be. I was thinking m20b25 and either turbo it or supercharger. This will just be a road coarse car so need the lowend torque more than highend horsepower

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It was sold to me as a 1988 520i e34 but once it arrives I can run the vin

[bigsixe34]

Most people including myself will suggest a 24 valve swap. M50b25 from an e34 or e36 being your simplest option, and S52b32 from the e36 being your most impressive performance wise. Speaking of boost, a properly setup turbo s52 e30 will eat some serious cars for dinner. Of course there are higher powered options I.e S54 from the e46 and Z3 M but then you are looking at big coin, and by the way that torque you speak of, it’s non existent in an e46 M. IMO they’re disappointing to say the least.

okay you need to figure out what you own before you press on here...

[Mrneau]

Well I do know it has a m20b20 block right now with a m20b27 head. I just confirmed with original owner it is an e34 520i

[bigsixe34]

Ok then you have a couple logical avenues you could pursue.
Ross is probably right in his suspicion that it should run as is and isn’t because of a setup error. So just getting it to work would be the easiest. I can assure you however that “torque”, “speed”, and “power” will not be part of your vocabulary when describing its stock form (You’re talking about a 2+ ton car with 127 HP / 121 TQ - figures that would disappoint in a Miata.)
Since the 24 valve motors were later fitted to the e34 chassis, with some baseline mechanical knowledge and experience you’re looking at a very doable swap which will open up doors power and modification wise. Even a stock m50b25 would give you not only a substantial power bump, but yield much better fuel economy and leave more potential to squeeze out with boost later on.

[Mrneau]

Thank you for your help sorry for the lack of knowledge I have but hoping to learn a lot on here! The car won't ever be registered it will be trailered to events and just a toy!

[bigsixe34]

Happy to give my 2 cents. You will learn a lot here. There are a couple of guys (Ross included^) much more knowledgeable than I that will save you hours and headaches.

[moroza]

Hello and welcome! You sure have a weird engine combo. Out of curiosity, why this car? A running US-market 525i can be found for less than shipping alone... does it come with a lot of extras, or have E34 supplies really dried up?

Ok then you have a couple logical avenues you could pursue.
Ross is probably right in his suspicion that it should run as is and isn’t because of a setup error. So just getting it to work would be the easiest. I can assure you however that “torque”, “speed”, and “power” will not be part of your vocabulary when describing its stock form (You’re talking about a 2+ ton car with 127 HP / 121 TQ - figures that would disappoint in a Miata.)

Oh they aren't *that* heavy. My M50 slushbox wagon is ~3470lb without fuel. With a lighter engine, trans, and body, I'd expect this 520i to be around 3300.

[bigsixe34]

You’re right - I overshot there. 1.5-2 ton.
In the power to weight department the touring is well on top though, which is telling. . .

[Mrneau]

BMW's in the northeast are rotted out. So west coast was the place to find a rust free car. They are about 2500 here with all kinds of rust and issues

[Mrneau]

I just picked up a 1998 M50B28 with 90k on it! Now I found out I need an oil pan from a 525i so it will fit. I ended up with motor and 5spd manual for $900. Any good advice on completing this swap?

[fo3]

That would be a m52b28TU which is OBD2 and dual vanos

Your options would be convert your car to OBD2 and get something to run the vanos system. Or do a cylinder head swap and put on a m50 head and keep the car OBD1 E: you'd have to get a chip for the OBD1/m50b25 DME for the extra displacement ).
I don't know much about what is in a m20b20 car so even keeping it OBD1 may mean spending a lot on OBD1 m50b25 intake, DME, chip, replacing sensors on the m52b28TU etc?

Maybe read/ask in the e30 or engine swap forums as they are where people are posting fitting m52bxx TU vanos engines into M20 OBD1 cars a lot. I've read about OBD2 swaps and piggy back computers to run vanos in those forums before.

2E: I know a poster here called tristan36 put a s52 into a m20 525i last year. I'm not sure if they still read this subforum but maybe ask them for pointers/difficulty level https://www.bimmerforums.com/forum/s...o-e34-s52-swap