Euro 635

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WALTER

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Gents,

I have 'Euro' 635i ('79) engine that I might purchase to do a swap with my 3.0 motor. I have a few questions that I hope you can help with:

1. How can I identify this as a 'Euro' engine?

2. Does the Euro version of the M30 mean that it is actually designated an M90?

3. Is this engine rated at 208 or 218 (I've seen both in my research)?

4. Besides the higher compression and bhp, are there other advantages over a later M30b35? Any disadvantages (premium fuel, etc)?

Anyone out there running this swap that can tell me their experiences would be appreciated as well.

thanks,

Walt
 
there is a flat spot on the block by the starter- look there for the last 7 digits of the vin #.
input those numbers into the realoem page and you will get production date and type of car and engine. http://www.realoem.com/bmw/select.do


The M90 pistons are extra big-93.36MM for the 93.4 bore.
http://www.realoem.com/bmw/showparts.do?model=6831&mospid=47183&btnr=11_1665&hg=11&fg=20

a 1979 Euro engine will be a 3.5 218 hp medium compression engine- known as the M90 engine.

downsides- are availability of headgasket and the fact that the m90 engine is not a rev engine but more of a low-end torque engine. Some people say that the headgaskets are prone to failure.

all three candidates for the coupe upgrade use 264 cams - the M90 is Jetronic and the Euro dirty 10:1 compression and the b35 are Motronic.

Always verify the cam- I bought a euro spec dirty engine last week with a US 260 cam installed. Look for white letter K between 5 and 6, a K stamped in the end of the cam or the red and green stripes.

The b35 has bigger intake valves and bigger exhaust manifolds. It also uses double valve springs. BMW also added a tensioner for the oil chain and a better starter.

I spoke with Ray Korman last week and he doesn't like the euro spec dirty engine because octane levels have dropped to 91 octane from 93 octane.

Carl Nelson uses the m30 b35 engine for good reasons- he is a smart guy.

I have built and installed 5 Euro spec engines in the last six months - I would think the least disirable of the 3 models would be the M90 Jetronic version. That said - it would still be a fine engine.. You should consider port and polish and a Shrick cam too :p

Toss up for the other 2 but definitely go with the B35 Motronic 1.3 adaptive unless you go MAF or MAP.
 
It makes a good base for a stroker 3.7L using a B35 crank with a M90 bottom end. The best "hybrid" I have seen used a M90 block, custom rods, custom pistons, and a B35 head. 3.7L, 9.5:1 CR, spun quite nicely.

Rods- ~1000$ US
Pistons- ~1000$ US

The rest you can get for dirt cheap. The tricky part is getting a good engine tune at that point. I'd probably go with a Motronic 1.3 base and a Miller WAR chip or MegaSquirt.
 
My 80 635 M90 euro has factory installed Motronic, which was installed on the May built of 80 cars, on. I am also running a Schneider 284 reground cam and 10:1 pistons as well as a lot of port work. I haven't fired it yet, but am anxious!! Haed gasket was easily obtained by the machine shop
 
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