m30 experts please

[mikebloco]

So I've been trying to hunt down an m30 in good shape to put in my e30 and this whole time I was looking for a b35, but kept finding a crap ton of b34's. Then it dawned on me that they both have the same 3,428 cc displacement. So the only difference was compression ratio??? Is there anything else? I guess my plan is to get a b34 now but is there anything I should get from the b35 "model". My goal is to just try and make around 220 whp na and then eventually I might turbo it.

[ManSalad]

I'm no expert but from what I've read, the b35 is definitely stronger hp/torque wise but the b34 block is more durable for boost. As far as interchanging some b35 parts into the b34 to get the same power as a b35, I've read that it's easier to just get a b35 in the first place than trying to make a b34 perform like a b35.

[mikebloco]

Your name rocks lol. I thought the only difference was that the U.S. cars had catalytic converters and a lower compression ratio. C'mon m30 people help

[totheredline]

I had exactly the same dilemma as youre having. B34s everywhere and no B35s in sight. I personally went with the b34 because I found one for dirt cheap. I think I paid like $80 for it. I threw some B35 pistons in it for 10.3:1 compression.


there are TWO versions of the M30B34 (DO NOT CONFUSE the M90 with the M30b34) the US spec 8:1 green B34 and the euro 10:1 dirty b34. Dirty B34 has piano top pop up pistons while US has dish pistons. The euro motor also has a hotter cam and dual valvesprings, bigger injectors. All B34s and B35s have an 86mm stroke and 92mm bore.

The M30B35 was the last iteration of the M30, Key differences from earlier M30s

-Light weight block casting. (how much lighter I couldn't tell you)
-different head with larger ports and 47mm intake valves (vs 46 on previous models)
-combustion chambers are gas flowed and have slightly more volume than the older models (soo B35 pistons in b34 raise compression)
-double valve springs and a 264 duration cam from euro 10:1 "dirty" m30b34
-revised coolant flow
-motronic 1.3
-new pistons for 9:1 compression
-better flowing intake and exhaust manifolds.
-front sump oil pa with different pickup.
-different oil pump chain tensioner and oil pump gear for higher flow.

If you compare the head flow between the b34 and b35 the difference is very little. Im willing to bet my hand ported B34 head with 47mm valves will easily outflow a B35 head. Im not sure what kind of power its making yet but its very healthy and sounds godly. I also have a custom billet cam, double valvesprings, rocker locks, chromoly retainers and IE HD rockers I can safely rev to 7300rpm. The rotating assembly is also fully built, balanced and blueprinted. Where M30s shine is their torque. They drive A LOT like an American v8 especially with a 3.73 LSD behind them. I got a ride in a B35 swap sedan with a 3.73 and it was life changing. Stock b35 is a great street engine. They can be made for moderately high rpm however. The valvetrain is what holds it back. The stock springs that hold the rocker arms in alignment are not strong enough. rockers slip off the valves at higher engine speeds and break. This can be fixed with rocker locks. They are also an oversquare engine and the rod ratio is pretty good so even with the longer 86mm stroke of the b35 b34 lends it to be more rev happy then you might think.

HONESTLY if youre in for a budget build. grab a b34. get a b35 intake, oil pan, and pickup and maybe a b35 cam, a chip and b35 injectors and call it good. you'll make slightly less hp but the b34 will last FOREVER. The lower compression is easier on parts and you can run shitty gas through it. ANDDD you can go turbo later! Honestly that's what I wish I did. I would have saved a lot of money. oh yeah, M30s are expensive to build N/A. E28 guys will tell you turbo or GTFO. I didn't listen, but I will say Im very happy with how my build tuned out. GO FAST. No drama.


I could go on for a long time about M30s. One rock solid powerplant. HERES SOME REAALLY GOOD LINKS

http://www.mye28.com/viewtopic.php?t=109334

http://www.firstfives.org/faq/cylind...r_head_faq.htm

http://www.mye28.com/viewtopic.php?t=11795

http://www.mye28.com/viewtopic.php?t=51939



http://www.bimmerforums.com/forum/sh...450-M30-vs-M90

AND SOME INSPIRATION

https://www.youtube.com/watch?v=tqlIUd0jyjI

https://www.youtube.com/watch?v=kq6pr1XRgvI

https://www.youtube.com/watch?v=5zYZFSmxtqk

https://www.youtube.com/watch?v=GmgleKls0AE

https://www.youtube.com/watch?v=CDjndZor-dA

GOOD LUCK

[mikebloco]

Now thats what im talking about. Thank you. How do can you tell the difference between a the newest iteration and the rest?

[totheredline]

Valve cover is one way. B35 says "BMW" in big letters and the B34 will have a roundel. B34 will say 3.2/3.4 on the intake manifold while the b35 will say 3.5. B34s also have a coolant pipe that comes out of the back of the head towards the drivers side of the car

[mikebloco]

Gonna try and find a b35 or a complete car for the right price. Really trying to stay BMW but a 1j sounds nice too.

[EatsHondas]

M30 all the way, no jap motors. It's a very easy swap. No custom driveshaft, no cutting shift linkages, no wiring. All OEM parts.

You know you don't want to pop your hood and see TOYOTA.

[curtis_luu]

^

[mikebloco]

Lol Toyota and BMW are my 2 favorite auto makers. I've had 3 corollas and a supra that I built the motor in. They were good cars. I got the e30 for a change and then I fell into a chasm that is the euro world. I've been looking hard but I can't for the life of me find an b35 motor for sale that has less than 200k on it. I want to start with a not so abused motor. Found 2 b34's with 108 and 116k on them. The 108K one the guy wants 850 for and I still need to inquire about the other.

[mikebloco]

Talked the guy down from 850 to 500 because it's the b34. 108,000 miles is pretty nice though. It's out of his e23 L7 which had bad electrical issues so he's parting out the hole car. He also said before he pulled it he just did the head gasket, rocker arm group, and valve cover gasket because one of the rocker arms was bad. Says he has receipts from Turner motor sports so it seems legit. I'm gonna go check it out some time at the begining of next week.

[mikebloco]

So if it really is a b34. Couldn't I just deck the block to raise compression a point and bolt on a b35 head from bimmerheads when the time comes. Thats what the plan is so far. But the swap probably is going to happen for awhile. I'm gonna need to collect parts for a bit. I also want to do a 5 speed swap when I do the engine swap.

[mikebloco]

He sent me a picture of it and I can see the casting number on the head. 1277358
Correct me if I'm wrong but isn't that casting for a b35?

[mikebloco]

Made and adult decision and instead of buying that motor I bought suspension parts. No sense in putting more power in a car that can't fully handle it. My shocks and struts were toast so I ordered billy sports all around and H&R race springs. Once thats on I'll figure out what camber plates to get. Thinking about the IE street and track ones. My top hats are fine but I don't feel like wearing out my tires even faster.

[wannaBMthree]

Made and adult decision and instead of buying that motor I bought suspension parts. No sense in putting more power in a car that can't fully handle it. My shocks and struts were toast so I ordered billy sports all around and H&R race springs. Once thats on I'll figure out what camber plates to get. Thinking about the IE street and track ones. My top hats are fine but I don't feel like wearing out my tires even faster.

Good call, another thing I'd recommend are m3 offset CAB's. And RTAB's if in the cards.