M30 b35 head or b34?

[Csmitho777]

Hey guys I am getting M30 painted and ready. I have a m30b35 from a 1990 535im that i parted out. The car ran before I pulled the engine but had 170k on it. I took the head in last week and the machine shop found it was warped beyond repair. I found a rebuilt head for a good price but I don't know which one it is heres the link

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=190193229891&_trksid=p2759.l1259

Will it be stupid to put this new head on a old bottom end will 170k on it?

Also is the b34 block with b35 head the best setup for a turbo? but not for N/A because I plan on turboing but not for a while after the swap.


thanks alot

Colin

[george graves]

I don't know the answer sorry. But If I wanted to find the answer, I'd head over to mye28.com.

HTH

[Erik j]

That is a b35 head, notice the 3.5 stamping on it. the 35 has larger valves and a better cam in it.

[euroshark]

Other heads (B34, B32, M90) heads sometimes also say 3.5 so that's not the best way to identify it. Look at the casting date, or measure the valves, B35 valves are 1mm larger than the rest.

Putting a new head on an old bottom end is not a bad idea, it will not appreciably accelerate wear on any of the parts.

The B35 head on a B34 block is "better" for turbocharging, as it reduces the compression on a US spec B34 block from 8:1 to roughly 7.2:1, but it is pretty unnecessary since 8:1 can safely support 15+ psi with an intercooler. The only real advantage is the bigger valves, and maybe the slightly different combustion chamber shape, but overall I think it's overrated. Plus, driving a 7.2:1 B34 until you turbo the thing is not going to be a whole lot of fun... think of somewhere in the 165 to 175hp range most likely (they only made 184hp stock in US trim).

And just for reference, the B34 and B35 are the same size, 3430cc. Also, according to all of the parts sources, the B35 cam is the same as the Euro B34 cam - 264 degrees. The "hot ticket" would be to get a new early 533i cam for $190 or so, as they are 272 degrees and fit right in (with the ignition rotor adapter of course).

[Justinian]

When you say early 533 cam could that possibly be from a early 633 like a 78 as well?:-)

[ldsbeaker]

Good info.

[euroshark]

Yes, any 533 / 633 / 733 cam up to 4/84 should be the higher duration cam. If you need the adapter for the motronic distributor drive (if you go with a '78 cam) let me know, I have a few.

When you say early 533 cam could that possibly be from a early 633 like a 78 as well?:-)

Having said that, IE sells regrinds for right around $200. I think they have a 284 and 292. Regrinds have a bad reputation for some reason, but realistically, most regrinds are stronger than the stock cam. We sell regrinds where I work and the metal on the lobes is about 40% stronger than stock!

[Jean]

Other heads (B34, B32, M90) heads sometimes also say 3.5 so that's not the best way to identify it. Look at the casting date,

What are the date ranges for the 3.5L with bigger valves ?