B35 head swap, couple quick questions

[RickSloan]

I just read thru a bunch of threads gathering what information i could.
Here is what im working with and what im doing

M30B34 635csi (in the car now, head gasket is going)
M30B35 Head on its way from funk
M30B33 Cam sitting in the garage, originally for the B34

here are my questions...
1. For the head swap, is a B34 gasket going to work?

Is it just a bolt on kinda deal? Do i have to match anything for the block and head? and will the intake plenum bolt on? Or do i have to port match the inlets on the head???

2. Should i bother swapping in the cam? Will i see a power increase? The motor will eventually see a SC, hopefully pushing about 15lbs at some point in the next year.

I think thats it... or at least all i can think of at the moment. TIA for any information!

[Brian D]

Pretty sure the B35 is the hottest stock cam available. Search at www.mye28.com , there's a lot of info regarding your questions. That's the best site I've found for M30 tech.

[euroshark]

The B35 is the hottest stock cam you can get BUT the B35 head on a B34 block is going to drop your compression quite a bit. If you are at 8:1 right now you will wind up around 7.2 or 7.3 if I am remembering the thread on mye28.com correctly...

I'd use a B35 gasket.

[LowR3V'in]

So a stock b34 will have 8:1 stock, and with a b35 head it'll drop it down
to 7.3:1?

[wildstoats]

The B35 is the hottest stock cam you can get BUT the B35 head on a B34 block is going to drop your compression quite a bit. If you are at 8:1 right now you will wind up around 7.2 or 7.3 if I am remembering the thread on mye28.com correctly...

I'd use a B35 gasket.

QFT. The value I heard quoted for a B35 head on a B34 block was a compression ratio of 7.45:1. That's super low even for forced induction. You would probably be better off using a B34 head. If you want to get creative you could swap all the valve train components from the B35 (cam, valves, springs) but that will require new valve seats to be cut in the head since the B35 valves are larger. Another option would be custom pistons. Expensive but then the compression ratio problem becomes moot. Then again I'm not really sure what your entire plan is so maybe I'm off base here. Just figured I would toss in some of the tid bits I've picked up from the e28 boards over the years.

[RickSloan]

ok so i guess i really should have read a bit more before ordering the head. I had seen alot about this swap and never saw any of this info until the last few days. Part of the reason i wanted to do it regardless is cause it will fit better in my engine bay.

I was lurking over at mye28 and i came a crossed a lot of what is being said here. So the compression will be to low for this to be a valuable upgrade with boost???

This motor won't be seeing any internal attention or boost for at least 6 months if not more. The cheaper and easier route for me would have been to find if my b34 head is alright, or get a b34 head from Funk, and install my 533 cam in that.

Thanks for the info guys, i think my plans might change a bit...

[JoeMadoo]

or get a b35 engine

[RickSloan]

i knew that was coming, but that is a little out of the question right now...

i need this car up and running by the end of the week

[e30_kid89]

I had a B35 head i was going to give away for next to nothing...

But then i was lazy and destroyed it because i forgot to take out the headbolts when taking out the rocker shafts....so i got a bigger hammer instead

It will be a lazy dog with the b35 head...
But its a straight bolt on. I would use the stock b35 cam.
Pretty sure you can use your intake over again but the ports wont match.


Details on S/C?

[RickSloan]

the SC is in the works. Currently we are finishing up a system for an M20 powered e30 and once that is all worked out we will start work on a very similar setup for the M30 with a bit more boost.

We are using a roots blower from a buick rivera and a pretty custom setup for everything else. There are quiet a few write ups floating around on similar setups actually

thanks for the input

[SpecM]

good luck robbie

from what I hear, I would stick with the b35 cam

[JoeMadoo]

the SC is in the works

^^^ nice, I've been wanting to see a S/C m30 e30.

[LowR3V'in]

That's super low even for forced induction.

Should be perfect for.... 30? psi. :)

[E30SPDFRK]

I have been planning a sc for a while too, but I'm going to use a Rotrex or similar centrifugal. How much boost do you plan on running?

[RickSloan]

we gotta see what happens with the M20, want to run about 8 to 10 lbs with that and with the M30 we want to aim for between 10 and 14