info about head

[Marco]

Hello,

Can anyone tell me if a cylinder head of a e24 3.0 cs (carbs) 76 can be dropped on a e9 3.0 csi 73.

My cylinder head is busted and i can get a nice head but i don't know if it is exactly the same, so help me out please.

Greetings, Marco

 

[Orangener]

Hi Marco!

No, definitifely not !

Because of the design of the "Dreikugelwirbelwannenbrennraum", tripleballswirltubcombustionchamber, the carb-version has another compression and other pistons, with a "pitch".
I know that, ´cause i had the same problems a few years ago....

 

[Marco]

Thanks,

I didn't know that.

I have now 2 options go for an orignal 3.0 csi engine or 535i engine what shall i do ?

Greetings,

Marco

 

[Bill Riblett]

I disagree.

The heads are the same except that the carb head has a hole for the fuel pump drive rod.

Differences in compression came from different pistons.

The heads changed over time, but mostly to make them less likely to crack. This started in 1980. It wasn't until 1988 when larger valve were installed that there was a significant change.

2 x 72 3.0CS
79 633CSi
86 635CSi

 

[Orangener]

I checked this once more, Bill, youre right.

On the cylinderhead should be the cast-number

#1 250 019 or #1262243 or #1250015 :

than it fits to 3,0 liter E3 + E9 + E12 + early E24. Valvediameter 46 in / 38 out

With #1 277 358 or #1288086 :

than it fits to E23 + E24 +E28 (150-218PS)2,5l-3.5l---->Valvediameter 48er in / 38out

I´m sorry Marco, for the confusion i made!

 

[velocewest]

Bill is right. All M30 heads have the same compression chamber size and shape and valve size up through the M30B35 engines installed in e34 and e32 cars in late '88.

On a later head from an FI engine, the boss for the fuel pump will be there, you just need to drill for the pump rod and drill and tap for the mount bolts.

 

[Daxklynsmith]

Bill is right. All M30 heads have the same compression chamber size and shape and valve size up through the M30B35 engines installed in e34 and e32 cars in late '88.

On a later head from an FI engine, the boss for the fuel pump will be there, you just need to drill for the pump rod and drill and tap for the mount bolts.

Or fit an Electric fuel pump. I fitted a facet as a spare inline.
What I did have to do when I fitted the E3 3.3l head was to grind away part of the port as the pistons on the E3 were different to the flat pistons on my 3.0 engine .

 

[Marco]

Thanks,

It's a CSI so i don't need to drill holes

I'm gone get the head and fit it i let you know when it runs again.

Greetings,

Marco

 

[gazzol]

Would I be right in assuming that it would be possible (after changing the camshaft) to put a post 1988 head on a M90 (E12) block or am I mistaken :?:

 

[velocewest]

Yes it will work, but the combustion chambers are larger so you will lose some compression. I can't recall all the numbers exactly, but I think the b35 heads will drop compression about .8 to 1.0 -- so a 10:1 M90 would end up 9:1 or close.

 

[gazzol]

Yes it will work, but the combustion chambers are larger so you will lose some compression. I can't recall all the numbers exactly, but I think the b35 heads will drop compression about .8 to 1.0 -- so a 10:1 M90 would end up 9:1 or close.

Thats a very interesting piece of information!!! Acording to the information available to me the E12 M535 (euro spec) was 9.3:1 C/R and I was toying with the idea of turbocharging my car, now I know how to lower the CR without resorting to custom pistons or deck plates.

 

[x_atlas0]

Yes it will work, but the combustion chambers are larger so you will lose some compression. I can't recall all the numbers exactly, but I think the b35 heads will drop compression about .8 to 1.0 -- so a 10:1 M90 would end up 9:1 or close.

Thats a very interesting piece of information!!! Acording to the information available to me the E12 M535 (euro spec) was 9.3:1 C/R and I was toying with the idea of turbocharging my car, now I know how to lower the CR without resorting to custom pistons or deck plates.

You could also use a thicker head gasket to lower the compression. Although honestly, with the modern computer controls available and a good tune, there is no reason to lower the compression further. There's been a few M50s (10:1 CR) at 14 psi for years with no problems. Unless, of course, you plan a monster build.