cylinder head compatibility

[Markos]

I agree most have newer heads, 82 and newer with original casting number. I would think matching chamber diameter and bore diameter would be key, 2.8 vs 3.0 and others.

Here is a pic of my 277 head. I used my iphone’s skewing features fo straighten out the angle. Pretty nifty.

Anyway, you can see that the 89mm bore of a B30 still falls outside of the combustion chamber. The 277 head was used on the B34 which was 92mm. So BMW didn’t care about going larger and having some flat material overhanging the cylinder.

An 86mm 2800 would be 1.5mm closer to the chamber, and you can see from the pic that it is getting awfully close.

 

[frogish]

The cylinder head I bought has number 1277358 on it. Getting it pressure tested tomorrow. The cam in it has marking 3 on it and 0697.
I just want to be sure it won’t be an interference issue with the piano pistons.

 

[Markos]

The cylinder head I bought has number 1277358 on it. Getting it pressure tested tomorrow. The cam in it has marking 3 on it and 0697.
I just want to be sure it won’t be an interference issue with the piano pistons.

This is the same casting that was on my CSI, which had factory piano tops.

 

[frogish]

This is the same casting that was on my CSI, which had factory piano tops.

That makes me comfortable to hear.
Also some weird marking at the back of the cam, 497 I think? Looks sketchy.

 

[westoz3.0csa]

I so hate how easy computers allow you to research hours on end and still come out no wiser

Ok, so now that I have researched myself into more confusion

Can anyone advise me on the following ....... My coupe is a Euro '74 RHD Carby car.

Due to a broken rocker and a threaded rocker lock nut, I intend to replace the head, which has been removed and is an '80 Date code so is not original and
so I don't need to keep it for 'originality'.

I bought a complete M30B30 engine from a low mileage (70K miles) '94 E32 730i about 6 years ago. It was running and I was able to do a compression
test and all Cylinders were 170 - 175 PSI.

On this basis I am/was hoping to 'just' transfer this head onto my motor.

However .... in the teardown I have come across some differences that raise questions .... hence the research and now confusion coz there seems to be
differing opinions on different forums!

It is a motronic engine ! and is a single timing chain version against the twin chain on my coupe.
The head has an '88 Date code.

So before I actually continue and separate this engine ...................

Can I use this Head on my car ?

Things I know I need to do .. but don't know if it is possible are ...

1) change the Distributor Drive adapter ... will it just swap over?
2) use the early upper Timing chain cover?
3) Bolt the Twin Chain Cog to the '88 Cam plate .... ?
4) use a Head gasket from an E32 730i ?
5) Will the cam in the '88 be OK ? .... I do assume it will be ... but ...!
6) I intend to keep the carby's ..... will this be ok?

Any advice on the Head suitability and anything else I should do while I'm there, will be greatly appreciated ........

 

[Baikallackierung]

I think your items 1-6 will go well, but have you compared combustion chambers? I can think of at least two scenarios to consider. The first is that your compression will be lower due to the late head having a bigger combustion chamber and the second would be that your pistons and combustion chamber could be a bad match. Mull it over while the specifics roll in from other members - hope this helps...

P.S. Does the newer head have a place for a mechanical fuel pump? Might need to run low pressure fuel pump to the carbs.

 

[Markos]

I’m no expert? but I know you will need to switch to an electric fuel pump. @Stevehose has a good carter rotary pump recommendation IIRC. You will also need to use your old timing cover to support the distributor and clear the timing chain. You will to swap the cam so you can have a more aggressive factory 272 cam, and the dual row timing chain sprocket. It’s possible that the ‘94 B30 has a 272, but most of the B32’s and B34’s were closer to a 260.

I’m sure @sfdon can set you straight.

 

[deQuincey]

I so hate how easy computers allow you to research hours on end and still come out no wiser

Ok, so now that I have researched myself into more confusion

Can anyone advise me on the following ....... My coupe is a Euro '74 RHD Carby car.

Due to a broken rocker and a threaded rocker lock nut, I intend to replace the head, which has been removed and is an '80 Date code so is not original and
so I don't need to keep it for 'originality'.

I bought a complete M30B30 engine from a low mileage (70K miles) '94 E32 730i about 6 years ago. It was running and I was able to do a compression
test and all Cylinders were 170 - 175 PSI.

On this basis I am/was hoping to 'just' transfer this head onto my motor.

However .... in the teardown I have come across some differences that raise questions .... hence the research and now confusion coz there seems to be
differing opinions on different forums!

It is a motronic engine ! and is a single timing chain version against the twin chain on my coupe.
The head has an '88 Date code.

So before I actually continue and separate this engine ...................

Can I use this Head on my car ?

Things I know I need to do .. but don't know if it is possible are ...

1) change the Distributor Drive adapter ... will it just swap over?
2) use the early upper Timing chain cover?
3) Bolt the Twin Chain Cog to the '88 Cam plate .... ?
4) use a Head gasket from an E32 730i ?
5) Will the cam in the '88 be OK ? .... I do assume it will be ... but ...!
6) I intend to keep the carby's ..... will this be ok?

Any advice on the Head suitability and anything else I should do while I'm there, will be greatly appreciated ........

some photos will certainly help, it is funny now everybody has a smartphone and very few post pictures (which (posting pics) is obviously in your benefit)

original heads as early 70s are very delicate and heat sensitive, due to long oval water passages) so they are prone to cracks, usually all engines had head replaced with 82 till 89 (small water passages)
heads are interchangeable (see the note on fuel mechanical pumps)

noone will discuss with you the originality of a changed head, unless he insists in running your car in the original tyres form 1974 or die ! if that is the case you know who you are dealing with and you probably have a way of considering his opinions and advices

keeping the zenith carbs is an excellent idea, they are amazing performance, and keep the originality; they can be overhauled and refreshed with new gaskets, and will last forever

carbs will be good with mechanical fuel pump, here the photos of your proposed new head will help as not all heads have the place for the mechanical fuel pump rod

no "need to switch to an electric fuel pump" in principle, it depends where you are and what you want to do...

double chain or simple chain no problem, the wheels, psrockets, and pinions are interchangeable, it is advisable to put double chain but you can live with the single one too


good luck