They use 4 valves/cylinder which, along with the cylinder head design, helps the engine flow more air/fuel mix which equals more power.

ahhh o.k., i guess i could have figured that if i thought about it more cheers

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Yeah, but being lazy and asking questions is easier!

I have now compared an A15 gasket to a BG B6 head and can confirm hat it will bolt up, a lot of the water galleries line up.
I would weld up most of the oil galleries and run external oil feed and return, the biggest problem i can see is that the valves of two and four will hit the top of the block because of the pairs set up of the datsun.
Maybe pockets could be put in the block for clearance?
Some of you have mentioned offset boring of blocks in the past, can anyone explain this in more detail (specifically what has to be done to the crank and rods to allow for the offset.

Cheers

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A mate of mine is having this done to the engine out of his charger. Basicly, what they do is they ultrasound the block, and then adjust the alinment of the boring tool depending on the core drift of the block.

Chris

P.S I hope I haven't confused you too much

Damn my impulsiveness !!! I couldn't wait until after the silly season and have purchased a s/hand BG B6 head from a Mazda MX5 (NZ rwd model)

I have shown it to a mechanic friend of mine who has given me a lot of help in the past and he is not very happy about it (because it looks like it will work out nicely and he realises the problems are now our problems).

I will keep you all informed of the progress !

P.S. Does anyone know whether the cylinder deck height of the A14 and A15 blocks are the same ?

P.P.S. The bores are the same right ?

Sorry one more, the A14 has a steel crank right ?

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Yes they are same, I once made A14 with A15 internals, only mod needed was cut block little bit to make room for connecting rods, those block strenghtens were only differences I found.

Something that is worth keeping in mind with the B6 DOHC head conversion is that the Mazda B6 has pistons that sit proud of the top of the block where the Datsun A series pistons are flat with the top of the block. This will mean a reduction in compression ratio if you're going to use the standard datsun piston setup.

I'm planning on mocking up the engine using an old A12 i've got, but eventually fitting it to my A15 which currently runs 10:1 compression I will measure the compression ratio of this combo, but I am actually planning to turbo charge it using the 4wd 323 turbo and an MX5 (RWD) injection manifold (eventually)

matt
what did you mean by this?

Damn my impulsiveness !!! I couldn't wait until after the silly season and have purchased a s/hand BG B6 head from a Mazda MX5 (NZ rwd model)

what the story with rwd mx-5's, do they have same motor?