This is kind of a figure it out for yourself in a way.

I am going off pictures mostly. I haven't seen a list of what to look for or things to avoid.

Search out some of the Mini Cooper forums. Those have had some how to threads with great details about this build.

http://www.britishcarforum.com/bcf/sh ... OHC-FI-head-on-1275-block

Yes, there is no step-by-step guide. However there are partial guides such as post 61 in this thread.

Quote:The "a15 block mazda head" is referring to the Mazda 1300 DOHC head, which has valves too big for the A12. And if I understood correctly, requires the DOHC pistons (see post 61) which won't work in an A12.

However...
Quote:So the SOHC head will fit on A14. And you can bore an A12 out to A14 bore size and fit the A14 pistons in the A12. So the SOHC might work on an A12.

DOHC vs SOHC

Rob has built an early A12 using the early
Mazda B1 and B3 engine with 71mm bores

https://en.wikipedia.org/wiki/Mazda_B_engine#B1

Robs 8v A12 was to be fitted to a 1000 someday

B1 & B3s see 8-9k rpm @ speedway / circle track

Sooooo... There isnt a DOHC for the A12 that doesnt require it to bore'ed ALOT ?

As the A12 that sits in my B210 ad the moment is the only one i've got, I would like to make it, the best it can be :)

But I live in Denmark, so turbo, isnt going to be easy to get legal, but headswap efi ect is OK..

And compared to fx a port job(which cost alot around here), this would be a better project :)

The K1200RS BMW bike head will fit the A12

http://twinkam.co.uk/epages/191f6b26- ... a0c9099c1/Categories/2/12

Quote:

Like bolt right up?

Or do they have to go through those guys for a rebuild / conversion ? Caus they are fairly cheap on ebay, but through them its a little pricey ?

Nothing is bolt right up. With all of these DOHC setups you have to reroute oil and water passages, and block some off on the engine casting.

All of them take some in-depth work and massaging.

Would it be better to try and get a a14GX head ?
Or wold I loose too much compression and therebuy not be worth it? I guess you could machine a cupple of mmm. of it to retain compression but get much better flow?

I have an A12 factory head with some mild port work and that is what I am going with on my Super charge build. I have to shop a new CAM.

The DOHC project is on an engine dolly, and will most likely sit as a display even after it is finished.

Its up to you on what direction you feel is good for your enjoyment.

You won't lose any compression if you change A12 head for A14 head. But A14 head only make 85 HP maximum unless extensive porting is done. The DOHC 16-valve head makes 104 hp bone stock.