Hello,

I've owned my 1200 since 1997, but now it's time to put extra power under the bonnet so i gone start the project off putting A15 Engine on my 1200.


Many off you have already help me with some tips but here are the setup i'm preparing

A15 Block
A12 M30 Head (i don't have A14/A15 head)
H89 Head (now i have one)
A12 Flywheel
Octane to use 95 or 98
Combustion Chamber of the M30 head = 27cc

To do List:
- lightweight flywheel from A12 with 5,1Kg -> Done
- A12 Ported Head Don't need anymore
- Double valve Springs
- Worked Camshaft
- Single Weber 40 ou Bike Carbs
- Extractors 4-2-1
- Electronic Dizzy
- ...

What do you think off it??

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alright you will also probably be wanting an electronic dizzy for it aswell to give you some better spark and a nice exhaust to compliment your extractors... the a15 head would be about the same as the ported a12 one and you can always port out the a15 one aswell.

It's good to hear man. Your plan is similiar to mine. And I would have to agree with popo an electric dizzy is a must for your list. Also i went for a 32/36 dgv weber. I was told it allows decent economy if you drive nicely and the extra throat for extra power at full throttle.

I would love to hear what you think of the head option when you get this baby running as I was planning a ported a12 over the a15 stock.

Does the A12 M30 head have the large Oval intake ports, or the regular Round Port design?

The A12 oval ports are bigger than A14/A15 oval ports and require a special larger manifold.


Use a 4.375 differential and an A14 5-speed. Any of them will be closer ratio than the Datsun 1200 4-speed, but still provide good starting acceleration.

popo1200perth an electronic dizzy has already been investigated, just have to find one from a old Ford Fiesta, thanks for the appointment.

Aegis the decent economy is not relevant, because the street utilization is just in the meetings and weekend rides, but its good to know.
The A12 head is my biggest doubt but A14/A15 or GX heads are not easy to find in Portugal so is the only way to go.

ddgonzal the A12 M30 head is Round Port design unfortunately, but mine is a little bit ported.
4.375 differential and an A14 5-speed isnt easy to find in Portugal too, just finding on ebay or forum all over the world and the taxes in here are unluckily high for the imported parts, let's see what i can do.

Thanks all off you for your feedback

hi guys sorry to half hijack the thread

to use gx double valve springs do you get the new valve spring seats fitted to the head and then use double valve springs with matching retainers?
or is there more to it?

will the double valve spring seats fit any head?

very thankful for any help

yes. for GX springs, there are seats and retainers to go with them.. :)

ok thanks dundee

couldnt exactly understand bprojects english :P

Here are my lightweight Flywheel with 5,1Kg that arrived last week
Before and After

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I've measure the combustion chamber on the head, here are the photos

And with the help off BIGE getting the other measures i get a Combustion Ratio off 9.4:1 with a stock head gasket. What do you think should i send the head to machine it and get a Combustions off 10.4:1??

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