Hi, i'm new to the carbs world and would love to go twin on my stock a12 1200 coupe.

I'm read the page here about them but didn't find my answer..

Can i use a twin carb from any other car model and put it on my datsun ? If yes how do i know which one will fit, like i said i'm new to that world and don't know anything about them ..

For exemple someone here is selling old volvo that i think use SU twin carbs ...

thanks !

Hi.

i think volvo twin su is too big for a12. I'm with L16 twin su on my a15. running little rich. but overall is okay.
Experts advice please.
My friend is having a12 round port weber manifold. if you want i can ask him if you think it is worth the shipping..

I'm a little tight on buget right now, i'm taking informations in case i see something here and cheap .. but thanks !

It's an interesting question. The Datsun twin Hitachis are relatively plentiful, maybe that's why no one has written up what it takes to make SUs work on a 1200. There are different models of SU (two bolt, four bolt, etc), different sizes of SU, different type (emissions, pre-emissions) then you'd have to work out the throttle linkage, etc. Which several have done, so we know it's possible

Oh ok .. i don't know enough to start looking for other model of carbs then.. do you know a place where i can find more information about them ? Thank you

The old Volvo carbs will always be available. Id look for a twin-carb Datsun manifold. Once you get that, then go get some Volvo carbs to bolt on

Lynx D1000 fits standard A12 engine and all types of SU carb (4-bolt, 2-bolt diagonal, 2-bolt vertical)



Datsun factory manifolds, two-bolt diagonal. Fit only A12 GX engine. Will also bolt to A14/A15 cylinder head

Nice, thanks !

Do the size will change something ?

And you were talking about type, it won't change anything whatever type i found ?

Just to clarify things; is the motor equipped with oval port head or round port head. You are going to need a twin carb manifold and dependent on what style cylinder head you have that may be an additional issue.

Tom

Almost sure the round one. Will check to confirm tomorrkw

Quote:Yes, whatever SU you get will need to be rejetted -- none of them are jetted for the A12 engine. It'll run on the car (all gasoline engines require the same air/fuel ratio) but the dynamic characteristics change with every engine type (mainly throttle/acceleration changes, and fine tuning the a/f ratio). On an SU this means changing the needle jet and the dome spring

For example:
* A12/A14 factory twin carbs use the light dome spring
* All other Datsun factory twin carbs use the heavy dome spring
* SUs use one of many dome springs

Dome Spring



Jet Needle (also visible in previous photo)