There is a local RX3 for sale with a miled out motor and I was wondering if it is possible to drop a newer gen 12A in its place? Need new harness and ecu etc? Any help would be excellent!

~Jory

 

later 12a will drop straight in
and the mods needed are minor and very straight forwards

however it may require some simplification of the carb aux circuits
( the rx7 carb will have power valve,, coasting richer solenoid , air vent solenoid , auto choke and sometimes a position switch on the side depending on model )

you can get around most of that by simply retrofitting the rx3 carb and manifolds
( or by removing and blanking those listed aux circuits )
-- beware that some inlet manifolds extend down to cover the ACv port on the block,, some don't
and this will limit the swap around if the desired manifold doesnt,, yet block has ACV port


the rx7 engine will also have single dizzy and maybe electronic ignition
-- of which its very desirable to mod your system now to take the HEI coils and transistor dizzy
( there will be ample info on that method here if you search )

 

does the rx3 have dual dizzys?

 

in aus,,, where we get the 10a version,, yes
later we get the 12a version,, this is single dizzy,, points

- i suspect US never saw the 10a twin dizzy motor
but irrespective,, the 12a rx7 motor is and has been a very common retrofit
and the same rules apply

-- use the rx3 manifolds and carb if they will fit,, but keep the rx7 transistor ignition

if forced to use the rx7 carb and manifold
then you have to rig the richer and power-valve and air vent to a 12V IG switched source
- or remove and blank them to be in the correct failsafe mode


in aus and other RHD markets,,you may find the autochoke mech clashes onto the clutch master
-- in this situ the auto choke is stripped,, the mech flap and fast cam idle wired together and hooked to a manual cable


PS,, earlier the carb,, the more power it will make
( later versions up to about 1981 are jetted richer to suit thermal reactors and cost power )

 

Here's an image of the engine bay of the car, it does have twin dizzys as you can see! Shouldnt be too hard from what I can see, so little wiring in these cars it's awesome.

And heres just a picture of it in its entirety.