MA12 engine where a MA10 was

[martha]

Hi,
I have a 1991 K10 micra with the 1.0L MA10 engine and 4-speed gearbox. The MA10 engine needs a full re-build (new piston heads, bores scored, etc.) and currently I'm exploring the option of putting in a replacement MA12 engine while I take my time with the re-build of the original MA10.
I gather from the discussions here that it is a fairly easy straight swap, but I'm getting concerned and confused about the MA12 having an EGR with an ECU (an exhaust gas re-cycler with an electronic control unit? correct me if I'm wrong here) and I don't think my MA10 currently has this. Can anyone explain?
Any help greatly appreciated!
Gregor

P.S. the reason for considering the MA12 over a straight MA10 swap is that the car is now in Sweden and MA10 engines do not seem to be available from scrap merchants. Perhaps the MA10 was never sold here??

 

[mckenziecz]

i think it was only the later version having EGR and ECC, but it shouldn't matter whether the engine was originally EGR or not as soon as you use the original coil, dizzy, carb and inlet.

 

[aLLeKs]

i think it was only the later version having EGR and ECC, but it shouldn't matter whether the engine was originally EGR or not as soon as you use the original coil, dizzy, carb and inlet.

Exactly.... use all your original stuff and just use the new block and head. It will work fine and you don't need the egr, ecu and so on

 

[superls]

what id do is if i were you, unbolt the gearbox, inlet manifold, exhaust manifold and dizzy of the ma10 and bolt it on the ma12 then it will fit and work no problems at all.

 

[mckenziecz]

to be honest, why dont you get the 1.2 rebuild that, and then swap it over? you gonna get more power.

 

[porkpie700]

I swapped my MA10 for an MA12. The 12 was an egr/ecc set up in the scrap car but didn't have it's distributor so i couldn't use that set up, otherwise i would have. What i did was to take the exhaust manifold, inlet manifold, carb, distributor and airbox from an MA10 and fit them onto the MA12.
Before fitting the carb i reccomend cutting off the anti-tamper cap on the mixture screw because you will need to adjust the mixture as well as the timing to get it running right, which might take a full day of making adjustments and testing.
I would reccomend getting a propper non ecc/egr MA12 carb to use instead of the 1.0L carb, as they are jetted differently and although the 1.2 will run with the 1.0 carb, it doesn't run quite as smoothly.

If you get stuck on something or if you decide to use the egr/ecc setup then this manual is a huge, huge help.

http://www.supermotors.net/registry/7742/23795-2

 

[aLLeKs]

I would reccomend getting a propper non ecc/egr MA12 carb to use instead of the 1.0L carb, as they are jetted differently and although the 1.2 will run with the 1.0 carb, it doesn't run quite as smoothly.

even if it sound unlogical, the ma10carb has bigger jets

 

[superls]

the ma10 carb does have bigger jets, i ran an ma12 engine on an ma10 carb for 12-18 months with no issues what so ever.

 

[Ed]

will work fine the power difference between them is so small that it should all just work.

 

[porkpie700]

Well all i would say is use a 1.0L carb if you want to but if you can get a 1.2 carb then it's best to use that. I've driven the egr setup and it was very smooth. I've driven the non egr 1.2 and that was very smooth too. And for 2 hours every day i drive a 1.2 with a 1.0 carb, not quite so smooth anymore when compared to the 1.2 with the correct carb on it. I found all 3 to have equal power in every respect, just a different exhaust tone.
But all that said; this is my experience and my oppinions, which may or may not be what you or others encounter. So really it's just down to what you want to do and what your budget will allow you to do. Remember to change the rear engine mount to a 1.2 mount, they're different as the MA12 has additional supporting brackets to hold it in place. You may also want to change the fan-belt pulley for the MA10 one so that you don't have to change your altinator for the tracked belt type (assuming that your donor engine has come from an egr/ecc set-up car).

 

[martha]

Thanks everyone for the hints, tips, and explanations. It looks like I will at least be going down the route of creating an engine based on a MA12 block and head with, depending on what I find from scrap merchants, various options on the carb front! You've certainly helped explain what I will find on the different engines likely to be available (Y)
As I mentioned in the P.S. I now have the car in Sweden and it needs to sit its re-registration tests soon (it's originally a UK car whose MOT expires in December, it must get re-registered before then!) which is why I need a relatively quick-fix and am considering the engine-swap rather than re-building the original engine right now.
This weekend I'm going to go scrap-engine shopping so I'll keep you all posted.