Hey guys,

I recently purchased an MG with a later model A14 swapped in. I came across this site and it has been incredibly helpful. I just had a quick question about alternators, as I'm trying to make sense of the previous owner's setup. In referring to the alternator tech wiki page, I'm looking at the 1974-up configuration.

What I am looking for is a direct replacement alternator that is internally regulated. I currently have the F and N wires wired correctly edit: totally wrong :) (on my car F goes to the warning lamp and ignition switch, and N goes to the automatic choke relay,) but as there is no voltage regulator, I'm worried about cooking my battery. (I get around 16v at the battery terminals under higher rpm)

From what I can tell from the Tech Wiki alternator page, I'm looking for an alternator from a 1978-1979 Datsun 620 Pickup. However, I'm worried that wiring will not be the same. Is there a replacement alternator with F-N wiring that is internally regulated. Much thanks for your help

Is it a hitachi alt you are running?

Hi and welcome to the club. How do you like the A14 engine?

The later 620 alternator is a direct swap for a 1200 (A12 engine). The A14 uses a larger alternator than the 1200/620.

All FN alternators are, by definition, for use with external regulator. But there is a an internally-regulated A14 alternator with LS wiring. It uses the same T-connector: 1978-1982 internally regulated A14 alternator

But you have it wired incorrectly. FN type should be: F goes to a voltage regulator, not directly to the warning lamp. LS type can be connected directly to the warning lamp, but it is the L terminal. So you'll have to re-do the wiring (all two wires).

I don't believe so...its just the one they sell at parts stores like Autozone that looks like the stock one. It is supposed to be an externally regulated alternator, but I don't think the previous owner wired a regulator in. Only connectors are the battery, and the F-N T terminal outputs.

I'd have to admit, the A14 makes a pretty good fit in my car. I've been pretty happy with it, just unfamiliar. So I could get a 78-82 210 alternator that is internally regulated, but it would be LS wired?

So if I understand this correctly, L will go to my indicator lamp (which is also connected to the ignition switch) and S will go to..? Can this connect to the electric choke?

Sorry my questions are probably pretty dumb...I'm terrible with wiring

FN type must use an external regulator, or you'll burn up the battery (16V will boil a lead-acid battery).

See my previous post.

Just ran down to the store and picked up a Hitachi internally regulated amp for a 1980 210.

Can I run the wire from the electric choke relay to the "S" terminal on the alternator? Or should I probably just wire the choke to a switched 12V? I guess the only downside to this would be if I left the key in the ignition too long before starting. Thanks guys

I believe the T-connector for FN is wired the opposite of T-connector for LS -- so be careful. L to lamp and S to always-hot. Alternatively connect S to IGN hot.

Your MG has an auto choke relay? I do not know how it is wired. On a Datsun with internally regulated alternator, the L wire goes to the choke relay. But then the relay is wired differently from a Datsun with FN type alternator.

People sometimes think any alternator with a two-wire T-connector are FN Type. But not alll are.

On some rebuilt alternators, the FN letters or LS letters have been bead-blasted off, but on originals they are there:



This Hitachi LR unit is a one-wire alternator. The only wire needed to the wiring harness is the L wire. The S wire can be connected to BAT on the back of the alternator. Just like GM's famous "1-wire" which actually has four wires.

Ok great. Thanks a ton for the help. I will put it in today.

As far as my MG and electric choke - no it didn't have it originally, but the previous owner included a Weber 32/36 (I think) carb that has it. So I've got a choke cable on the dash that goes to nowhere