View Full Version : Festiva Alternator conversion!!

05-05-2011, 09:29 PM
Once again I've relied on my memory and it let me down! A "fiesta" alternator is a common conversion but I ordered a "festiva" alternator instead.
Great little alternator that will take up very little space but I'm not sure of the wiring.
It has the standard hot lead and the 2 spade's that form a "T" and then a separate spade that I have no idea of.
Have any of you fitted this alternator?

Appreciate the help!


05-07-2011, 10:34 AM
From stuff I saved. Google Muenchausen's Garage

There is plenty of information on the net regarding alternator conversions for British cars. It's a common upgrade. I found the information at Muenchausen's Garage to be especially useful. In particular, the recommendation of the Bosch 13107 alternator, designed for 1978-80 Ford Fiestas, was spot on. This is a 55 amp alternator, which should provide all the current anyone with a bugeye Sprite could wish for; is inexpensive; and fits the Sprite almost perfectly. This is the unit I used.
Electrical Installation
The alternator has two 3/8" spade lugs marked "B+." Either of these is connected to the car's electrical system through a length of 10-gauge stranded wire. The old, mechanical regulator is no longer needed. The connections to the electrical system are as follows:
1. The wires from the A and A1 terminals of the mechanical regulator are tied together and connected to the wire from the B+ terminal of the alternator.
2. The wire to the F terminal of the regulator is disconnected and taped.
3. The wire from the ignition indicator light to the D terminal of the regulator should go to the D+ terminal of the alternator; the other wire to the regulator's D terminal, which went to the generator's field coil, can be taped and left open.
4. Any wires to the regulator's E terminal are grounded to the chassis at any convenient point.
The unused terminals on the alternator are insulated. A good method is to use a piece of shrink-wrap tubing. All unused wires dangling from the harness are tied out of the way, so their terminals do not accidentally touch something and create a short circuit.
A connection diagram is shown below:

Muenchausen recommends using two wires from the B+ to the car's electrical system. I suppose this can't hurt. However, invariably, in such arrangements the resistance of one of the B+ connections is a few hundredths of an ohm higher than the other, causing one wire to carry most of the current. In the end, I chose to use both spade connections on the alternator but a single B+ lead. 10-gauge wire is easily good for 30A, and I can't see the current, in this car, ever being any greater than that. The pictures below show the connection to the alternator and near the regulator; I plan to remove the old regulator, although it still appears in the picture.

05-08-2011, 05:56 PM
The above description is in the Wiki under General Technical Articles.

The Festiva is just a later Fiesta, so I suspect it's the same alternator or at least very similar.

The only terminals you need to deal with are the B+ and D+; I seem to remember that there is another terminal, which you don't need to do anything with.

05-08-2011, 09:20 PM
Thanks guys but the Festiva alternator is alot different!
Its tiny compared to the Fiesta alternator and I like the looks of it. Actually will give a little room in the engine compartment. Once I get a little time I will see if I can figure it out.