Large and Little

[MoriniMan]

Getting my Mazda V6 to sit low enough (DOHC heads are tall!) has been tricky.



The alternator was one of the biggest issues. I took it off along with the sump which needs modifying for RWD anyway and was able to get the engine close to where I think it needs to go.

It was looking like I needed to make some major changes to the suspension tower for clearance, but the alternator the spec was 100 Amp. I remember the days of 25 Amp dynamos and 35 Amp alternators, so I decided to look for something smaller.



The little fella is a 50 Amp job from a Daihatsu Hijet that cost me £20 delivered off ebay. It just over half the diameter of the original and should fit just fine. In an ideal world it would have had a Poly-V pulley to match the engine, but they're not hard to make.

These small alternators are often sold for 'race' or 'kitcar' use at £100+ but quite a few cars use them as do some industrial engines (Kubota for example). The latter are sometimes one wire devices, which means you should use a heavy duty relay to isolate them or they will run the battery flat if the vehicle isn't used for long periods.

[Alpha]

Smart move, the lack of 'creature comforts' in the Sammio makes the smaller alternator perfectly adequate!

Or are you planning on installing a large sound system, airco, electric mirrors and seats, coupled with some snazzy 'glow lights' underneath the sills? Then I might reconsider..:-)

Baz from Brussels

[oxford1360]

We once did a 24-hour race in a 2CV with a 30 amp alternator without any problems. We managed to light the track and the roundels, and keep the battery charged all night with one or two amps to spare. It's surprising how little you need if you don't have a heater motors, heated seats and in-car entertainment. The steering and brakes will provide more than enough ICE for me.

[WorldClassAccident]

This could be good news for me then. This original alternator is not kicking out much power even though it is a big old lump.

[Jerome]

Hello,

Due to some conversions I have no space enough for my alternator in Vitesse MK1.
This is still a DC alternator,does anyone know how to replace for a smaller AC
alternator?

Anyone?

[MoriniMan]

Originally Posted by Jerome

Due to some conversions I have no space enough for my alternator in Vitesse MK1.
This is still a DC alternator,does anyone know how to replace for a smaller AC
alternator?

Alternators produce alternating current - AC, hence their name.

These days they usually have a built in rectifier and usually also a regulator to output direct current - DC.

An older generator or dynamo will nearly always have an external regulator and this will usually be an electromechanical device, rather than electronic. Modern electronic regulators are available to improve charging and some are fitted into the old style regulator boxes for originality. You can even get alternators built into dynamo cases.

Fitting a different alternator is mostly a case of making up some suitable brackets. Wiring it will depend on the alternator. There are alternators that have just one high current wire to the battery (usually from industrial engines), but most have at least one additional control or signal wire.

Old Lucas alternators had a combined control/signal line. A feed from the ignition switch goes via a charge indicator light to the alternator and if the bulb fails the alternator won't charge reliably, so you have to check for an illuminated indicator light when the ignition is switched on, but before the engine is started. Other alternators have separate ignition and charge indicator feeds and some modern alternators have an additional control line to change the output voltage.

[Jerome]

Thanks

Now I know what to look for