4 replies to this topic

[Sammy D]

Model:Clubby
Year:'76 (early before the changes)
Description of problem (please be as in depth as possible):
1. The red dash light; I understand the principle that when the alternator puts out the right amount of volts, the red dash light will go off. Question is, does it only have to get to that certain amount of current once?

Let me explain myself a little better. My alternator is dying I think, and the red light wont go out till you hit around 6000rpm or you have just been driving for a little while. Does the red light just need to see a certain amount of current once for it to go off, or if the current dips down again, will the light come back on? Or will it not come back on till I turn the engine off and on again?

2. The fan on the alternator; I had to take mine off becasue of my supercharger belt pulley spacing, I thought it was a bad idea but was desperate to get the car running. It's been like that for about 5 months now and only yesterday did the red light not go off for ages.

So the alternator is near enough fried, can I get one with an internal fan? Or what does the alternator look like from an MPi/SPi? As the only pulley I need on the alternator is the multigroove drivebelt.

Hmmn. Any help aprechiated...

Sam



Any non-standard parts that might be involved with the problem?

[Dan]

Firstly, to avoid confusion understand that voltage and current are two different things.

The warning lamp is not latching, if there is a higher voltage at one terminal of the lamp compared with the other terminal at any time it will glow. It will start glowing again if the alternator output voltage falls after starting. It would be a fairly useless warning lamp if it didn't.

Is your only problem that the warning lamp didn't turn off for a while? I suspect the main problem is that the fan belt is slipping. Alternators do require cooling, the fan is important. It will only do real damage when the alternator is at maximum load (when the current drawn by the equipment is high), meaning when everything is switched on. This is when lots of heat is generated in the alternator and it needs lots of air blown through it. It is always warm while running though and really needs cooling at all times. You may have damaged it as you suspet. All you need to do to get more clearance at the front for the fan is to space it differently on its mountings. If you really want a different one the MPi alternator is internally cooled but it mounts to the engine very differently.

[Ethel]

when you turn the ignition on 12v goes through the bulb, it lights, and into the windings of the alternator. When the alternator produces 12v that goes up the wire in the opposite direction to the 12v through the ignition switch and balances it so no current flows and the bulb goes out. If the voltage on either side of the bulb drops below the other by enough volts it will light again.

Check earth's, connections and the fan belt first.

[dklawson]

Dan and Ethel have described the function of the light and there's nothing I can add there. As Dan said, check the belt tension first before you spend any money.

As Dan said, the fan is important but there are alternatives with internal fans. If you don't mind branching out, do some Googling for Denso alternator conversions. Most Denso alternators have a fairly high output, use internal fans, and require minimal changes to fit to an A-series engine. Many Japanese cars are good donors for Denso alternators.

[Sammy D]

The belt is ok, it's only one belt that does all the waterpump/alternator/supercharger at the same time and tensions at the alternator.

Went out in it today and the light went off straight away, then came on further in the drive so it's got to be on it's way out.

I've heard of using an alternator from a Suzuki Swift which has an internal fan and already has the multigroove pulley. I'll have to have a scout out at the breakers.

Cheers for all your help!