Failed alternator

[SteveB]

After running for the 40 min the Enthusiasts Club had set up at Le Mans Classic with headlights fans pumps etc on, the alternator gave up the fight and died. I found out the next day as we drove back to ferry, the battery just made it to the port it all came to a stop on the dockside.

Here is the question. The unit on the car is the 100 amp Ford Mustang one wire ( G2? ) It is mounted on the rhs and is in confined space; the pulley is backed by a chrome disc. There are limited fan cooling blades but the alternator has little by way of cooling vents.

Has the heat build up and lack of cooling done for the alternator?

I have looked at some 100a UK one wire alternators (TVR & Landrover) they all have fan equipped drive pulleys and have plenty of vents to allow cooling air to be drawn through the body of the alternator.

Would this type be more suited to the task?

We made it home ( on a truck ) After a good long charge the battery has recovered; on start up the alternator was not delivering high enough voltage to produce a charge to the battery. however it did dim the ignition warning light, in the bright French sun it had appeared to go out.

Any help on this would be appreciated before I either buy a replacement or modify to fit the more vented type.

Steve

[Tony Hunt]

Hi Steve,
Sorry to hear your alternator was a casualty of the LMC track laps.
The replacement to go for is by Racemettle - and you get a Club discount. They advertised in Fortyfication a while back.
Talk to Frank Catt about which one to buy.

[Chris Hale]

Hi Steve,

I had exactly the same problem with my alternator at LMC 2010; my alternator was still outputting some current as I managed to make it home.

If I measured the voltage at my battery with the engine running it was around 13.2v and after the long run back from Le Mans to the port it finally got up to 13.8v, but this was only due to me not using any aircon and keeping the engine cooling fans off while I could.

My alternator is also 100amp and of the one wire type, on inspection of my alternators internals I found that one of the three connectors that attaches to the three windings had broken loose, so re terminated and soldered this and all works as it should, my battery voltage is now 14.8v when the engine is running.

So I would look at your alternator before you decide to buy a new one as you may have a simple fix like me, if you look on line there is allot of helpful videos on YouTube to help you identify faults.

Hope this helped all the best,

Chris.

[Al Snow]

I have had a couple of alternator problems which are now sorted and have done about a 1000 miles on a Nippon denso one off I think a micra. I am not running aircon but am doing electric water pump and I think the thing is rated at 85 amps. I note that some of the mustang race places seem to be suppling these units. It can be a pain to get a pulley version but they are about.

And as for Land/rangerover ones... I think Mick at Southern GT does them or at least some are fitted to his cars and I undestand they are good and and if you ever need to replace one it should never be a problem.

Anyway take care and I hope this is of some help... cheers alan

[SteveB]

Thanks for the feedback

After trying a Landrover unit ther was just no room for it without some reworking of the engine bay area so I took Chris's advice and took the old unit apart. All the wires were in place, however the nut inside that secures the main 'battery' terminal had been hot and was not tight.
After finding the springs that flew out from behind the contact brushes I cleaned up the corrosion and tightened the nut then reassembled the alternator. You can put a split pin inserted from outside the cover to retain the brushes while the cover is refitted.

On startup the voltage was correct everything returned to normal.
I think the alternator was sensing the battery voltage through the higher resistance due to the poor contact, resulting in reduced output that could not charge the battery. The heat and vibration of the LMC track laps was the last straw.

I think the problem may have been with me for some time but disguised by my keeping the battery topped up with a conditioning charger. I think the voltage drop on the system was affecting EFI system as the engine now runs a great deal sweeter

I have noted that the single vee belt is now slipping and needs to be pretty tight. Has any one converted to the flat multi rib belts?

Steve

[Jack Houpe]

I recomend the GM 1 wire, I bought one off ebay thats 200 amp, used for car stereo people and its been great.

[Martin]

Steve,

Mick Sollis supplied me a Land Rover unit. Internal Fans, high Amperage. Not sure what model you have that didn't fit but the one I have fits in the space no problem. I haven't bracketed it up yet, but theres definitely room for it.

Martin