Quick alternator question

[bigjones]

Battery reads about 12.5 volts with engine off.
About 14 volts with engine running at 1000 rpm.

Is the alternator OK?

Cheers,
1500 Midget
Adrian

 

[Trevor Jessie]

Yup

 

[bigjones]

Cheers Trev.

 

[dklawson]

Hey Adrian! Good to see you on the board again! Hope all is well over your way.

 

[bigjones]

Doug,

Thanks for the welcome back.

I've been concentrating on my other hobbies - beer making and woodworking.

The MG is running great - however the alternator is making what I think is a (loud) bad bearing noise. My backup alternator has a bad diode and I managed to break one of the wires de-soldering the diode (to test with a multimeter).

I could get a reman from Advance Auto for about $66 but the last one I got from there was DOA - doesn't say much for the QC, does it.

Then again I could get new diode and bearings and try to fix both of them.

Or get a new(?) one from RockAuto for about $73 shipped but I'm thinking the warranty (they are made by Uro) may be a problem.

Moss and VB, of course, have new ones but they are well over $100.

Still pondering it.

Apart from that - everything is cool - hope you are doing well yourself.

Cheers!

 

[Trevor Jessie]

Maybe switch to something like this:

https://www.mgccars.com/100_amp_alternator_upgrade.htm

These alternators were used in early Saturns.

Plenty of amps in case you want to install a huge stereo to inflict your taste in music upon others. :wink:

 

[bigjones]

Trevor,
Thanks for the link. Let me ponder.
Cheers!

 

[dklawson]

Adrian, from memory isn't your Midget a 1500? If so, another alternative would be one of the common Delco 10Si or 12Si alternators. Check some of the Spitfire web sites for information on the conversion. Like this one:
https://www.cwnicholls.com/spitfire05.html

These are not expensive alternators from places like Advance (probably less than $50). I happen to have one on the GT6 and I was very pleased with the condition of the rebuilt unit I bought. I believe it came with a lifetime warranty.

EDIT: Also see Paul Tegler's page discussing the Delco swap on the 1500 engine.
https://www.teglerizer.com/alternator/index.html

 

[JPSmit]

i managed to do the delco swap with no cutting at all. The only thing I changed was the plug to the delco wore pattern

 

[CraigZ]

Maybe switch to something like this:

https://www.mgccars.com/100_amp_alternator_upgrade.htm

These alternators were used in early Saturns.

Plenty of amps in case you want to install a huge stereo to inflict your taste in music upon others. :wink:

Has anybody actually puchased and installed one of these conversions? I have the classic very dim/flickering red light at idle...new battery, clean connections but the classic flicker :frown:

 

[Trevor Jessie]

You have the dim flicker with a lucas alternator or a generator?

 

[CraigZ]

Alternator...'73 Midget. The instant the rpm's get above idle the light goes out and stays out. I have another alternator that needs to be rebuilt (some moron [me] crossed the leads when jump starting the car and let the smoke of its diodes...)...that alternator was strong until I cooked it...

 

[jvandyke]

I thought the light was supposed to flicker at low rpms, telling you that you are at the threshold of not making enough juice. Mine red light does that at extreme low idle (when engine still cold). It goes out when things are warmed up and idle is back near 1,000.

 

[JPSmit]

Maybe switch to something like this:

https://www.mgccars.com/100_amp_alternator_upgrade.htm

These alternators were used in early Saturns.

Plenty of amps in case you want to install a huge stereo to inflict your taste in music upon others. :wink:

Has anybody actually puchased and installed one of these conversions? I have the classic very dim/flickering red light at idle...new battery, clean connections but the classic flicker :frown:

I have the GM Delco conversion on my 1500. Works great!!

 

[JPSmit]

Though I didn't have a flickering problem before till I er fried the alternator. Might be worth taking the alternator off and taking it to an auto electric place and see what they say. Certainly you can test in situ whether it is charging

 

[dklawson]

A volt meter across the battery terminals with and without the engine running will give you a general indication of the alternator condition. A good battery that is fully charged will read about 12.5V at rest. When you start the engine, there should be a voltage rise (nominally 1.5V) across the battery terminals. Hopefully you'll see something around 14V across the battery when the alternator is running. However, that 1.5V is nominal and varies from alternator to alternator.

Regarding the flickering light, that was much more common with generators than alternators. In general once an alternator "pulls in" and starts generating, the RPM have to get very low before it stops charging and the red light comes on. There are always exceptions though.

CraigZ asked about the Saturn conversion. (Hello by the way, nice to know someone local to me is on the board). I have a few acquaintances who have fit Saturn alternators to A-series engines but they have done the conversion themselves and not bought that kit. Delco is a possibility as are many Nippon-Denso alternators. Almost anything can be made to work if there is room and the pulley to mounting ear offset is close to right. I have a Delco on my GT6 and a Motorola (Bosch clone) on my Mini.

 

[jlaird]

light should flicker at low RPM above 1000 you should not have it on.