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Sat Aug 22, 2009 12:45 pm

i recently hooked up a 12 volt alternator to a 68 sand rail. i disconected the 6 to 12 vonverter. it was a 6 volt. i bypassed the converter. i dont know if this is linked, but im having a charging problem, as well as a starting problem. it started about 10 or 20 times, but now all it will do is turn and almost start. its also burning a lot of oil, and two of the spark plugs look oily.

Sat Aug 22, 2009 3:24 pm

As for converting from 6 to 12 volts everything on sand rail has to be upgraded to 12 volts.... Battery, lights, ign coil. As for charging problems, it depend on if your alternator is a 4 wire (Motorola AL78 ) or a 2 wire alternator) Bosch AL82. The AL 82 is internal regulate and does not require external regulator, but does require having idiot lamp hooked up, the AL78 is externally regulate and requires a external regulator, no the regulator for old generator system will not work....

Need more details on what alternator type you have to better understand your problem with electrical system...

Check out " Alternator Basics" downloadable document near bottom of this link...

http://www.mydune-buggy.com/techpage.html

Oily spark plugs usually are indication that piston rings are begging to be replaced....

Dale

Thu Jan 07, 2010 8:54 pm

I recently built an engine from spare parts. The alternator is a Motorola AL78. My battery isn't staying charged. I'm not sure if the regulator is working. How do I know if the regulator I have is for 6v or 12v? Is there a way I can test the alternator and regulator without a voltmeter?

Thu Jan 07, 2010 9:16 pm

6 volt regulators were usually mounted directly on generator...

Depending on year of car it may have a AL87 as you say but it may be you have a regulator (and bastardized wiring) that was designed for a generator. If so its not going to work.......

Generally a external 12 regulator for a AL87 alternator has one single 4 prong socket/plug connection....

To check if alternator is working basic test is ALT light should go out when engine is at any RPM above idle......

Best test is voltmeter.... Even one of the really cheap volt meter (less than $10 -digital) will work. A fully charged battery at rest (engine not running) should have a full charge voltage of about 12.75 to 13.25 volts, when alternator is charging voltage should rise to 13,85 to 14 .25 volts (all measurements directly across battery) ...

Dale

Thu Jan 07, 2010 9:16 pm

Here's an interesting link I found tonight while fixing my long-lived alternator problem. It talks about the wiring of the idiot light, and how it is essential to alternator operation.

http://www.vw-resource.com/alternator_wiring.html#alt

Might help you some with your charging system problem.[/url]

Thu Jan 07, 2010 10:36 pm

i have a mechanical regulator will that work with the alternator? if the alternator passes the test is there a way to test the regulator? and if my regulator will only work with generators does it matter if they are 6v or 12v generators when it comes to picking a mechanical regulator?

Fri Jan 08, 2010 8:47 am

Let me start over.....

6 volt regulators only work with 6 volt generators...

12 volt regulators for generators only work for 12 volt generators. NOT alternators...

12 volt external regulators for alternators (AL78) only work with AL78 type alternators. NOT generators or internally regulated alternators (AL82x)...

12 volt alternators (AL82x) internal regulated, do not have external regulator....

Dale

Fri Jan 08, 2010 9:27 am

how do i know if the generator regulator i have is a 6v or 12v

Fri Jan 08, 2010 9:50 am

If it is a bosch regulator, it will be stamped into the side of the mounting bracket.
If it is an aftermarket, and is not stamped, if it is designed to mount on a flat surface, it is probably a 12V. If it is designed to mount on a curved surface, it is probably for a 6V.

Fri Jan 08, 2010 9:52 am

Why are you asking about a regulator for generator, I though you said car has ALTERNATOR.... Typical external regulator for AL78 Alternator has a 4 prong plug in square configuration.... If you have anything else, its probable not right....

http://www.mydune-buggy.com/home/dl_files/AlternatorBasics.pdf

Dale

Fri Jan 08, 2010 9:41 pm

if your car has the three prong connection for the alternator, then you can use either the internal or external regulated alternator. if the alternator itself has the three prong (externally regulated alternator), that plug it up as intended, but if the alternator has only the one prong (internally regulated), that all you have to do is to hook up the middle connection on the plug to the alternator (i think it corresponds to the red wire). that wire leads to the idiot light.

If your car was origionally set up for a generator, then thats a whole nother situation, and i'm not too sure about that. i would think, that an internally regulated alternator would be the best, and that you just need to hook up the power, and the idiot light, which i believe is the red wire, but not sure about that. i just studied my bently manual's wiring schematic and figured it out, lol.

also, if your motor origionally had a generator, then you would have to change out the generator stand for an alternator stand. a generator stand can only use a generator. an alternator stand can use either an alternator or generator. the "fat part" of the alternator will interfer with the generator stand, and an alternator stand accounts for the "fat part".

Sat Jan 09, 2010 12:37 am

i have both a spare generator and spare alternator but i only have a mechanical regulator so im deciding if theres a way i can use the alternator without an electronic regulator