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Discussion Starter · #3 ·
If everything is stock then why add the complications of one wire alternators. They can be rather pissy on the street where low RPM gearing and typical engine operation is the norm.

For an as built factory stock car this is just an unneeded complication.

Bogie
because I cannot get above 11.5 volts, I've replaced starter, regulator, battery...nothing gets it above 11.5, auto zone checks alternator, checks out and besides, they don't have the replacement.
 

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You say the aftermarket gauge reads 11.5, what is the voltage at the alternator output stud and the battery positive? A bad connection or cable would show up as a high reading at the alternator and a low one at the battery. Any voltage difference between them is loss and it producing heat. It sounds to me that the alternator has a high resistance connection to the battery.
 

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Discussion Starter · #12 ·
I replaced with one wire, still right at 12, 11.5 if anything is turn on.
I noticed something; if I slightly move the ignition one way or other, volts change and range from 11.5 ro 12.2.
I am thinking I should replace the switch and or cylinder?
 

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Or the battery, take it somewhere that can load test it to see where the starting voltage reads then they pull a prescribed number of amps while observing how long it takes to pull the voltage down then how long and how far it recovers. If there are shorting plates which is an age problem where material that stuffs off from normal use bridges the plates the voltage potential at test will look pretty normal but a load pulls it down and it will stay down.

In the car the alternator voltage will always look low as to it the battery is now a load that sinks charge.

So before you spend a small fortune both in dollars and time get the battery professionally load tested.

Bogie
 

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Where are you measuring the voltage. You need to use a multimeter for testing. Measure at alternator, ignition switch, and battery. All voltages need to agree. You have loss somewhere if they don't.
 

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I replaced with one wire, still right at 12, 11.5 if anything is turn on.
I noticed something; if I slightly move the ignition one way or other, volts change and range from 11.5 ro 12.2.
It's flat out not charging....alternator is not working or wired incorrectly.

A good battery should test near 12.6V.....anything less while running says alternator is not functioning. If alternator were charging, it would show at least 12.8-13 v

Did you bypass the stock original seperate Voltage Regulator with a couple of jumper wires in the connector at the regulator??
This has to be done on the pre-71 GM's when converting to a newer alternator that has an internal voltage regulator.

how to rewire alternator wiring harness for internally regulated GM conversion chevelle - YouTube
 

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Bypass the external regulator and use a 10si or 12si alternator with single groove pulley from a 70's GM vehicle. Mad electrical web site has a lot of good info on finding a 94 amp 12si, which should cover all your needs. Catalog

Also upgrade the charge wire to an 8 gauge wire with fusible link, and run it directly between the BAT terminal and the battery. The simplest source is a junkyard full of 80's GM vehicles, since most had an equivalent charge wire and the fusible link will already be there.
 
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