[s-cars] Alternator Musings

[Djdawson2 at aol.com]

In a message dated 7/14/2005 12:15:30 PM Mountain Standard Time,  
powellb at gmail.com writes:

Dave,

I went out, removed the battery cleaned the contacts and  ground strap
on both ends (everything was spotless already).

I then  hooked my voltmeter between the engine and the battery ground
and had a  voltage drop of 67 mV when everything was running. It should
be less than  50 mV. So, I removed the engine ground wire, cleaned the
contacts and wire  thoroughly and reconnected. Now, from where the
engine ground wire connects  to the body to the battery, there is about
3 mV drop; however, from points  around the engine (such as where the
coils are grounded to the head), there  is still a 60mV voltage drop.

It seems like the engine itself isn't  grounded very well; however, the
ground line for the engine is operating  well and its ground point is
perfect.




Sorry for the slow response... was out of town with no email.  I would  
suggest that you inspect/clean the positive cables and connections...  particularly 
at the starter.  I wouldn't get too caught up in trying to  cure a 67mV 
drop... not really significant considering we're talking DC  voltage.  If you can 
get readings that indicate a .1 volt drop when  measuring at the alternator vs. 
the battery, I'll think you'll be where you want  to be.  You've checked your 
grounds, now check the hot connections.
HTH,
Dave