View single post by Mark Rosenbaum
 Posted: 05-17-2005 03:27 pm
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Mark Rosenbaum



Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
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 If the alternator isn't producing electricity, then you are indeed operating only on the battery.  This can be verified by clipping a charger to the battery.  If the battery accepts a fairly heavy charge for several hours, then there's something wrong in the charging system.  OTOH, if the battery is fully charged when you start, then most likely you have a problem in the warning light wiring and another problem in the voltmeter or its wiring.  (Simultaneous multiple failures are quite rare but not entirely unheard of.)

Most likely your problem is (1) a dead alternator, (2) a wiring problem in the engine bay, or (3) a shorted cell in the battery.  If the car cranks and starts normally, then unclean battery connections can pretty much be ruled out. 

(1) The alternator is best checked by dismounting it and taking it to one of those parts stores that does free tests.  As it happens, JH alternators are still commercially available, so if yours is bad, there's a very good chance the store will either have a replacement in stock or can get it quickly.  Alternately, you may wish to have yours rebuilt, or switch over to a single-wire alternator.

(2) Make a visual check of the wiring.  Check the ground wire between alternator and engine block for connection and condition.  Make sure the connectors that plug into the alternator are seated, and that there are no wires broken off just inside the connector, then unsnap the plastic cover over the junction on the heavy positive battery cable, and make sure the thick brown wires that goes to the blade connectors there are all firmly seated and that there is no corroson present.

(3) Using a hydrometer, check the specific gravity of the electrolyte in each cell.  The reading for every cell should be about the same; gross differences may indicate a fault.  If the battery is not fully charged, then charge it for a couple of hours and recheck the specific gravity.  If (a) the specific gravity in each cell has not risen noticeably, or (b) there are still gross differences between cells, the battery has failed.

When a JH is being particularly stubborn, a brisk talking-to, or the threat of using French- or Italian-made parts, will often shame the beast into submission.  But if you find that you must use the shotgun, a decent appreciation for the proprieties requires that you use only ammunition manufactured in the UK.  A single shot applied directly to the base of the distributor will give a quick, clean kill.  :^}