[DeTomaso] 1972 gumball detomaso pantera

[JDeRyke at aol.com]

In a message dated 10/6/09 11:24:05 AM, LEVITT1946 at aol.com writes:

> Now that my engine is out of the car it would be good to update 
> the alternator . If I boost the alternator power to 150 amps i have been told that 
> it will burn out the ammeter and i should  install a voltmeter instead .Are 
> there other precautions to take when upgrading the alternator ?
> 
Three things: first, installing a shunt on the stock ammeter allows some or 
most of the charging current to bypass the meter. This saves your wiring 
from melting and CATCHING ON FIRE! A shunt is simply a short, large wire or a 
flat copper/brass plate bolted directly across the ammeter terminals. In 
proportion to the surface area of the shunt vs. the charge wire, the meter 
reading and the charge going thru it is reduced. Many Pantera owners do this 
even with a stock alternator to reduce amp-gauge flickering, figuring the meter 
reading is inaccurate anyway.
Second, by nearly tripling the alternator output from stock, you'll need 
MUCH larger charge wires all the way to the battery! In fact, unless you're 
using the car's alternator to drive an electric welder or a ham broadcasting 
station, I can't think of a circumstance where you'll need   a full 150 amps 
at 12V. 
Third, you may need a dual-sheave pulley to actually turn the big alt under 
full charge; one source says that every 25 amps of alt power pulls 1 
horsepower from the crankshaft; the stock drive pulley and belt (if tight) was 
good for around 75 amps, NOT continuous. There may be mechanical fitting prob
lems to the stock bracket since this size alt may not physically fit in the 
same area. It will likely weigh more than a stocker (11 lbs) too.
More alt power over the stock 61 amps is fine, but maybe 150 amps is 
pushing the idea too far?   I now use a modern 75-amp internally-regulated 
alternator, with the stock wire sizes. Contemporary Ford Police cruisers often used 
a 105-amp alternator (nearly the same physical size as a stocker) for their 
radios, flashing lights etc. Good luck- J Deryke