I just did the conversion on my GT6+ engine, and my part was a #7127-somethin as
well. The application was a 1978 Chevy Truck with 350 engine. I believe the
plug was at 3:00. Wow, what a difference!
Isaac Crow
'74 Spit6+ with up to 55 amps of raw 'merican current...
Winder, GA
DANMAS@aol.com wrote:
> In a message dated 98-10-06 13:34:26 EDT, Bud_Rolofson@nps.gov writes:
>
> > Put a voltmeter on the plus lead of the coil, and to see what the voltage
> > read
> > with all the above electrical devices turned on. According to Dan If it's
> > the
> > alternator that's the problem, you should see a fairly large voltage drop.
> > I
> > didn't see a large drop...the voltmeter still read 12 volts.
>
> Bud,
>
> It is normal for the smaller, underpowered, alternator on a TR6 to experience
> a small voltage drop with all loads on. Try a voltage reading with all loads
> off (rpm above 1500). If the voltage stays around 14 volts, you are OK. There
> is quite a bit of variation in alternator output voltage from one unit to
> another, but theoretically, they all should produce 14.6 volts under light
> load.
>
> When the alternator is loaded so high as to drop the voltage to the battery
> level, what you are doing then is drawing power from the battery.
> Theoretically, a good battery should produce 12. 6 volts. If for example, it
> takes 30 amps to bring the alternator voltage down the battery voltage, and
> you have applied a 35 amp load, the extra 5 amps will come from the battery.
>
> Check the voltage again with no loads, and if it is around 14 volts or more,
> then no reason to worry. If it is less than 13 volts, then you may want to
> consider getting the alternator repaired or replaced. In between, it's a
> judgement call.
>
> That is one of the advantages of the larger GM unit. Even though the Lucas has
> sufficieant capacity, when fully loaded the voltage goes down, causing a
> corresponding reduction in light output, etc. The 55 amp GM will provide the
> typical TR6 load and still maintain voltage.
>
> I bought three GM units in the last year or so, from two different stores, and
> they all three had the 7127 model number, so I assumed that must be a
> universal number. Evidently not. Anyway, the model you want is called a
> "Delcotron SI", and was used on GM cars from the eary '70s till the mid '80s.
> They are almost universally used in Street Rod applications, so if you can
> find a store that caters to that crowd, you should have no problem getting the
> right one.
>
> I can get them locally for about $24 -$30 dollars, plus a $15 core charge, so
> if you can't get what you want in your area, I can get you one and ship it to
> you. They are fairly light, so shipping costs should be small. They can be
> sent UPS or USPS.
>
> Hope this helps.
>
> Dan Masters,
> Alcoa, TN
>
> '71 TR6---------3000mile/year driver, fully restored
> '71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
> http://www.sky.net/~boballen/mg/Masters/index.html
> '74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
> '68 MGBGT---organ donor for the '74
--
**Work is the curse of the drinking class. **
--Oscar Wilde
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