71 Road Runner amp gauge conversion (rallye Dash)

[RobsRR]

I just pulled my rallye gauge instrument cluster and was going to convert my amp gauge. I was planning on using a sun pro volt gauge as I had done on a 68 barracuda. This swap is not so straight forward though. Does anyone know of a replacement volt gauge. I was going to try red line gauges but I know you have to send the cluster to them. I was also going to modify wiring after reading Mad Electric article. (bulkhead and alternator) Any thoughts?

[moparite]

Matching up a gauge is the hard part. Wonder if any of the gauge resto places have a solution/volt replacement?

http://www.madelectrical.com/electrical ... uges.shtml

[71bird]

Mopar Action did that conversion and found a gauge that looked really stock. I don't remember which brand it was, but if you can find that article it will say.

[mrsnicks]

Look at some of the older Stewart Warner gauges.

[RobsRR]

I will check it out. I want to use the factory face. Just looking to swap out the guts

[71_bronze_gtx]

I can't help out with where to find a drop-in voltmeter, but I can lend some insight into both the gauge issue and the wiring/terminals issue. As an electrical engineer with 37+ years experience I suppose I'm qualified.

First, the ammeter is best suited to show the status of battery chargING current - i.e. current flowing into or out of the battery. The voltmeter is best suited to show the charge level of the battery. Assuming the "health" of the battery is good (it can take and hold a charge), either one can be adequate. Ideally, both are used.

Normally, in steady-state operation, the alternator provides the juice needed for all the electrical loads, which does not go thru the ammeter, and it keeps the voltage at around 13.4 volts, which keeps a light charge current going thru the battery. Charging or discharging current is what is seen on the ammeter. If the alternator is not working, all electrical load current will be seen as discharge current on the ammeter.

The voltmeter shows system voltage at one point within the system. It's arguable whether that should at the battery connection or at some other point. In theory, it shouldn't matter UNLESS there are "bad" connections in the wiring.

With these old Chyslers, by far the weak link is the bulkhead disconnect and other blade type connectors under the hood. The become loose, dirty, and corroded over time.

When the high capacity alternator was factory installed, the bulkhead disconnect was "bypassed" for the wires going from battery B+ (red) and alternator B+ (black) to the ammeter. I did this on my car and it went a long way toward solving my low voltage issues. It's not even necessary to disconnect the original wiring. I just soldered some ring terminals onto #10 wire, popped a plastic plug out of the firewall, and hooked up the wires. A bit of a pain to get to the ammeter, but possible. Take out the front seat and lay there.

The blade connectors can be cleaned, and the female half partially reconditioned to tighten them up. It's also possible to solder the crimped connection, but that will generally require partially destroying the plastic insulator housing.

I've studied the 71 and 72 schematics and harnesses extensively and would be happy to try to help anyone trying to find a problem.

[RobsRR]

So I wasn't sure are you referring to the modification outlined by "mad electric". I sent the cluster to red line gauge works for the voltmeter. It seems like they have some good reviews. In the mean time I was going to make the other modifications outlined by Mad electric.

[71_bronze_gtx]

I agree with the modification of bypassing the bulkhead disconnect, and did the same thing that they describe.

I don't agree with their statement that the ammeter is the main means of power distribution, and they actually sort of refuted their own statement when they drew the circuit correctly, showing that the alternator is feeding all the loads without that current going thru the ammeter (with the car running). If the car is not running and a bunch of electrical loads are on, they do go thru the ammeter. Most people don't do this, but it's true that in certain very rare situations this could "overload" the ammeter.

I also don't really think it's necessary to used a crimped butt-splicer (in-line splice) when also soldering the splice. But, there may be certain situations where it's difficult to hold the two wires in position to make the solder joint and in those cases the crimp splicer helps out. Since the wires are stranded, I just merge the strands into each other end-to-end, then solder. If you use the crimp connector and actually crimp it, you can't get it apart. Usually you wouldn't want to but once in a while you do.

I think when you see those rare cases of the ammeter being melted, it was something very abnormal.

[73'BIRD]

Speaking of rallye I cant find a listing for the different interior packages or trim packages. Originally a ford guy and know the mustangs had standard, deluxe, and pony interiors. Just wondering what the RR had

[71_bronze_gtx]

Try exploring this site. This link goes to the library of Mopar literature of the day, but there's lots more to see here.

http://www.hamtramck-historical.com/library.shtml

Look at the dealership data book for 1973 Satellite for starters Click on 1970-1974, then on Plymouth logo in 1973 in the dealership data book row, then on Satellite.

Unfortunately, 1973 is one of the less populated years.

[73'BIRD]

Thanks again man