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Generator polarization/alternator

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truimpas Robert Petrauskas
Apollo, pennsylvania, USA   USA
Last week I changed from positive to negative ground so I could use electronic ignition. I did all the usual things for this & all is OK, except every time I shut the car down & restart it I need to repolarize it to get it to charge. What might I be missing. Also what would be an inexpensive alternator to use. I suppose it wouldn't matter if it had an external regulator or not. Just wondering about that wide belt.

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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
My guess is that you have a fault in the generator or control box, which is masked by your repolarizing. Just coincidence that it showed up during the conversion. Here's a list of tests to try:
https://drive.google.com/open?id=0B2H2NJt34OffNTc3ODkwYzAtYjRlYS00NDNmLWI0YTYtNjY5ZjQxZTA2NGFm

The GM/Delco 10Si or 12Si would probably be the cheapest, but involves some modifications. As you say, sourcing a pulley for the original wide belt is one problem.

I went a different route on my TR3, due to the lack of room, and used a rebuilt alternator from an 89 Suzuki Swift. RockAuto had a closeout and was selling them for $40 (but closer to $100 now). I'm real happy with the way it turned out


But, I did have to machine the generator pulley to fit the alternator.





I also machined my own adapters, but I think you could cut down the original front pedestal and use a length of pipe for the rear one.




Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

truimpas Robert Petrauskas
Apollo, pennsylvania, USA   USA
Thanks for the info. The wide pulley on the GM wouldn't be a problem. It's a popular conversion on tractors & I did my International that way. I also did a 31 & 51 that way. I like the Suzuki for compactness, I guess I would need some specs on the pulley to have a machine shop to do it. Is that Suzuki a 1 wire deal or does it need a regulator?

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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
In reply to # 1489531 by truimpas Thanks for the info. The wide pulley on the GM wouldn't be a problem. It's a popular conversion on tractors & I did my International that way. I also did a 31 & 51 that way. I like the Suzuki for compactness, I guess I would need some specs on the pulley to have a machine shop to do it. Is that Suzuki a 1 wire deal or does it need a regulator?
Sorry, I didn't do a drawing. I've actually done it twice now, and the alternators were slightly different, resulting in slightly different mods to the pulley. On the first one, I just added a small spacer behind the pulley and thinned the area where the nut goes. The shaft was the same diameter in both cases, but shorter. On the second alternator, the shaft was even shorter than the first, so I machined the back of the pulley to fit down inside the end cover (removing the need for the spacer).

The regulator is internal, but there are some other wires required. One is the output to the dash lamp, another is the 'sense' voltage from the battery, last is power from the ignition switch. I gutted an old control box and added internal jumpers so I could use it as a tie point. (The 'sense' wire might not actually be required for the alternator I got, but I ran it anyway.) This photo shows all but one wire (the 'sense' wire branches out and goes to the starter solenoid).




Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

truimpas Robert Petrauskas
Apollo, pennsylvania, USA   USA
From what I understand your 2nd one required less machining. I could just grind the back of the pulley to make it "thinner" to accommodate a shorter shaft. So what info do I need to buy this one? (Yr,make model eng size)

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
The second pulley is shown above, and it was a lot more work. Part of that was because the original bore was not square to the edges (you can see where I squared it up while holding it on a mandrel through the bore). Not obvious in the photo, but the groove in the back goes below the surface of the pulley, so the pulley actually sticks back a bit around the outermost part of the alternator. But the front had to be thinned as well. That shaft is really short!

Application was an 89 Suzuki Swift, it only came with a 1.3L L4 engine. However, it appears that several different alternators were used, and I don't know how different they are. The one I got the second time said "Remy 14464" on the box; I don't have the information from the first one handy.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

truimpas Robert Petrauskas
Apollo, pennsylvania, USA   USA
OK thanks for your help. I'll see what I can come up with.

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volleyball Ray C
Albany, NY, USA   USA
I used a 70's GM 10 that was 37 amp. It is the second lowest power one you can get. I used the generator pulley and only had to grind off a little bit of the fins. Went to NAPA and asked for a longer belt. I used an adjustment rod from my junk drawer.
I made some terminal adapters so that I would not hack the original wiring. Used a matchbook, and shorted a pair of contacts in regulator and it was all done. Because the alt is 37 amp I use the ammeter and original wiring under the dash.

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
In reply to # 1489706 by volleyball Because the alt is 37 amp I use the ammeter and original wiring under the dash.
Good point, I forgot to mention that. My original ammeter didn't like hitting the peg after every start and began to stick, so I added a shunt across the back. The shunt takes roughly half of the current, so the ammeter reading is about 1/2 of what it would be otherwise. So +50 amps of charge shows as +25 on the ammeter. Other than that, all the wiring under the dash is original.

I originally did this on my previous TR3A back in the 80s, with a 60 amp Ford alternator. Never had any trouble with the wiring itself, even with my 120 watt headlights, electric radiator fan and high power stereo (takes a lot to be heard at 75mph!)





Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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volleyball Ray C
Albany, NY, USA   USA
The 10 gauge wiring isn't designed to take 60 amps. Could warm up the wiring bundle enough to cause some melted wire insulation. A shunt needs to have equal resistance for the gauge to read half. Although you only really care about a charge or discharge indicator. 37 amps is plenty for Triumph electrical needs plus led driving lights

truimpas Robert Petrauskas
Apollo, pennsylvania, USA   USA
If I'm looking at your picture correctly, you're using a piece of wire 2-3" long as a shunt?

volleyball Ray C
Albany, NY, USA   USA
The wire is looped so it is several inches long. But probably still not long enough to give resistance equal to the gauge.

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Actually, it is very close to the same resistance as the gauge. 16 AWG is given as 4 ohms/1000 ft or 4 milliohms/foot. I measured the gauge at 1.2 milliohms, then cut a piece of 16 AWG 3.6" long.

I don't know if the later "flat glass" ammeter would be the same or not. A friend of mine measured his early TR6 ammeter at 2.7 milliohms.

Another way to go (and what I did the first time around) is to simply hook it up, turn on the headlights and note the reading. Then add a length of wire and try it again. Adjust the length until the reading is half (or whatever ratio you want) of the original reading. Not very precise, but as Ray pointed out, precision really isn't important here.

At the time I did my first alternator conversion, about 1975, I was working 2nd shift and the TR was my only transportation. Only a few miles from home to work, so only a short time to recharge the battery after each start. I got really tired of having to mess with battery chargers and, more than once, having to push-start the car by myself at 1 AM in the snow. (That was in north-central Indiana; gets a lot colder there than it does here.) Oh yeah, high power LEDs hadn't been invented yet, so I was running high power halogen headlights instead. In that case, the previous owner had already fitted an aftermarket 60 amp ammeter, so I used that instead of a stock meter with a shunt. But it was still original wiring to/from the ammeter, and the wiring never gave me any trouble.

As a side note, I owned a Chevy for awhile that I ordered with "heavy duty" electrical, including an 85 amp alternator. It's power wiring was even thinner than the TR3s!



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

truimpas Robert Petrauskas
Apollo, pennsylvania, USA   USA
So here's the update; I purchased an 80 Chevette 3 wire alternator, proceeded to swap pulleys only to find the GM alt. shaft to be much larger than the TR's. So I used the GM alt. with the narrow pulley & used a non-automotive belt (1/2 wide x 5/16 tall). It falls in the narrow pulley enough to be OK & rides high enough on the wide pulleys to be OK. It charges fine, I've yet to get the amps meter to work. It has plenty of volts like around 14. I'm assuming a Chevette would be 37 or 42 amps.

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Looks like 42 without A/C, 63 with.
https://www.rockauto.com/en/catalog/chevrolet,1980,chevette,1.6l+98cid+l4,1040061,electrical,alternator+/+generator,2412



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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