Hello. I went to the parts store to get a new alternator for my 1969 valiant, all original with external regulator. The original is a round Back unit with one field wire and the charging post at the back as it should be (correct?) the parts store gave me a newer style with the square part at the bottom with the internal regulator. Is that ok to put on there? It does appear to have a piece screwed on over one of the terminals on the back that makes it too wide to put the wire terminal over. Is this a way to ensure you just use the one wire terminal i the right spot and this alternator is set up to use with the old system? Or is this just wrong? Any help appreciated! Tanks
Internal Reg.alternator on 69 valiant?
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67Dart273
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This is getting really common The squarebacks, generally are better alternators, if you are not concerned about "restore correct looks." CAVEAT!!!!! Make CERTAIN the modified brush is actually grounded, or it will not charge, and make certain the accessible brush is NOT grounded. That is, it should show a small resistance as opposed to a short, maybe 2-3 ohms or a bit more
The difference electrically, is that the pre-70 regulators controlled power going TO the field, which was grounded
the 70/ later cars had 12V direct to one field, and the VR controlled "the amount of ground" so to speak to control output. Isolated field alternators did not actually start with the squarebacks. The first isolated field alternators in 70 were roundback units.
The difference electrically, is that the pre-70 regulators controlled power going TO the field, which was grounded
the 70/ later cars had 12V direct to one field, and the VR controlled "the amount of ground" so to speak to control output. Isolated field alternators did not actually start with the squarebacks. The first isolated field alternators in 70 were roundback units.
Interesting. Perhaps I’ll wait to get the original fixed up to avoid issues like that. I want to keep things original, it’s a pretty nice survivor car. I just wish I got a direct replacement from the parts store, maybe I’ll ask them to see if it’s possible to get an exact replacement. Thanks!
You will have a hard time finding a parts store that can pick and chose.
The goal for the automotive aftermarket is minimize inventory and increase profit. Even brake parts are too often 'close enough'.OK. I'll get off the soap box and give you some links so you can do some checks.
One check is figure out what is wrong with the alternator that was on the car.
Two figure out if its 'safe' to run the replacement.
This is easy. Do a current draw test. If the rotor is drawing a lot more current than the shop manual specifies, there's a good chance the regulator will fail sooner. More current through those small wires is more heat.
A revised squareback was designed from the begining with rotrs that draw more current.
However a roundback or regular squareback that has been 'rebuilt' could have a rotor that also draws more than stock. So its worth checking.
Basic operation and photo ID of the parts.
Identifying Chrysler Alternators (1960-1976)
Roundback and Squareback refer to the style of housing. Roundback through model year 1969. Roundback for model years 1970-71 usually has a slightly different rear housing Squareback Revised Squareback Is most easily differentiated by the thin middle between the housings. Overall these...
www.forabodiesonly.com
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These tests require a multimeter that can measure several amps of current. Such meters often have a fuse in them to protect the circuit.
The service manual also describes this test, but at that time, cheap handheld multimeters did not exist.
Field draw test with alternator on the car.
First make sure there isn't a short to ground.
Then loosen the alternator so you can turn the pulley by hand.
Using a meter that can measure a few amps, set it to the 10 amps scale and alligator clip it like this.
Be super careful not to let either clip touch ground.
Check the battery voltage during the test if you have a second meter. If not, measure before or after.
When turning the pulley by hand the current draw should be between 2.3 and 2.7 amps.
That's from a 12/61 tech pamphlet. Alternator and Cranking Motor (Session 169) from the Master Technician's Service Conference
Field draw test with alternator on the bench.
You can do it on the bench as well.
Ignore the mess. Grounded field alternator.
1. Connect the alternator housing to ground. On the car that's already done by being mounted.
2. Set the multimeter. For this one it means plugging one of the leads into the 15 amp position and turning the dial.
3. Connect one lead of the the multimeter to the power and the other the alternator's field terminal.
Try to turn the pulley while taking the reading. Disconnect. Done.
A 'squareback' will draw a bit more. I've measured 3 amps on an original and 5.8 amps on a remanufactured one.
3 amps I wouldn't worry about. 6 amps I think is pushing the limits.
The service manual also describes this test, but at that time, cheap handheld multimeters did not exist.
Field draw test with alternator on the car.
First make sure there isn't a short to ground.
Then loosen the alternator so you can turn the pulley by hand.
Using a meter that can measure a few amps, set it to the 10 amps scale and alligator clip it like this.
Be super careful not to let either clip touch ground.
Check the battery voltage during the test if you have a second meter. If not, measure before or after.
When turning the pulley by hand the current draw should be between 2.3 and 2.7 amps.
That's from a 12/61 tech pamphlet. Alternator and Cranking Motor (Session 169) from the Master Technician's Service Conference
Field draw test with alternator on the bench.
You can do it on the bench as well.
Ignore the mess. Grounded field alternator.
1. Connect the alternator housing to ground. On the car that's already done by being mounted.
2. Set the multimeter. For this one it means plugging one of the leads into the 15 amp position and turning the dial.
3. Connect one lead of the the multimeter to the power and the other the alternator's field terminal.
Try to turn the pulley while taking the reading. Disconnect. Done.
A 'squareback' will draw a bit more. I've measured 3 amps on an original and 5.8 amps on a remanufactured one.
3 amps I wouldn't worry about. 6 amps I think is pushing the limits.
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Many of the square backs are also higher amp alternators as well. The parts store philosophy is that you are getting a better deal if the give you a higher amp alternator, so you should be happy.
However, your 50 year old wiring may not be up to the added current of a newer, higher amp alternator. Be careful or you could wind up with overheating in your wiring and connections.
If the field current is higher, that probably means it is a higher amp output alternator.
However, your 50 year old wiring may not be up to the added current of a newer, higher amp alternator. Be careful or you could wind up with overheating in your wiring and connections.
If the field current is higher, that probably means it is a higher amp output alternator.
The same voltage regulator runs all the different amp alternators. So the field current is no different, The internal windings of the alternator are.
The cars With few electrical accessories get the lower amp alternators the AC and power everything cars get the big amp unit’s.
The cars With few electrical accessories get the lower amp alternators the AC and power everything cars get the big amp unit’s.
No. Only amongst each line were the regulators the same. The optional 'fleet' alternators had regulators that were sometimes different. The '60 amp' Chrysler built squarebacks show a different regulator than the '50 amp' which was the highest normal option. The revised squarebacks came out later.
I’m not talking about fleet cars with different alts. I’m talking about a plain Jane stripper car vs a loaded with elect accessories car. Both have the normal looking finned alternator with different amp output. Same regulator.
OK OK stop the bullshit dude.
the guy has a 1969 Valiant. NONE of these parts you are bringing up ever came on a 69 Valiant and YOU KNOW IT!
you know exactly what I’m saying and you are looking for anything that is oddball to **** with me. Not working DH
the guy has a 1969 Valiant. NONE of these parts you are bringing up ever came on a 69 Valiant and YOU KNOW IT!
you know exactly what I’m saying and you are looking for anything that is oddball to **** with me. Not working DH
The point is this:
The 'normal looking alternator' that came in 1969 was removed from the car.
External appearences of repaired, rebuilt, and replacement alternators are no guarentee they have the factory internals nor meet the factory specs. In fact we have learned through experience that more and more 'replacement parts' are just whatever physically fits.
In the first post, 65Valium shows us two DIFFERENT alternators.
The one on top could be the original with a new rear bearing or replacement that looks similar.
We do not know what rotor is in it. It is the mainly the rotor that drives the field current.
It could have a rotor for a Chrysler built '60 amp' alternator even though that was never a standard option in '69 (or 70 or 71 or 72 or 73 excepted with the heated back glass). In fact if you go to look up replacement rotors, only '60 amp' rotors are what you will find being retailed now.
The second alternator shown is a revised squareback. That was never offered on any A-body. It didn't even exist yet.
I beleive he is using it to show that alternators with high draw field currents got special regulators.
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You may find that the squareback design limits the adjustable travel of the alternator, and you may need a shorter or longer belt to get it right should there be interference while trying to tighten the existing belt.
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