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New 70 Duster barely starts, and backfires or spews soot
https://slantsix.org/forum/viewtopic.php?t=53793		 Page 3 of 6
Author:  killnine [ Mon Nov 11, 2013 8:51 pm ]
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OK, now I'm really in a fix and need some help! I got the bright idea to play with the temperature sensor, and before replacing, I thought I could test the old one by grounding it out. I grounded it out, and I guess I did that for way too long, because after I didn't see it move the gauge, and I replaced it, I went to start it up and the engine cranks once or twice then the starter sounds like it's the only thing spinning and it's locked up. I looked around to see what might have happened and I saw what I think is the battery terminal on the alternator was melted. The black plastic ring around it was fried. I don't even know what to think at this point. Why would a fried alternator make the engine act like it was seized? The only other thing I had done before this when it was running was mess with the dizzy to see what effect it had, but I had set it back to its original position. I tried moving it a bit but of course this didn't help any.
Author:  Fopar [ Mon Nov 11, 2013 8:57 pm ]
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"the battery terminal on the alternator was melted. The black plastic ring around it was fried"

This would leave me to suspect a loose nut on the post on the alternator, this would let it act like an arc welder.

Richard
Author:  killnine [ Mon Nov 11, 2013 9:35 pm ]
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Quote:
"the battery terminal on the alternator was melted. The black plastic ring around it was fried"

This would leave me to suspect a loose nut on the post on the alternator, this would let it act like an arc welder.

Richard
It's nice and tight. Whatever it was it was caused by a short or some kind of problem maybe causing an overload of output on that terminal, which I believe is the output terminal.

After calming down a bit, I went out and checked battery voltage, and it's a little low but fine, around 12.7. I couldn't find any other fried or melted wires. I haven't loosened the alternator yet, but maybe it's seized and that's the problem. I can turn it over and it sounds like it's cranking once, but then the starter just spins out, like the bendix isn't engaging or it's backing off after one hit.
Author:  mattelderca [ Tue Nov 12, 2013 5:14 am ]
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Well, no matter what I do the vacuum advance fitting on the carb provides vacuum, despite supposedly being ported. If I adjust the curb idle any lower it will die, and it will be a completely closed throttle. It's the same amount of vacuum as non-ported. so something is definitely very wrong. Considering I just went through most of the top end of the carb, and carb spray around everything doesn't show any leaks, I guess maybe it's something in the bottom end of the carb?
Could this be a lean burn carb?
Author:  killnine [ Tue Nov 12, 2013 8:12 am ]
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Well, no matter what I do the vacuum advance fitting on the carb provides vacuum, despite supposedly being ported. If I adjust the curb idle any lower it will die, and it will be a completely closed throttle. It's the same amount of vacuum as non-ported. so something is definitely very wrong. Considering I just went through most of the top end of the carb, and carb spray around everything doesn't show any leaks, I guess maybe it's something in the bottom end of the carb?
Could this be a lean burn carb?
I don't think so. There are no electrical connections. The model is at the top of the thread, and a picture on page 2.

I'm not sure if I've mentioned it yet, but I think I'm supposed to be able to tune the throttle valve to be pretty much shut and it would continue to run. I know some models of the BBD had an idle air bypass that would help with this, but I don't know if mine does. When I back off the curb idle enough it just dies, so I'm thinking the curb idle is too far open when it is adjusted enough to idle, and so it starts producing vacuum even at ported and maybe causing other issues off idle.
Author:  wjajr [ Tue Nov 12, 2013 10:35 am ]
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With throttle plates closed at idle, say 900 rpm or lower, there should be no vacuum above the throttle plate(s) that the orifice leading to ported vacuum tap.

After viewing carburetor image on page 2, there looks to be a vacuum port covered by a red cap facing the fire wall. If this is a vacuum port, it would be the one used for ported vacuum because it is located above the throttle plate(s) and will see close to manifold vacuum only when throttle is open and engine is off idle at higher rpm.
Author:  Reed [ Tue Nov 12, 2013 11:02 am ]
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Quote:
With throttle plates closed at idle, say 900 rpm or lower, there should be no vacuum above the throttle plate(s) that the orifice leading to ported vacuum tap.

After viewing carburetor image on page 2, there looks to be a vacuum port covered by a red cap facing the fire wall. If this is a vacuum port, it would be the one used for ported vacuum because it is located above the throttle plate(s) and will see close to manifold vacuum only when throttle is open and engine is off idle at higher rpm.
No, see my post above. That is the idle air enrichment valve.

I think the time has come to completely disassemble the carburetor, clean it, and reassemble it using all new gaskets and making sure the gaskets match the holes in the carb body.

Also, can you post a picture of the choke linkage on the carb? You may have a v-8 carb that won't work with the slant thermostatic choke pulloff without some modification.
Author:  killnine [ Tue Nov 12, 2013 11:51 am ]
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Quote:
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With throttle plates closed at idle, say 900 rpm or lower, there should be no vacuum above the throttle plate(s) that the orifice leading to ported vacuum tap.

After viewing carburetor image on page 2, there looks to be a vacuum port covered by a red cap facing the fire wall. If this is a vacuum port, it would be the one used for ported vacuum because it is located above the throttle plate(s) and will see close to manifold vacuum only when throttle is open and engine is off idle at higher rpm.
No, see my post above. That is the idle air enrichment valve.

I think the time has come to completely disassemble the carburetor, clean it, and reassemble it using all new gaskets and making sure the gaskets match the holes in the carb body.

Also, can you post a picture of the choke linkage on the carb? You may have a v-8 carb that won't work with the slant thermostatic choke pulloff without some modification.
It's a manual choke, with the vacuum pulloff. I'll post a pic. I generally start it by pedal, close choke, release pedal, start engine.

I agree about the carb teardown. I've torn down the top end and cleaned and replaced and reset to spec, but I haven't taken the body off the intake. I think I need to do that and verify a few things. It's possible they used the wrong gasket, or there is a leak at the base.
Author:  killnine [ Tue Nov 12, 2013 11:54 am ]
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As to my alternator issues, here's what I think has happened.

Something, possibly me grounding the temp sender, has caused a current spike in the system. Whatever happened caused enough current at the alternator output to melt the surrounding plastic, and probably fried the fusible links to the starter relay (those I haven't checked yet). Also, I think this might have caused enough internal damage to the alternator that it is currently seized, and so when I try to start it, the starter sees enough resistance that it immediately backs off the ring gear, and just spins.

I'll verify by checking the fusible links, and releasing the alternator and trying to spin it. I'm also a but concerned about the voltage regulator, since it possibly could have seen high current. Anyone have a method of testing the VR?
Author:  Reed [ Tue Nov 12, 2013 11:55 am ]
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OK- a manual choke removes the thermostatic choke pulloff form the equation. Just be sure the choke opens the choke valve fully.
Author:  WagonsRcool [ Tue Nov 12, 2013 4:00 pm ]
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seemed to be sucking more air than it should, so I couldn't tell at all if it was bled or not in the front. I didn't do anything to the rear because the bleed fittings were some other size I didn't have an offset bleeder wrench for.
I've never had any luck using vacuum bleeders- You're either sucking air past the bleeder screws (I take them out & put anti-seize on the threads) or past the cup seals in the wheeel cylinders. Brake systems are designed to work with positive pressure, not vacuum.

As for your starter, it sounds like you have some potentially serious electrical problems. If the starter engages briefly then "stops" (as if you let off the key) then you might have a heat damaged connection somewhere between the battery & the ignition switch. The electrical system can't supply enough power to keep the starter applied. You need a voltmeter connected to the starter terminal to see what's going on.

If the engine turns briefly but the starter motor continues (sounds like on old electric drill)- that would be indicative of a failing bendix drive
Author:  killnine [ Wed Nov 13, 2013 5:10 pm ]
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seemed to be sucking more air than it should, so I couldn't tell at all if it was bled or not in the front. I didn't do anything to the rear because the bleed fittings were some other size I didn't have an offset bleeder wrench for.
I've never had any luck using vacuum bleeders- You're either sucking air past the bleeder screws (I take them out & put anti-seize on the threads) or past the cup seals in the wheeel cylinders. Brake systems are designed to work with positive pressure, not vacuum.

As for your starter, it sounds like you have some potentially serious electrical problems. If the starter engages briefly then "stops" (as if you let off the key) then you might have a heat damaged connection somewhere between the battery & the ignition switch. The electrical system can't supply enough power to keep the starter applied. You need a voltmeter connected to the starter terminal to see what's going on.

If the engine turns briefly but the starter motor continues (sounds like on old electric drill)- that would be indicative of a failing bendix drive
I agree about the bendix. I know it's supposed to back off the gear when it is overrun by the engine starting, but does it back off when it encounters resistance, like if the alternator were seized up or something else causing too much load? Somehow I doubt it, since turning the engine over is a lot of load to begin with. Something electrical definitely happened. I'm starting to wonder if adjusting the dizzy rotation caused some kind of mishap. Maybe the bluestreak cap and echlin rotor contacted each other or something. I'll be looking into that.
Author:  killnine [ Wed Nov 13, 2013 8:01 pm ]
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Hmm, this thing has a 1965 date coded Lester alternator and an electronic wells VR. Not sure about all that.
Author:  killnine [ Thu Nov 14, 2013 9:38 am ]
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Excuse my ignorance, but this is making less sense the more I trace things.

The alternator has three wires, the battery output of course, and two spade terminals. One is marked FLD, and is blackish, maybe really dark blue, and the other is marked GRD, and is green. There is also a non-used hole on the side opposite the GRD side marked also GRD. The spade marked FLD is opposite the battery output terminal. On the triangle style regulator connector, I have a green wire connected to the bottom right, which should be FLD, and is presumably the green wire going to the GRD on the alternator, and the IGN wire is more obviously blue or purplish. After that, on both sides, the wires go into a wrap that I'd prefer not to undo right now. I can do some continuity tests later.

Now in my reading I know this could be either a grounded field or isolated field alternator, given the datestamp (1965), but I have no idea if any isolated field alternator would actually have a FLD terminal marked GRD.

Was this done completely wrong? I mean if this alternator could actually work with a newer regulator I might attempt to verify it isn't fubarred and keep it, but if this is all wrong I need to do some replacing.

The regulator has the new style connector, it's a silver box, and it's a Wells.

The alternator, as mentioned previously, is a Lester, 1965 stamped.

I should also mention that the terminal marked GRD which is causing all the confusion, the connector is insulated, where it screws into the case, it has some plastic type insulation underneath it, where the FLD does not have the same.
Author:  mattelderca [ Fri Nov 15, 2013 7:39 am ]
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A picture of the alternator connections would help, but the wiring sounds correct. The unused hole marked GRND is probably just a threaded hole for a ground wire, which is a good idea to have.
The dark wires on FLD and at the regulator should be Blue and they join together in the harness, they should have 12 volts switched by the ignition.
The green wire from the regulator should indeed go to the field ground on the alternator, which should not be grounded to the case. You can test that with an OHM meter, remove both field wires and meeter between them and the case, you should see infinet or open on the meter.
Again, the wiring sounds fine it is just the type of connectors you are describing that sound a bit off, a picture would prove them.
The melted battery connection might have just been a loose connection, or it could have been caused by a bad diode or reversed booster cable connection. It should not have been caused by shorting a gauge lead.

Here is a simple video that will show the connections and a simple way to prove that the alternator is working and test the connections. Make sure you only do the test momentarily, and I use the regulator body for ground to prove that it is grounded as well. The regulator ground is important and should really have an extra wire to ground it and the alternator together.
http://youtu.be/ZzBbpTtVF-4
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