Stalls with electrical loads

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I will try bypassing ballast for test only and see what happens. I may have to hook up the tachometer I bought for it in 1987 to see what it actually idles at in gear:) Hate that tacked on look but 73's don't have rally gauge clusters. I am going to check ballast resistance when hot too, maybe it's just a crappy part. What part numbers/brands are considered prime?

I am still going to pull the carb and check T slots too, I remember this carb gave me a bad time when I first got it used several years ago off evil bay.

Thanks again for everyone providing inputs, electrical troubleshooting has never been my specialty.
 
Run a wire from the positive side of batt to the positive side of the coil. Start and see if problem is still there.
 
OK, long day yesterday with this thing, first off the fuel pump started leaking so had to replace that before doing anything else. Drove it around in hopes that may have contributed but of course no. So I removed the carb and here is what the T-Slot looked like:


After playing with the secondary adjustment this is where it ended up on the primaries:


I was able to go out about 1/4 turn more on mixture settings at idle. Car is about 90% where I want it. Stalling with accessories on does not seem to happen now. I also put degree tape on the balancer to more accurately check initial, total and vacuum advance. Car liked 16 initial with 36 total but detonation occurred at the upper end of the rev range. May go up a tad in Jet size on the primaries and see how she does. Settled back at 14 initital, 34 total for now and it does not rattle. Really odd how my other car did not mind either carb that sat on it but the 350SBC does have flat tops, zero decked block, running 9:5 CR to my mopars 8:00 with same cam specs: 270/280 .423/.414 cam. Cams only spec out 204/214 at .050 lift. Pretty mild cams considering the vacuum they pull at idle. Looks like the low compression engines need more throttle to idle and it just exposed too much T-slot.

Also, the voltage at coil in neutral, no accessories was about 7.5 volts. It's been a while since I had one I couldn't figure out on my own, thank you everybody for taking the time to post and help out. Big thanx to AJ for bringing up the T-slot issue.
 
Hooray. I was finally right about something. I'm so excited.But unfortunately, I was not actually right at all.
I was thinking the T-slot would be under exposed. Your pictures clearly show it to be over-exposed.So While I'd like to take credit, I cannot. I will,however, try to remember this for another time.
Congrats on your detective work
Don't be afraid to experiment with a later,slower, timing curve. Try not to force your combo into a preconceived box of what you think it should be able to withstand.Instead, work on trying to give her what she wants; and, not giving her any more than that.Sneak up on it. Good luck
 
Hooray. I was finally right about something. I'm so excited.But unfortunately, I was not actually right at all.
I was thinking the T-slot would be under exposed. Your pictures clearly show it to be over-exposed.So While I'd like to take credit, I cannot. I will,however, try to remember this for another time.
Congrats on your detective work
Don't be afraid to experiment with a later,slower, timing curve. Try not to force your combo into a preconceived box of what you think it should be able to withstand.Instead, work on trying to give her what she wants; and, not giving her any more than that.Sneak up on it. Good luck

You are too modest, if you had not brought up the T-Slot I would still be scratching my head:)
 
And you are my friend for life,with your kind words.
Now, let's talk a little about timing.
On the street
-You may never know the difference between optimum power timing, and 2 to 4 degrees short of optimum.And the reason is you are rarely in the rpm zone when it matters, and, rarely in that zone for more than a second or two,and,the engine is rarely loaded to the point where it might be working hard.
-Let's take an example; Suppose your warmed up 360 has street friendly gears of 3.23s, and a street friendly TC of 2400. This is enough gear and rpm, for that engine to roast 245/255s in that 73 Duster.So the engine is not working hard. As soon as it lights them up, the car accelerates away. You can even,for a short time, modulate the amount of tirespin. But around 50 to 55 mph that 8/1 RVcammed engine runs out of rpm, so you shift. The Rs drop to 3200 ish and off she goes again.But the speed limit is fast approaching. This whole thing takes less than 6 seconds, and the engine is never loaded very hard. And suppose the power timing was not optimum from 4000 to 5500. How much performance might you have lost? Well you were in that zone from 38 to 55 =17 mph. You never even got into it in 2nd gear. So out of the 6 seconds, you might have been in the zone for 1 to 1.5 seconds. Will that show up on your zero to 60 ET? probably.Are you gonna feel it?Not 2 degrees short you won't! Maybe not even 4 degrees short.
-The point is this; Why push the timing envelope that hard for a streeter? It doesn't take a lot of spark knock to destroy an engine.So sneak up on the optimum power-timing.
-If you wanna experiment, do so in the stall speed to 3600 zone. Get that figured out.That will make all the difference to a streeter.And not just the power-timing in this zone, but the part throttle timing, and the cruise timing,as well. Depending on the load/rpm, sometimes my 360 is liking 45 to 55 to 60 degrees of advance, in this zone. I'm not suggesting your 8/1 engine will like timings that large; Only that I give her what she wants, then she gives me what I want.
-If you have an EFI equipped car put a scanner on it and take it for a ride sometime. Have someone else drive while you eyeball the little screen.Watch what the timing is doing.Surprise,surprise.
 
And you are my friend for life,with your kind words.
Now, let's talk a little about timing.
On the street
-You may never know the difference between optimum power timing, and 2 to 4 degrees short of optimum.And the reason is you are rarely in the rpm zone when it matters, and, rarely in that zone for more than a second or two,and,the engine is rarely loaded to the point where it might be working hard.
-Let's take an example; Suppose your warmed up 360 has street friendly gears of 3.23s, and a street friendly TC of 2400. This is enough gear and rpm, for that engine to roast 245/255s in that 73 Duster.So the engine is not working hard. As soon as it lights them up, the car accelerates away. You can even,for a short time, modulate the amount of tirespin. But around 50 to 55 mph that 8/1 RVcammed engine runs out of rpm, so you shift. The Rs drop to 3200 ish and off she goes again.But the speed limit is fast approaching. This whole thing takes less than 6 seconds, and the engine is never loaded very hard. And suppose the power timing was not optimum from 4000 to 5500. How much performance might you have lost? Well you were in that zone from 38 to 55 =17 mph. You never even got into it in 2nd gear. So out of the 6 seconds, you might have been in the zone for 1 to 1.5 seconds. Will that show up on your zero to 60 ET? probably.Are you gonna feel it?Not 2 degrees short you won't! Maybe not even 4 degrees short.
-The point is this; Why push the timing envelope that hard for a streeter? It doesn't take a lot of spark knock to destroy an engine.So sneak up on the optimum power-timing.
-If you wanna experiment, do so in the stall speed to 3600 zone. Get that figured out.That will make all the difference to a streeter.And not just the power-timing in this zone, but the part throttle timing, and the cruise timing,as well. Depending on the load/rpm, sometimes my 360 is liking 45 to 55 to 60 degrees of advance, in this zone. I'm not suggesting your 8/1 engine will like timings that large; Only that I give her what she wants, then she gives me what I want.
-If you have an EFI equipped car put a scanner on it and take it for a ride sometime. Have someone else drive while you eyeball the little screen.Watch what the timing is doing.Surprise,surprise.

Good advice. FYI, I drove the car to work this morning with lights on, never took it out of drive. Running super smooth, no hiccups. I also noticed very little drop in idle speed when put into gear(running ported vacuum now of course) and the big surprise was how much cleaner it smells at idle and does not have that burn your eyes stench. This is the best the car has ever run.
 
Your ballast resistance check from several posts back is too high. 0.5-0.6 ohms cold is the stock spec. But to make sure you are measuring it accurately; short the ohmmeter leads together and record how much resistance is just in the leads. Then measure the ballast cold and subtract out the lead resistance to get an accurate number.

The MSD 0.8 ohm ballast is the closest to stock. The best is an NOS ballast from eBay, PN 2095501.

Very glad your secondary stop screw adjustments helped. Don't be afraid to do it again; it can take several iterations to get it optimum. The exposed primary T slot is not normal so I suspect you need some more adjustments on that.

And I agree with AJ on the timing; no point in pushing up to detonation for a street car and if you are 2 degrees off, you are preeeetty close. Be aware that you can get temp and humidity days that will promote detonation more easily; cool, dry fall days act like lowering fuel octane by 3-4 points versus a hot humid day! So some margin is wise.
 
Your ballast resistance check from several posts back is too high. 0.5-0.6 ohms cold is the stock spec. But to make sure you are measuring it accurately; short the ohmmeter leads together and record how much resistance is just in the leads. Then measure the ballast cold and subtract out the lead resistance to get an accurate number.

The MSD 0.8 ohm ballast is the closest to stock. The best is an NOS ballast from eBay, PN 2095501.

Very glad your secondary stop screw adjustments helped. Don't be afraid to do it again; it can take several iterations to get it optimum. The exposed primary T slot is not normal so I suspect you need some more adjustments on that.

And I agree with AJ on the timing; no point in pushing up to detonation for a street car and if you are 2 degrees off, you are preeeetty close. Be aware that you can get temp and humidity days that will promote detonation more easily; cool, dry fall days act like lowering fuel octane by 3-4 points versus a hot humid day! So some margin is wise.


I was wondering about that on the ballast, I have three of them, all test around 1.4-1.6 ohms cold. One of them is actually marked "1.2" on one of the terminals. Could swear my 74' Chiltons manual listed it as 1.5 ohms. Are there different values for different years, I would think the .5 ohm jobs would have been for points ignition? I really don't know so I will take your word for it though. I will look into procuring an MSD or NOS piece, wouldn't hurt to try one. Thanx again for the inputs, living in Florida I am well aware of Winter and Summer settings on the Carb and Ignition. What feels great at 70 degrees will rattle at 95 ambient.

By the way ran it with all accessories cranking, left it in gear at every light on the way home several times this week, never hiccuped once!! Still hard to believe a minor adjustment like that put it right.
 
The factory values for the coil resistors are in the back of the electrical section of various shop manuals. Once again, you can download those at MyMopar.

The '73 book shows .5--.6 for the COIL side and 1.6--1.79 for the ECU side

My 67 (points) book shows same thing.......... .5--.6 ohms
 
I was wondering about that on the ballast, I have three of them, all test around 1.4-1.6 ohms cold. One of them is actually marked "1.2" on one of the terminals. Could swear my 74' Chiltons manual listed it as 1.5 ohms. Are there different values for different years, I would think the .5 ohm jobs would have been for points ignition? I really don't know so I will take your word for it though. I will look into procuring an MSD or NOS piece, wouldn't hurt to try one. Thanx again for the inputs, living in Florida I am well aware of Winter and Summer settings on the Carb and Ignition. What feels great at 70 degrees will rattle at 95 ambient.

By the way ran it with all accessories cranking, left it in gear at every light on the way home several times this week, never hiccuped once!! Still hard to believe a minor adjustment like that put it right.
That's awesome, glad it got fixed! AJ gets a big pat on the back for his perception and experience. The comment on the ballast is just to make it as good as it can be; a 1.5 cold ballast resistance will run up around 5 ohms hot and is lowering the coil spark energy significantly. Perhaps info like in the Chilton's is part of the confusion....(Unless that is for the coil primary side resistance; 1.5 ohms would be normal for that number. And, FYI, a 0.6 ohm cold NOS ballast will read close to 2 ohms when hot.)
 
OK, long day yesterday with this thing, first off the fuel pump started leaking so had to replace that before doing anything else. Drove it around in hopes that may have contributed but of course no. So I removed the carb and here is what the T-Slot looked like:


After playing with the secondary adjustment this is where it ended up on the primaries:


I was able to go out about 1/4 turn more on mixture settings at idle. Car is about 90% where I want it. Stalling with accessories on does not seem to happen now. I also put degree tape on the balancer to more accurately check initial, total and vacuum advance. Car liked 16 initial with 36 total but detonation occurred at the upper end of the rev range. May go up a tad in Jet size on the primaries and see how she does. Settled back at 14 initital, 34 total for now and it does not rattle. Really odd how my other car did not mind either carb that sat on it but the 350SBC does have flat tops, zero decked block, running 9:5 CR to my mopars 8:00 with same cam specs: 270/280 .423/.414 cam. Cams only spec out 204/214 at .050 lift. Pretty mild cams considering the vacuum they pull at idle. Looks like the low compression engines need more throttle to idle and it just exposed too much T-slot.

Also, the voltage at coil in neutral, no accessories was about 7.5 volts. It's been a while since I had one I couldn't figure out on my own, thank you everybody for taking the time to post and help out. Big thanx to AJ for bringing up the T-slot issue.

Edit: My cam specs were improperly listed, actual is 270/280 .420 I/.443 E 204/214 lift @.050. This has been my cam of all seasons choice for everything from 305,350 and 383 Chebbies and the same grind spec for my 360 Duster. Tons of torque, good power, fair economy and 100,000 mile plus durability.
 
That T-port sync looks pretty good; from square to slightly taller than wide.If the secondaries had to be cranked quite far open to achieve this, then the engine wants more initial timing. But as you have discovered, with your current dizzy set-up,this causes the dreaded detonation.
The cure for that is to limit the centrifugal advance. You say your advance is now 14/34. Well that means there is 34 - 14 =20* centrifugal. If you rework the dizzy cam by shortening the advance slots, such that the new centrifugal is say 16*, Then when you reinstall it and reset the power timing to 34*, then the initial will be 34 - 16 =18*. The engine rpm will go up 50 to 150 rpm, depending on how it liked the new idle timing. This will allow you to close the secondaries back to a normal idle speed, and reset the mixture screws. This should improve tip-in from idle.
On the otherhand; if the secondary cracking screw is only open 1/2 to 1.5 turns, then you are pretty close. Somewhere after 2 turns, if the rear has no idle fuel compensation, then the carb often exhibits a problematic idle, a stinky exhaust and,lean tip-in, that requires pumpshot fiddling. I try to run as little pumpshot as possible cuz well, pumpshot sucks fuel.The extra idle timing also fills out the low-speed timing curve and often helps make a snappy response, until the timing is all in.And best of all, the extra cruise timing and leaner A/F at cruise will help get some Mpgs.
 
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