Points Side of Coil for Dwell Meter?
06-05-2008, 01:15 PM
#1
Team Owner
Thread Starter
Points Side of Coil for Dwell Meter?
It's been a long time since I have had a car with points and condensor....To set dwell I have to connect the meter (red wire) to the "points" side of the coil and ground (black wire) to an engine ground. Is the points side of the coil (-) or (+)?
06-05-2008, 01:31 PM
#2
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Negative side of the coil
Lars
Lars
06-05-2008, 01:33 PM
#3
Safety Car
I know the coils (-) side gets the hot 12v through a resister 6v wire. It has been a long time but I use to fire it up and turn my allen key left until it spudder, then right until spudder, then turn it to the middle of the two points. You won't get more than 3/4 turn from spudder to spudder
06-05-2008, 01:36 PM
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I know the coils (-) side gets the hot 12v through a resister 6v wire. It has been a long time but I use to fire it up and turn my allen key left until it spudder, then right until spudder, then turn it to the middle of the two points. You won't get more than 3/4 turn from spudder to spudder
You won't even get the dwell close by doing the procedure described - you can do that in an emergency to get a car running, but your timing and dwell will be way off. Set dwell to 30-31 degrees using a good quality dwell meter. After setting dwell, verify and adjust timing, since each one degree change in dwell changes timing by one degree.
Lars
06-05-2008, 03:05 PM
#5
Le Mans Master
Not to hijack this thread too badly but is there a write-up with pictures on how to install points in a distributor correctly? I took mine out years ago and went with an electronic conversion and damn if I remember how they go back in. 
All my manuals show the points already mounted but nothing about how the wiring goes. I'm not planning on going back to points but it would be nice to print out the procedure for future reference.
All my manuals show the points already mounted but nothing about how the wiring goes. I'm not planning on going back to points but it would be nice to print out the procedure for future reference.
06-05-2008, 04:23 PM
#6
Team Owner
Thread Starter
Red wire to (-) on coil worked fine.
I rather enjoyed that exercise; it's been many years. Since the 1974 arrived in April I been taking my time and going over it piece by piece. A learning experience for me but I like to fiddle about to ensure reliability this summer.
The R44 spark plugs were replaced by R45TS a couple of weeks ago. The old plugs were fouled by a bad carb. The pic shows a #70442xx replacement. Works fine. Nice shades on the plugs and pretty gray inside exhaust tips. So today I tackled the distributor.
The points were the uni- version and in pretty good shape. I will keep in the rear compartment as a spare set. The rotor and cap were burned but again not badly. The vacuum can is a B22. I can't recall Lars' rec on that can for a base 350 but it seems to work fine.
Replacement points were NAPA/Echlin #CS89 and the condensor #RR175SB. They seem to function nicely. Cap and rotor were also new. The dwell is at ~30; my meter is not terribly sophisticated but I would imagine that is close. Static timing is 10*BTDC. Idle is ~700rpm in Park and ~600rpm in Drive. I have slow creep in Drive with the TH400 so I consider that normal. No stalling.
All-in-all, I consider the time well spent. The car runs well.
I rather enjoyed that exercise; it's been many years. Since the 1974 arrived in April I been taking my time and going over it piece by piece. A learning experience for me but I like to fiddle about to ensure reliability this summer.
The R44 spark plugs were replaced by R45TS a couple of weeks ago. The old plugs were fouled by a bad carb. The pic shows a #70442xx replacement. Works fine. Nice shades on the plugs and pretty gray inside exhaust tips. So today I tackled the distributor.
The points were the uni- version and in pretty good shape. I will keep in the rear compartment as a spare set. The rotor and cap were burned but again not badly. The vacuum can is a B22. I can't recall Lars' rec on that can for a base 350 but it seems to work fine.
Replacement points were NAPA/Echlin #CS89 and the condensor #RR175SB. They seem to function nicely. Cap and rotor were also new. The dwell is at ~30; my meter is not terribly sophisticated but I would imagine that is close. Static timing is 10*BTDC. Idle is ~700rpm in Park and ~600rpm in Drive. I have slow creep in Drive with the TH400 so I consider that normal. No stalling.
All-in-all, I consider the time well spent. The car runs well.
Last edited by Paul L; 06-05-2008 at 07:25 PM.
06-05-2008, 06:33 PM
#7
Safety Car
That's not correct. The "-" side of the coil goes to ground through the points. The "+" side gets voltage through the resistor wire.
You won't even get the dwell close by doing the procedure described - you can do that in an emergency to get a car running, but your timing and dwell will be way off. Set dwell to 30-31 degrees using a good quality dwell meter. After setting dwell, verify and adjust timing, since each one degree change in dwell changes timing by one degree.
Lars
You won't even get the dwell close by doing the procedure described - you can do that in an emergency to get a car running, but your timing and dwell will be way off. Set dwell to 30-31 degrees using a good quality dwell meter. After setting dwell, verify and adjust timing, since each one degree change in dwell changes timing by one degree.
Lars
06-06-2008, 09:21 AM
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06-06-2008, 10:47 AM
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It works the same on dual points. The only difference is that you have to set one set of points at a time: de-activate one set by sticking a paper match between the point contacts to keep them open. Set the other set to 26 degrees. Then switch the match and set the first set to 26. With both sets running, you should get about 34 degrees of dwell.
06-06-2008, 12:05 PM
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Yes, that's correct. The dwell meter "+" (red) wire goes to the coil "-" terminal. The dwell meter "-" (black) wire goes to ground.
Lars
Lars
06-06-2008, 12:26 PM
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06-06-2008, 12:54 PM
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I think some early imports were positive ground. Also I believe Ford used the positive ground setup up to the end of WW2 or sometime in the late 40’s, not exactly sure.
I think the General always used negative ground system.
I think the General always used negative ground system.
06-06-2008, 12:55 PM
#16
Melting Slicks
06-06-2008, 12:59 PM
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06-06-2008, 01:15 PM
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06-06-2008, 01:16 PM
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Another way ...
There's a way to achieve the 30 degree dwell on a GM V-8 that's using points, without a meter. It will get you 29-31 degrees every time!
Use your 1/4" Allen Wrench still, for adjustment. If you have them roughly set and can start the car, then do this: Turn the Allen Wrench slowly clockwise, until the engine either misfires, or dies (whichever comes first).
Then back the wrench off 1/2 turn exactly and you will be at or extremely close to proper dwell.
I learned this from another mechanic 100 years or so ago when I got my first job at a shop. I was trying to set the points on my '56 Bel Air but didn't have a dwell meter yet. He taught me that trick and I used it. Over the years, I checked it on a few cars and I was always quite close to the perfect dwell of 30* 
Use your 1/4" Allen Wrench still, for adjustment. If you have them roughly set and can start the car, then do this: Turn the Allen Wrench slowly clockwise, until the engine either misfires, or dies (whichever comes first).
Then back the wrench off 1/2 turn exactly and you will be at or extremely close to proper dwell.
I learned this from another mechanic 100 years or so ago when I got my first job at a shop. I was trying to set the points on my '56 Bel Air but didn't have a dwell meter yet. He taught me that trick and I used it. Over the years, I checked it on a few cars and I was always quite close to the perfect dwell of 30*
06-06-2008, 01:24 PM
#20
Race Director
There's a way to achieve the 30 degree dwell on a GM V-8 that's using points, without a meter. It will get you 29-31 degrees every time!
Use your 1/4" Allen Wrench still, for adjustment. If you have them roughly set and can start the car, then do this: Turn the Allen Wrench slowly clockwise, until the engine either misfires, or dies (whichever comes first).
Then back the wrench off 1/2 turn exactly and you will be at or extremely close to proper dwell.
I learned this from another mechanic 100 years or so ago when I got my first job at a shop. I was trying to set the points on my '56 Bel Air but didn't have a dwell meter yet. He taught me that trick and I used it. Over the years, I checked it on a few cars and I was always quite close to the perfect dwell of 30*
Use your 1/4" Allen Wrench still, for adjustment. If you have them roughly set and can start the car, then do this: Turn the Allen Wrench slowly clockwise, until the engine either misfires, or dies (whichever comes first).
Then back the wrench off 1/2 turn exactly and you will be at or extremely close to proper dwell.
I learned this from another mechanic 100 years or so ago when I got my first job at a shop. I was trying to set the points on my '56 Bel Air but didn't have a dwell meter yet. He taught me that trick and I used it. Over the years, I checked it on a few cars and I was always quite close to the perfect dwell of 30*
