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Old 01-09-2016, 10:42 PM   #1
1972Blaze
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Why can't I set my dwell angle properly?

I put in a new set of points (along with rotor, cap, condenser, wires and plugs). I checked them and the gap was correct at .019. Once running I checked with a dwell meter and it reads right at 40 degrees. I tried to adjust the dwell by turning the screw both directions. There was a noticeable change in the idle speed, but there was almost no movement on the dwell meter. It stayed very close to one side or the other of 40 degrees. I did this with two sets of points with the same result. I want to believe it is a bad meter, but it is a pretty basic piece of equipment. Is there anything mechanical I should check before investing in a new meter? This is a new to me distributor. Would wear on the distributor shaft cam cause this?

By the way, I know it will be recommended, but I do not want to change to HEI.

Thanks for any help.
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Old 01-09-2016, 11:07 PM   #2
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Re: Why can't I set my dwell angle properly?

I would (personally) never stick a big HEI in one of these trucks if originality was any kind of goal. But I still also would never run points. That's why they invented the Pertronix II. Or heck, the Petronix III, though our tachs don't always like them.

I'd sure spend the money on an under-cap transistor breaker before a new dwell meter! Unless you do plan to work on a lot of points vehicles... but I gap them with a match book cover to get them running long enough to replace the points.

Sorry I can't help with the actual underlying problem though.
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Old 01-09-2016, 11:14 PM   #3
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Re: Why can't I set my dwell angle properly?

dwell should be 30 deg - is that what you're trying to adjust it to? are the points tight to the plate? Which screw are you adjusting? More detail and maybe someone can chime in with the silver bullet.
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Old 01-09-2016, 11:19 PM   #4
1972Blaze
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Re: Why can't I set my dwell angle properly?

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dwell should be 30 deg - is that what you're trying to adjust it to? are the points tight to the plate? Which screw are you adjusting? More detail and maybe someone can chime in with the silver bullet.
Yes, trying to adjust to 29 or 30. The points are tight to the plate. Adjusting the 1/8" hex screw on the points.

Thanks.
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Old 01-09-2016, 11:42 PM   #5
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Re: Why can't I set my dwell angle properly?

thx. now I can see why you're asking! I'm stumped too. So you have another points care you can check the dwell on to confirm the meter is good?
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Old 01-09-2016, 11:42 PM   #6
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Re: Why can't I set my dwell angle properly?

i vote for the meter...you're obviously changing the adjustment if the idle is changing....some of the chain auto part stores like auto zone loan tools,i'd try that before i bought one...back in the day we'd just adjust it by ear till the idle was highest (probably not right,but thats how i was taught...never rechecked one with a meter...wonder if it was close)
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Old 01-09-2016, 11:52 PM   #7
1972Blaze
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Re: Why can't I set my dwell angle properly?

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thx. now I can see why you're asking! I'm stumped too. So you have another points care you can check the dwell on to confirm the meter is good?
No, my other car is a Transistorized Ignition car.
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Old 01-10-2016, 12:46 AM   #8
Alex V.
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Re: Why can't I set my dwell angle properly?

Just covering a base - but make sure you have the meter hooked up right. Last time I checked my dwell I coulda swore both leads went on the coil, and my meter was reading about 40 no matter what IIRC. Hooked the ground to the battery after re-checking the instructions and that got everything straightened out.
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Old 01-10-2016, 01:08 AM   #9
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Unhappy Re: Why can't I set my dwell angle properly?

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Just covering a base - but make sure you have the meter hooked up right. Last time I checked my dwell I coulda swore both leads went on the coil, and my meter was reading about 40 no matter what IIRC. Hooked the ground to the battery after re-checking the instructions and that got everything straightened out.
You might be on to something…Clearly it has been far too long since I used my dwell meter. Thanks for the help.
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Old 01-10-2016, 01:25 AM   #10
4 Wheelin Fudpucker
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Re: Why can't I set my dwell angle properly?

Petronics are known the fail in damp weather, like here. They might be good for CA and summer time, but Ive seen too many fail to depend of them.

A set of points, screwdriver and a match book and your back down the road.
Grew up with points, Im not afraid of them.

Tho both of mine have HEI factory distributors in them.
I have a rebuilt points set up in a Faraday cage, just for giggles.
and can swap it out in 30 minutes.

As far as your dwell, pull the cap and see if the points are moving in and out. The screw assy may have stripped
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Old 01-10-2016, 10:48 AM   #11
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Re: Why can't I set my dwell angle properly?

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You might be on to something…Clearly it has been far too long since I used my dwell meter. Thanks for the help.
I connect one to engine ground and the other lead to + coil .
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Old 01-10-2016, 12:57 PM   #12
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Re: Why can't I set my dwell angle properly?

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I connect one to engine ground and the other lead to + coil .
Try - coil, all your doing is measuring voltage to the coil
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Old 01-10-2016, 02:34 PM   #13
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Re: Why can't I set my dwell angle properly?

You have to connect one lead to the neg side of coil that goes to the dist. The other is to ground. If you set the points at .019 the dwell will be correct. Another way to set them is turn the adj. in slowly till the engine dies. Then turn it 1/2 turn out.
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Old 01-10-2016, 05:24 PM   #14
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Re: Why can't I set my dwell angle properly?

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Originally Posted by 4 Wheelin Fudpucker View Post
Petronics are known the fail in damp weather, like here. They might be good for CA and summer time, but Ive seen too many fail to depend of them.
I have them in every old vehicle I have.

I have never had a failure.

I live in SEATTLE.
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Old 01-10-2016, 05:52 PM   #15
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Re: Why can't I set my dwell angle properly?

I'm still running points. If your dwell meter is reading 40 and adjustments vary idle then set at 40% .and run it. Should be 30% but if the meter is off no problem. If the points are off it'll burn 'em and the coil after awhile. Then you can throw electronic's at it. No sense throwin' big money at it!
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