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Need Dual Point Assistance

6

67 GTX

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Tried to get the dual point dizzy going in my 67 GTX 440 today, but had no luck. I used all NOS parts, and cleaned and made sure they didn't have any corrosion on them. I was able to get 29 dwell on one set of points, and the car ran, but rough.

Could not get the car to run on the other set of points. During cranking, I was able to get 30 dwell, but the motor wouldn't fire.

I am getting a strong spark from the coil, but the car won't fire. I've played with the timing (advanced and retarded it), but still no luck.

Can anyone give me any pointers?

I am blocking one point off with a piece of cardboard while I work on the other.
 
I ended up pulling one set and running mine as a regular single point distributor, never had a problem.
 
I have never set or installed dual points.
But i know that you should have spark as the second point opens, (breaking the circuit generating a spark)) Both would be open then.
Then the first point closes before the 2nd point can completing the circuit sooner than only one point could. So you get a longer dwell period and more saturation in the system because the circuit gets closed sooner, increasing dwell.
So you do need to be sure that the dist. Is in the correct position and the crank in correct position.
Also i believe the gap is supposed to be the same for both points.
At least that's how I understand it.
I just use electronic ignition. MUCH BETTER AND EASIER.
Longer dwell, hotter spark, no hassles, no gapping points. Pertronics is great.
Also you should get a hot coil, really good plug wires and
Get good plugs and gap them as wide as you can till they start missing then close them up a little.
 
OK I run into this also on occasion, first is the small ground strap still in place to the advance plate and second make sure the point contacts are clean, really clean, hit it with some sandpaper folded with the points closed like the cardboard and dress them.
 
I have no experience with the dual point system. But I will add, you can check the continuity of each set with an ohm meter to be sure they are clean.
In the closed position, put one lead from meter to the wire terminal on the point, and one lead to the body of distributor.
Should show a complete circuit
 
67 GTX said:
Could not get the car to run on the other set of points.
Click to expand...
Guess you know, on dual points, the primary set breaks first, creating the spark. Second set, secondary opens before the primary set closes, all in all, giving a 'longer' spark.
Easy to figure which set is which, rotating the cam, and see which set opens first. Set the gap for both sets at .021-.022, and try it, including the dwell for each set. Be sure points contact surfaces are clean!
If it's running rough, might need a new condenser.
 
The way I read it Miller the "other" set is not making the closed circuit? Yes Condensers do fail but would be the same for both sets so thinking it is fine since it is running on one set. Could be weak though for sure.
 
HALIFAXHOPS said:
The way I read it Miller the "other" set is not making the closed circuit? Yes Condensers do fail but would be the same for both sets so thinking it is fine since it is running on one set. Could be weak though for sure.
Click to expand...
Or no ground strap and it has just enough ground through the ball bearings in the advance plate have seen that also. Prob something simple like oil on the contact
 
HALIFAXHOPS said:
The way I read it Miller the "other" set is not making the closed circuit?
Click to expand...
Hard to say, if things are set right. If both points are set the same, both should be opening, and closing. Yep, oil, grease, dirt will keep it from acting right.
What dual point distributor are we talking about?? That would help. Advance work??
 
I am referring to the Prestolite cast iron one.

I do have the grounding strap going from the advancing plate to one of the points.

I did clean the points before I installed them.

I do not believe I am 180 but at this point I'll try anything. The car was running at one point (albeit very rough) so unless my initial timing is way off I bet I'm not 180 off.

I did re-index the cam gear 2 notches in order to get it to match what the old single point was like. Once I did that, the car ran (where I mentioned it was very rough).

Another thing that is weird, whenever I get the car to run, it sounds ok at first. Then the longer you wait, the engine just gets rougher and rougher till it ultimately dies (talking 5 minutes or so).
 
67 GTX said:
I am referring to the Prestolite cast iron one.
Click to expand...
Ahh, okay. Heard of 'em, but my first was an aluminum housing Prestolite dual point.

From how your describing things, maybe a grounding issue. Still maybe the condenser. Might check distributor ground, to the engine itself, ground strap you've mentioned, and so on. The points need a ground connection, via how the mount in, on one side of the points. Should have it, but won't hurt to check. Off hand, only things I can think of.
Cap and rotor in good shape? How about your plug wires?

Like I mentioned before, points, one set primary (first to open)...if you have the engine timing, at the initial timing you want at the timing marks, drop the distributor in, rotor towards #1 plug wire on the cap. Rotate the distributor housing, until the primary set of points is on the verge of cracking open. Go from there.
 
I would pull the secondary set out and lay it on a piece of cardboard (non conducting material) and then slip another piece of thin cardboard or paper between the points.
Then read the continuity between the top point and the lower point with an ohm meter to see if the two half's of the points are making contact with each other.
If they are, the insulator on the pivoting shaft or the little plastic/phenolic washer(s) is not isolating the two parts from each other. This will short out the spark for sure if it is not made correctly.

I have ran into this situation several times in the past. You would be surprised how many Brand New set of points are manufactured this way, especially from overseas.

Good luck, be blessed, and God Bless America.

Mike
 
Just to ad to what I said in the above post.
I have found some points to seem to be ok when tested with the cardboard in between the points.

Until i opened the points while testing the set with the ohm meter, putting them through its full travel (witch is not much). That is when sometimes they would short out in a certain position.

It maybe worth an inspection.

Mike
 
It's a combination between the two points to get your desired dwell setting. (Last paragraph)

"For Dual Point distributors there is a bit more effort involved. You can still set the point gap on the "primary" point set in the distributor (see note below), but you might as well forget the secondary point set at this moment.

NOTE: Primary vs. Secondary (or trailing) point set. The Primary point set is the "first" point to open in relation to the rotation of the engine and it's placement in the distributor housing. If you look into the distributor from the top, you will notice that the pair of points are nested to one side of the distributor housing. No matter the rotation of your distributor, the first point set that opens is called the primary set. The second one that opens is called the secondary (or trailing) point set. When the primary point opens, watch it ... before it closes, the secondary point will open.
To set dual point ignitions you first block the "secondary" point set. You can block it by either not having it in the distributor, or using a thin piece of cardboard such as a matchbook cover between the contacts of the secondary point set. With the same (Safety Precautions) as above: ignition coil wire removed, the cap and rotor off the distributor, and a dwell meter properly connected to the coil, you can spin the engine. The best way to do this is with a remote starter button. The only other way to do this is with someone assisting you. Crank the engine and watch the reading on the dwell meter. You will be setting ONLY the primary point to the required setting at this time.

After you have set the primary point set to the required dwell, install or unblock the secondary point set. You will now spin the engine again and by adjusting ONLY the secondary point set, adjust the the secondary point so that the dwell reading matches the "combined" dwell specification. You do not have to touch the primary set again.

Example: You have a V8 engine application and your dwell settings are 26° (each point), and a combined setting of 33° ± 2°. You will set the primary point to 26° with the secondary set blocked, then by adjusting ONLY the secondary point set, adjust it so the dwell reads 33° (or between 31° and 35°)."

https://www.jalopyjournal.com/forum...o-set-gap-on-a-dual-point-distributor.459917/
 
The getting hot and dying is the condenser for sure. Still have to figure out the other set of points though. Stupid question they aligned with good spring pressure?
 
khryslerkid said:
It's a combination between the two points to get your desired dwell setting. (Last paragraph)

"For Dual Point distributors there is a bit more effort involved. You can still set the point gap on the "primary" point set in the distributor (see note below), but you might as well forget the secondary point set at this moment.

NOTE: Primary vs. Secondary (or trailing) point set. The Primary point set is the "first" point to open in relation to the rotation of the engine and it's placement in the distributor housing. If you look into the distributor from the top, you will notice that the pair of points are nested to one side of the distributor housing. No matter the rotation of your distributor, the first point set that opens is called the primary set. The second one that opens is called the secondary (or trailing) point set. When the primary point opens, watch it ... before it closes, the secondary point will open.
To set dual point ignitions you first block the "secondary" point set. You can block it by either not having it in the distributor, or using a thin piece of cardboard such as a matchbook cover between the contacts of the secondary point set. With the same (Safety Precautions) as above: ignition coil wire removed, the cap and rotor off the distributor, and a dwell meter properly connected to the coil, you can spin the engine. The best way to do this is with a remote starter button. The only other way to do this is with someone assisting you. Crank the engine and watch the reading on the dwell meter. You will be setting ONLY the primary point to the required setting at this time.

After you have set the primary point set to the required dwell, install or unblock the secondary point set. You will now spin the engine again and by adjusting ONLY the secondary point set, adjust the the secondary point so that the dwell reading matches the "combined" dwell specification. You do not have to touch the primary set again.

Example: You have a V8 engine application and your dwell settings are 26° (each point), and a combined setting of 33° ± 2°. You will set the primary point to 26° with the secondary set blocked, then by adjusting ONLY the secondary point set, adjust it so the dwell reads 33° (or between 31° and 35°)."

https://www.jalopyjournal.com/forum...o-set-gap-on-a-dual-point-distributor.459917/
Click to expand...

Very nice way to explain it!
 
HALIFAXHOPS said:
the small ground strap still in place to the advance plate
Click to expand...
Good info, guys!
Thinking on the fly, I don't recall the mentioned small ground strap. Wonder if, where it's connected, could be shorting out one set of points. Should be an easy check, from ground to the circuit side of the points. Points open, should not have circuit to ground, if that makes any sense.
 
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