Dual point distributor ID question

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KosmicKuda said:
Replacement vac advance pods have different total advances available. There should be a number stamped on the flat linkage arm. IIRC it's advance in crankshaft degrees but don't quote me.

Where's @Halifaxwhen you need him.
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For regular Mopar distributors. Those vac advance units for the old dual points are next to impossible to find.
 
mvh said:
I'm pretty sure the distributor hasn't been messed with other than high mileage. Oh, except the vacuum advance was replaced... possibly with a different washer pack, but it doesn't seem to be the problem, anyway. Just curious -- what is the effect of adding/subtracting washers to the vacuum advance? Does a thicker washer decrease the amount of advance, or the other way around? They don't discuss this in the FSM at all.
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You would have to ask Halifaxhops about that.
 
My 67 273 is a CAP car.

The book says 5 ATDC initial.

I have mine set to 0. The centrifugal and vacume advance comes in so fast that it works well.

I also have the green timming off delay devise set so it is in operable.

That is something to check, if you still have it, that it is not leaking internally allowing manifold vacuumed the the advance can.


My stock single point dist had an issue with the dwell dropping off, due to the vacuume advance moving the breaker plate, so much that the engine would miss fire at 1200 to 2000 rpm in Neutral.

I recently bought, refurbished, and installed a Prestolite dual point. Due to the breaker plate design the dwell remains the same regardless of vacuume advance and no more misfire.

Be sure the ground wire from the lower breaker plate to the upper plate is intact. Otherwise the ground path goes through the ball bearing in the center of the breaker plate
 
Yeah, the dual points have an adjustable vacuum pot. You unscrew the nipple and there is an o-ring and a short stack of washers, or one thick washer. But I have never come across any info about how you actually adjust these. When the original vacuum pot failed, I took it apart to see what the washer pack looked like, to compare it to the NOS one I found on eBay. I made sure it was the same. Now I have 2 spare distributors, one CAP and one not, both with good advance pots. But anyway, the vac advance doesn’t seem to be the issue.
 
Dana67Dart said:
My 67 273 is a CAP car.

The book says 5 ATDC initial.

I have mine set to 0. The centrifugal and vacume advance comes in so fast that it works well.

I also have the green timming off delay devise set so it is in operable.

That is something to check, if you still have it, that it is not leaking internally allowing manifold vacuumed the the advance can.


My stock single point dist had an issue with the dwell dropping off, due to the vacuume advance moving the breaker plate, so much that the engine would miss fire at 1200 to 2000 rpm in Neutral.

I recently bought, refurbished, and installed a Prestolite dual point. Due to the breaker plate design the dwell remains the same regardless of vacuume advance and no more misfire.

Be sure the ground wire from the lower breaker plate to the upper plate is intact. Otherwise the ground path goes through the ball bearing in the center of the breaker plate
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Yeah, BTDT with the ground wire.
 
mvh said:
Yeah, the dual points have an adjustable vacuum pot. You unscrew the nipple and there is an o-ring and a short stack of washers, or one thick washer. But I have never come across any info about how you actually adjust these
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Fords of the time had them too.

You can change:
  1. The spring (stiffer softer)
  2. The limiter ( more or less total advance)
  3. The washers (when the advance starts to come in)
 
I have dealt with a broken ground wire in the past... "Been There, Done That".

What I am curious about is, what is the effect of these alterations?

1. Stiffer spring = advance comes in more slowly (seems obvious). No idea where you would get a replacement spring.
2. The limiter — not sure what this is, or how you would adjust it
3. The washers — more washers = what? Advance comes in faster, or slower? My impression was that this was the only user adjustment.
 
mvh said:
I have dealt with a broken ground wire in the past... "Been There, Done That".

What I am curious about is, what is the effect of these alterations?

1. Stiffer spring = advance comes in more slowly (seems obvious). No idea where you would get a replacement spring.
2. The limiter — not sure what this is, or how you would adjust it
3. The washers — more washers = what? Advance comes in faster, or slower? My impression was that this was the only user adjustment.
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You need parts? Contact @halifaxhops , You need repair? Contact Halifaxhops. You have questions? Contact Halifaxhops!
 
mvh said:
1. Stiffer spring = advance comes in more slowly (seems obvious). No idea where you would get a replacement spring.
2. The limiter — not sure what this is, or how you would adjust it
3. The washers — more washers = what? Advance comes in faster, or slower? My impression was that this was the only user adjustment
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There were tune kits in the past look on eBay for nos kits.

In the Ford version at least there was a plastic tube inside the spring. Shoerte allows more vac advance longer less.

A coil spring as a particular spring rate lbs per inch. It is basically linear.

If a spring has a rate of 5 lbs per inch the diagram will move 1 inch with 5 lbs of suction, 2 inches with 10 lbs. ( These numbers are just numbers for illustration)

Now you take the same 5 lbs per inch spring and compress it 1 inch (preload)
Now it will take 10 lbs to move it the first inch. The washers do not change the spring rate they just set the ride height so to speak.


So for tuning purposes. If you want your vac advance to start later add washers.

If you want it sooner remove washers.

If you want it to advance quicker, lighter weight spring, slower heavier spring.


I haven't had a distributer Ford in decades. But I still have these parts.


PXL_20230329_010924478.jpg


PXL_20230329_011059894.jpg


PXL_20230329_010946349.jpg


Note the similarities
Screenshot_20230328-190154.png


Screenshot_20230328-190354.png




FYI

The adjustment in the vac canisters that can not be opened. Only sets the vacume at which the can starts moving. The same as adding washers.

The spring rate stays the same.

Screenshot_20230328-192341.png
 
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Ok, thanks for the education on this. I got the car back and it is running better, but they disconnected the vac advance completely. If it ever stops raining I will see what I can do with it.
 
These are the same for both 66 & 67
2642242/IBS-4013A - Complete
2642461/IBS-4013AS - Partial (less cap/rotor)

2642358/IBS4013B - CAP -Complete
2642405/IBS-4013BS - CAP -Partial (less cap/rotor)

65
2444853/IBS-4013 - Complete
2444873/IBS-4013S - Partial (less cap/rotor)


Alan
 
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#37 – At least Alan explained the redundant part number issue. To me it seems totally weird that they would put a different part number tag SCREWED to the BODY of the distributor just because they wanted to stock a replacement WITHOUT rotor and cap (how would the guys who assembled it know whether they were selling it with a cap on it or not?). I mean, every distributor actually installed on the production line had a rotor and cap, obviously.
 
mvh said:
To me it seems totally weird that they would put a different part number tag SCREWED to the BODY of the distributor just because they wanted to stock a replacement WITHOUT rotor and cap (how would the guys who assembled it know whether they were selling it with a cap on it or not?). I mean, every distributor actually installed on the production line had a rotor and cap, obviously
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I agree, they did some odd things like the part number cast into a part not being the part number in the parts book.

I think on the assy line the parts would have had codes etc.

In the parts department...

You could order a replacement dist or a dist ready to run.

There are a few other parts that are like that, I think the alternator could be ordered with or without a pulley (IIRC)
 
mvh said:
Yes, I just checked the 1966 FSM, and the specs are identical between it and the 2642242 which is what is listed for 1967 (and is in my 67 FB). But the # is listed for 1966.

So, why the different part number, is my question? Whatever...
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In 1966, the 2642461 is for the distributor without the cap and rotor, whereas the 2642242 is complete with the cap and rotor. Sounds like it's a replacement.
 
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