Phasing

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CRUZE 418

CRUZE 418

FABO Gold Member
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Well, not being an electrical guy, I am confused.
I watched the MSD video on phasing, thought that I now understood it. Asked another member if I could do it to a Mopar dist and he told me what to do. Just to double check, because I have an FBO ign module set up, I called FBO to ask . The woman didn't know what I was talking about, said she would get back with me.
Today she called back and said that what I was looking at through the hole that I had drilled in an old cap was my vac advance. I didn't know what else to say and said ok and humg up.
So, now I am confused about phasing.
 
Here is what rotor phasing "is." Whether breaker points, magnetic, whatever, "there is" a trigger that causes the spark to happen. You want this spark to happen when the rotor is aligned with the appropriate tower contact in the cap. If the rotor contact is "between" two cap towers, crossfire, and cap "carbon tracking" will happen.

In a "normal" distributor with mechanical advance, the rotor and mechanical advance move together. So if the rotor is properly phased at one point, movement of the advance mechanism will not change the alignment

But VACUUM advance moves the trigger (or points) in rotational degrees "or time" and changes the rotor phasing. The rotor alignment must have enough overlap in alignment so that the change with vacuum does not get the rotor "far off" the contact. In a perfect world, the rotor would be exactly centered when the vacuum advance is at the midpoint of it's movement

Of course most of us do not have "adjustable rotors" but this still illustrates

 
The same thing happens if you have a crank triggered ignition, but are using a distributor instead of coil-on-plug. The dist. must be aligned so that when the crank trigger fires, the rotor is "in range." When using a crank trigger, the spark is electronically moved by whatever controller, ignition, or EFI you are using. In that case, the rotor gets towards "out of phase" at each end of the advance curve, and since there is no mechanical advance (locked distributor) the alignment must be checked carefully. Over the years some weird rotors have been used to assure alignment, such as 4 whangers and 6 bangors

Like this

220048d1384472953-reading-dist-cap-rotor-distributor-cap-rotor-002.jpg


Below, there are some wider than this, I cannot find what I was looking for. This is for an early GM 225 V6

rotor.png
 
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I drilled a hole in an old cap, and when looking through that hole, it appears to me that the spark is to the right of the dist stud and going back to the left to make the arc.
Do not remember if I had the vac advance disconnected, I can go back out and switch caps and wiring and warm the engine up.for a refresher on what I saw.
 
In the MSD video, the rotor was slotted, easy to adj. Not so with a Mopar electronic dist.
 
You need to tell us more about what you have and what you are doing. If this is a Mopar breakerless distributor you may have the reluctor installed wrong, or the wires need reversed on the pickup.
 
Reluctor is on correctly, SB, clockwise rotation. Wouldn't it be difficult to get the wiring crossed? Everything is plug and play stock wiring. The only thing different in the wiring is that I have the square back alt harness and 4 terminal ballast. The FBO module by passes the ballast. This square back alt harness is a plug and play harness for mopar electronic ignition. My Dart is a '69. I would send pictures, but I can no longer send any pictures on this site, not even pictures that I have sent before. Email and message yes, FABO, no.
 
On an OEM electronic mopar you can change the rotor phasing with an easy mod. Remove the roll pin that sets the reluctor position. Drill and tap the side of the reluctor to 6/32 and install a set screw. The reluctor fires on the trailing edge.
 
#9. I am sorry, but that is probably a little out of my wheelhouse. Probably because I am not confident that I can understand and then do the task.
 
mderoy340 said:
On an OEM electronic mopar you can change the rotor phasing with an easy mod. Remove the roll pin that sets the reluctor position. Drill and tap the side of the reluctor to 6/32 and install a set screw. The reluctor fires on the trailing edge.
Click to expand...

Jeez ! I never thought of that ! Great idea.
 
CRUZE 418 said:
Reluctor is on correctly, SB, clockwise rotation. Wouldn't it be difficult to get the wiring crossed? Everything is plug and play stock wiring. The only thing different in the wiring is that I have the square back alt harness and 4 terminal ballast. The FBO module by passes the ballast. This square back alt harness is a plug and play harness for mopar electronic ignition. My Dart is a '69. I would send pictures, but I can no longer send any pictures on this site, not even pictures that I have sent before. Email and message yes, FABO, no.
Click to expand...

I cannot prove this but "it seems" from posts on here that a few pickup coils were reversed polarity. So even though they are "plug" connected, they may be wrong.

I'm also not sure about dist. parts interchange. If you have a dist that is not known to be factory original, it might have some mis-matched parts somehow.
 
I hate to sound like a broken record but what problem are you trying to solve?
 
CRUZE 418 said:
I tried to explain in post #5.
Click to expand...
Just how far away are they? If they don't get further than "corner to corner" and the vacuum advance movement sweeps the rotor past the contact, then you are OK.

This diagram shows the practical limits

oops lol

phasing.jpg
 
Okay, got the diagram. I am outta time tonight to recheck this, driving up to Minnesota for the Stillwater Mopar Event tomorrow. I will recheck this sometime Sunday afternoon or Monday. Will get back with you.
Thank you again for the info!
 
I don't remember but it seems the back of my mind that not all vac cans are created equal. I don't know if "breaker points" vac cans are same as breakerless or not Keep that in mind
 
Mine is the dist that you can stick an allen
Wrench into the vac can and adj. Which I did adj per FBO's instructions. I also have their limiter plate installed at 34°.
The terminals inside of my dist cap have a thin electrical strike on the left side and that strike grows into a huge splotch on the right side, another reason why I believe my phasing may be off. When I recheck on Sunday, not sure that I will have a definitive answer as to how much it is or isn't to the right of the terminal. Till then.
 
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