FYI FORD MustangSteve's Ford Mustang Forum » Distributor rotor phasing

boomyal · 9/16/2014 10:14 PM

barnett468 wrote:
........actually, the more the plate advances", the earlier the spark is triggered in the rotors rotation............

You still do not get it yet, barnet. Either rotating the distributor OR rotating the point plate via the vacuum advance only triggers the spark earlier in relation to the position of the piston. It does not change the trigger point of the rotor in relation to a specific cylinder stud on the distributor cap.

This is where the problem lies. Regardless of your choice of advance or retard setting of the distributor, if the rotor does not fire adjacent to the cylinder lug on the cap, then you are out of phase and the charge (spark) does not know what path to take cause a degredation of the spark, at the plug.

The action of the point plate under the influence of the vacuum diaphram is the equivalant of momentarily rotating the whole distributor. This does not affect the point at which the rotor tip throws a charge at any given cylinder lug on the distributor cap. But then, I am repeating myself.

Ideally, at whatever setting of advance or retard, the rotor tip would make positive contact with the lug on the distributor cap before the coil would release it's charge. This of course is not possible as you would chew up all the pieces. This is why you want the charge released, at any timing setting, when the rotor tip is right next to the lug on the cap. Whew! I know it is a some what abstract concept because you are dealing with two different planes and it is, at first hand, difficult to reconcile the two.

Last edited by boomyal (9/16/2014 10:27 PM)

barnett468 · 9/16/2014 10:40 PM

boomyal wrote:
You still do not get it yet, barnet. Either rotating the distributor OR rotating the point plate via the vacuum advance only triggers the spark earlier in relation to the position of the piston.

Actually I DO get it and have known how this works for the last 42 years but I appreciate you trying to explain it to me. As I mentioned, it can be difficult to understand.

As I mentioned previously, rotating the plate causes the spark to fire at a different point in the distributor shafts rotation. it has no other choice.

Rotating the distributor does not change point at which the spark fires relative to the distributor shafts position, but, because the cap has been moved, the point at which the spark fires from the rotor to the post changes.

The more the more the timing is advanced by rotating the advance plate, the earlier the spark fires in the distributor shafts rotation.

The more one retards it by rotating the advance plate, the later the spark will fire in the distributors shaft rotation. It has always been this way and most likely always will.

If one is using aftermarket parts especially with high energy ignitions and the spark is jumping between two posts then clocking the rotor closer to the required post will reduce the possibility of this occuring but it will not change the timing.

This spark jumping condition does not exist on stock systems using near stock timing specs.

the more energy the system has, the farther a spark will jump. if one has a std size dist cap and the spark is jumping between two posts then instead of repositioning the rotor closer to the desired post, one can use a larger diameter cap because it spaces the posts farther apart which reduces the potential for the spark to bounce between two different posts.

you can even do some tests to show yourself exactly how this works.

Anyway, I actually DO get it and have known how this works for the last 42 years. I was simply trying to answer the questions but as I said, it can be difficult to understand.
.
.

Last edited by barnett468 (9/17/2014 4:48 AM)

MarkinSC · 9/17/2014 4:45 AM

barnett468 wrote:
MarkinSC wrote:
if the arm was too short, then it would have been pullng the plate counter clockwise, regardless if any vacuum was present.
no, actually it would have been pulling it clockwise in a v8 engine. the dist shaft moves counter clockwise, therefore, the plate must rotate clockwise to increase/advance timing.
.
http://t1.gstatic.com/images?q=tbn:ANd9GcRkbwDq-r9p-jrUDyZJLy7VWWkoMOsIBYeC--40_cF7j7AozdyHF981RwJ6
.

my point is that if the arm is too short, its pulling on the plate when it shouldn't be, and its advancing the timing as it would for an off idle condition when in actuality the engine is at idle and should not have any vacuum and should not have any advance.

barnett468 · 9/17/2014 4:56 AM

MarkinSC wrote:
barnett468 wrote:
MarkinSC wrote:
if the arm was too short, then it would have been pullng the plate counter clockwise, regardless if any vacuum was present.
no, actually it would have been pulling it clockwise in a v8 engine. the dist shaft moves counter clockwise, therefore, the plate must rotate clockwise to increase/advance timing.
.
http://t1.gstatic.com/images?q=tbn:ANd9GcRkbwDq-r9p-jrUDyZJLy7VWWkoMOsIBYeC--40_cF7j7AozdyHF981RwJ6
.
my point is that if the arm is too short, its pulling on the plate when it shouldn't be, and its advancing the timing as it would for an off idle condition when in actuality the engine is at idle and should not have any vacuum and should not have any advance.

It's probably just a difference in terminology.

The vacuum advance can does not actually "pull" or "push" on anything when there is no vavuum to it.

A shorter arm simply repositions the pick up or points so they fire sooner. A longer arm does the opposite.

if the pick up or points are advanced or retarded fsar enough, it is possible that it fires with the rotor close enough to the center between two terminals that it can fire to either or both simultaneously which will cause a problem.
..

Last edited by barnett468 (9/17/2014 5:04 AM)

MarkinSC · 9/17/2014 4:56 AM

boomyal wrote:
barnett468 wrote:
........actually, the more the plate advances", the earlier the spark is triggered in the rotors rotation............
You still do not get it yet, barnet. Either rotating the distributor OR rotating the point plate via the vacuum advance only triggers the spark earlier in relation to the position of the piston. It does not change the trigger point of the rotor in relation to a specific cylinder stud on the distributor cap.

This is where the problem lies. Regardless of your choice of advance or retard setting of the distributor, if the rotor does not fire adjacent to the cylinder lug on the cap, then you are out of phase and the charge (spark) does not know what path to take cause a degredation of the spark, at the plug.

The action of the point plate under the influence of the vacuum diaphram is the equivalant of momentarily rotating the whole distributor. This does not affect the point at which the rotor tip throws a charge at any given cylinder lug on the distributor cap. But then, I am repeating myself.

Ideally, at whatever setting of advance or retard, the rotor tip would make positive contact with the lug on the distributor cap before the coil would release it's charge. This of course is not possible as you would chew up all the pieces. This is why you want the charge released, at any timing setting, when the rotor tip is right next to the lug on the cap. Whew! I know it is a some what abstract concept because you are dealing with two different planes and it is, at first hand, difficult to reconcile the two.

Twisting the distributor, in actuality permanently moves and creates a baseline resting point for the breaker plate. Vacuum advance temporarily moves the breaker plate when under load, advancing the spark and at the same time changing the relation between the rotor and the cap poles.

If the distributor moves, then the cap HAS TO MOVE TOO, they are connected. Right? But moving the distributor does NOT move the rotor. The shaft is independent of the distributor and is rotated with the camshaft. So while it does advance the spark in relation pistion degrees, it also changes the relation of the cap pole and the rotor. And if what you say phasing is, "the rotor not being lined up with a cap pole", then timing changes the rotors position, which essentially means, timing does change the rotors "phasing".

barnett468 · 9/17/2014 5:23 AM

.
Twisting the distributor, in actuality permanently moves and creates a baseline resting point for the breaker plate. If the distributor moves, then the cap HAS TO MOVE TOO, they are connected. Right?

Moving the dist housing moves the housing, the cap and pick up or points equal amounts.

Vacuum advance temporarily moves the breaker plate when under load,

No, the vac adv is mainly functional at steady throttle and deceleration. It is disabled when one floors the gas. the main purpose is to increase mileage which in turn reduces the amount of polution per mile the engine procuces...

advancing the spark and at the same time changing the relation between the rotor and the cap poles.

Please see my previous post

But moving the distributor does NOT move the rotor.

correct

The shaft is independent of the distributor and is rotated with the camshaft.

Correct

So while it does advance the spark in relation pistion degrees,

Correct

it also changes the relation of the cap pole and the rotor.

Moving the dist housing does, moving the advance plate does not.

And if what you say phasing is, "the rotor not being lined up with a cap pole",

That is not what I said. please see my previous post to mustang steve.

then timing changes the rotors position,

the mechanical advance unit changes the actual position of the rotor.

which essentially means, timing does change the rotors "phasing".

Please see previous post.

.

Last edited by barnett468 (9/17/2014 5:29 AM)

wsinsle · 9/17/2014 6:28 AM

Boom going back to the original discussion, this is just a simple diagram I drew up to see if I'm understanding this correctly. Does this diagram make sense?

Mach1_Ron · 9/17/2014 7:35 AM

And this is the Very reason I run a Completely Mechanical Distributor...well that and the fact I only pull about 7 inches of vacuum... lol

MarkinSC · 9/17/2014 7:38 AM

barnett468 wrote:
.
Twisting the distributor, in actuality permanently moves and creates a baseline resting point for the breaker plate. If the distributor moves, then the cap HAS TO MOVE TOO, they are connected. Right?

Moving the dist housing moves the housing, the cap and pick up or points equal amounts.

Vacuum advance temporarily moves the breaker plate when under load,

No, the vac adv is mainly functional at steady throttle and deceleration. It is disabled when one floors the gas. the main purpose is to increase mileage which in turn reduces the amount of polution per mile the engine procuces...

advancing the spark and at the same time changing the relation between the rotor and the cap poles.

Please see my previous post

But moving the distributor does NOT move the rotor.

correct

The shaft is independent of the distributor and is rotated with the camshaft.

Correct

So while it does advance the spark in relation pistion degrees,

Correct

it also changes the relation of the cap pole and the rotor.

Moving the dist housing does, moving the advance plate does not.

And if what you say phasing is, "the rotor not being lined up with a cap pole",

That is not what I said. please see my previous post to mustang steve.

then timing changes the rotors position,

the mechanical advance unit changes the actual position of the rotor.

which essentially means, timing does change the rotors "phasing".

Please see previous post.

.

OK I think the light bulb is going on now. Let me see if I got this straight.

I am looking at a distributor that is in my lap, from a 1950 ford, V8, vacuum advance only. The stator has an arrow stamped on it that shows that it turns CLOCKWISE. Even if I doubted myself on which direction it turns, I have the diagram for the ignition, and it shows the firing order, with an arrow showing direction in which it turns.

We established the following facts:
             that the shaft inside the distributor is independent from the distributor housing,
            the stator is part of the shaft,
             the rotor sits on top of the stator
             it turns Clockwise by the camshaft
             physically turning the distributor/cap, also phsyically turns the breaker plate, which affects TIMING  but since the rotor doesn't turn with the distributor it also affects PHASING ( rotors location unde the cap pole)

Two things happen here:
            Turning the distributor /cap will move the cap pole either closer or away from the rotor. (Phasing)
             Turning the distributor / cap will also move the breaker plate with the points / pickup  mating point on the stator / Reluctor.  (Timing)

Vacuum advance, when applied, temporarily moves the breaker plate Counter Clockwise, using vacuum to advance the spark, but only moves the breaker plate with the points /pickup, and does NOT affect the rotors position under a cap pole. Anything that changes the contact point where the points hit the stator affects timing. Vacuum advance affects TIMING only, and not PHASING.

Initial Base timing, which is set by physically turning the distributor / housing Affects both TIMING and PHASING.

Vacuum advance, usually is not being applied at idle, but is applied under part throttle and deceleration so it should only affect TIMING during those times. BUT, when vacuum advance IS incorrectly being applied at idle ( as would happen with weak or missing springs or incorrect arm length), it will affect the base timing at idle, which may cause a person to inadvertently retard the timing by physically turning the distributor /cap which will change the cap pole and rotors position with each other, which in affect WILL affect PHASING. Which was happening to Bobn?

Do I got it right now???

GEEZ

fgsjeff · 9/17/2014 7:50 AM

Ok, here is my take on this. Timing determines when the spark is delivered to the plug. Phasing determines how much "fire" gets to the plug. If it is out on timing, it may spark early or late, but if it is out on phasing it may spark on time but with diminished "spark". If the rotor doesn't line of correctly with the cap pole, say it is off a little, it wont deliver as much spark. If it is too far off, it may deliver spark to the wrong plug, or even two plugs. The whole rotor is a "system", if you rotate the rotor, it doesn't chage the "system", it just changes the "timing". However if you open the "system", there is another "Internal system" inside, Phasing the "internal system" to where the rotor properly aligns with the cap will give you a hotter spark.

Correct?

Last edited by fgsjeff (9/17/2014 7:53 AM)

barnett468 · 9/17/2014 1:07 PM

MarkinSC wrote:
barnett468 wrote:
.
Twisting the distributor, in actuality permanently moves and creates a baseline resting point for the breaker plate. If the distributor moves, then the cap HAS TO MOVE TOO, they are connected. Right?

Moving the dist housing moves the housing, the cap and pick up or points equal amounts.

Vacuum advance temporarily moves the breaker plate when under load,

No, the vac adv is mainly functional at steady throttle and deceleration. It is disabled when one floors the gas. the main purpose is to increase mileage which in turn reduces the amount of polution per mile the engine procuces...

advancing the spark and at the same time changing the relation between the rotor and the cap poles.

Please see my previous post

But moving the distributor does NOT move the rotor.

correct

The shaft is independent of the distributor and is rotated with the camshaft.

Correct

So while it does advance the spark in relation pistion degrees,

Correct

it also changes the relation of the cap pole and the rotor.

Moving the dist housing does, moving the advance plate does not.

And if what you say phasing is, "the rotor not being lined up with a cap pole",

That is not what I said. please see my previous post to mustang steve.

then timing changes the rotors position,

the mechanical advance unit changes the actual position of the rotor.

which essentially means, timing does change the rotors "phasing".

Please see previous post.

.
OK I think the light bulb is going on now. Let me see if I got this straight.

I am looking at a distributor that is in my lap, from a 1950 ford, V8, vacuum advance only. The stator has an arrow stamped on it that shows that it turns CLOCKWISE. Even if I doubted myself on which direction it turns, I have the diagram for the ignition, and it shows the firing order, with an arrow showing direction in which it turns.

We established the following facts:
that the shaft inside the distributor is independent from the distributor housing,
the stator is part of the shaft,
the rotor sits on top of the stator
it turns Clockwise by the camshaft
physically turning the distributor/cap, also phsyically turns the breaker plate, which affects TIMING but since the rotor doesn't turn with the distributor it also affects PHASING ( rotors location unde the cap pole)

Two things happen here:
Turning the distributor /cap will move the cap pole either closer or away from the rotor. (Phasing)
Turning the distributor / cap will also move the breaker plate with the points / pickup mating point on the stator / Reluctor. (Timing)

Vacuum advance, when applied, temporarily moves the breaker plate Counter Clockwise, using vacuum to advance the spark, but only moves the breaker plate with the points /pickup, and does NOT affect the rotors position under a cap pole. Anything that changes the contact point where the points hit the stator affects timing. Vacuum advance affects TIMING only, and not PHASING.

Initial Base timing, which is set by physically turning the distributor / housing Affects both TIMING and PHASING.

Vacuum advance, usually is not being applied at idle, but is applied under part throttle and deceleration so it should only affect TIMING during those times. BUT, when vacuum advance IS incorrectly being applied at idle ( as would happen with weak or missing springs or incorrect arm length), it will affect the base timing at idle, which may cause a person to inadvertently retard the timing by physically turning the distributor /cap which will change the cap pole and rotors position with each other, which in affect WILL affect PHASING. Which was happening to Bobn?

Do I got it right now???

GEEZ

omg . . you have a load o matic distributor so you can not play . . in your case the more load you have the more advance you have otherwise in general what you said is correct . . if you use that dist in the proper eng i can help you set it up if needed . . it is a horrible system . . . . or ok yes

barnett468 · 9/17/2014 1:25 PM

fgsjeff wrote:
Ok, here is my take on this. Timing determines when the spark is delivered to the plug. . yes . . . Phasing determines how much "fire" gets to the plug. . no . .. . If it is out on timing, it may spark early or late, . yes . . . but if it is out on phasing it may spark on time but with diminished "spark". . nnot really . . . If the rotor doesn't line of correctly with the cap pole, say it is off a little, it wont deliver as much spark. . that is not the prob with incorrect phasing . . . . If it is too far off, it may deliver spark to the wrong plug, or even two plugs. . thats it . . . The whole rotor is a "system", . yes shaft rotor reluctor or points cam and mechanical advance unit . . . if you rotate the rotor, it doesn't chage the "system", . no but inertia from acceleration causes the rotor to move opposite of its direction of rotation . further clockwise if it normally rotatees counter clockwise or it advance s. . . it just changes the "timing". . . However if you open the "system", there is another "Internal system" inside, sorry not sure what you mean too vague . . . Phasing the "internal system" to where the rotor properly aligns with the cap will give you a hotter spark.
this can be done by repositioninng the rotor or reluctor or pick up.
Correct?

b

Last edited by barnett468 (9/17/2014 1:38 PM)

MarkinSC · 9/17/2014 1:45 PM

barnett468 wrote:
MarkinSC wrote:
barnett468 wrote:
.
Twisting the distributor, in actuality permanently moves and creates a baseline resting point for the breaker plate. If the distributor moves, then the cap HAS TO MOVE TOO, they are connected. Right?

Moving the dist housing moves the housing, the cap and pick up or points equal amounts.

Vacuum advance temporarily moves the breaker plate when under load,

No, the vac adv is mainly functional at steady throttle and deceleration. It is disabled when one floors the gas. the main purpose is to increase mileage which in turn reduces the amount of polution per mile the engine procuces...

advancing the spark and at the same time changing the relation between the rotor and the cap poles.

Please see my previous post

But moving the distributor does NOT move the rotor.

correct

The shaft is independent of the distributor and is rotated with the camshaft.

Correct

So while it does advance the spark in relation pistion degrees,

Correct

it also changes the relation of the cap pole and the rotor.

Moving the dist housing does, moving the advance plate does not.

And if what you say phasing is, "the rotor not being lined up with a cap pole",

That is not what I said. please see my previous post to mustang steve.

then timing changes the rotors position,

the mechanical advance unit changes the actual position of the rotor.

which essentially means, timing does change the rotors "phasing".

Please see previous post.

.
OK I think the light bulb is going on now. Let me see if I got this straight.

I am looking at a distributor that is in my lap, from a 1950 ford, V8, vacuum advance only. The stator has an arrow stamped on it that shows that it turns CLOCKWISE. Even if I doubted myself on which direction it turns, I have the diagram for the ignition, and it shows the firing order, with an arrow showing direction in which it turns.

We established the following facts:
that the shaft inside the distributor is independent from the distributor housing,
the stator is part of the shaft,
the rotor sits on top of the stator
it turns Clockwise by the camshaft
physically turning the distributor/cap, also phsyically turns the breaker plate, which affects TIMING but since the rotor doesn't turn with the distributor it also affects PHASING ( rotors location unde the cap pole)

Two things happen here:
Turning the distributor /cap will move the cap pole either closer or away from the rotor. (Phasing)
Turning the distributor / cap will also move the breaker plate with the points / pickup mating point on the stator / Reluctor. (Timing)

Vacuum advance, when applied, temporarily moves the breaker plate Counter Clockwise, using vacuum to advance the spark, but only moves the breaker plate with the points /pickup, and does NOT affect the rotors position under a cap pole. Anything that changes the contact point where the points hit the stator affects timing. Vacuum advance affects TIMING only, and not PHASING.

Initial Base timing, which is set by physically turning the distributor / housing Affects both TIMING and PHASING.

Vacuum advance, usually is not being applied at idle, but is applied under part throttle and deceleration so it should only affect TIMING during those times. BUT, when vacuum advance IS incorrectly being applied at idle ( as would happen with weak or missing springs or incorrect arm length), it will affect the base timing at idle, which may cause a person to inadvertently retard the timing by physically turning the distributor /cap which will change the cap pole and rotors position with each other, which in affect WILL affect PHASING. Which was happening to Bobn?

Do I got it right now???

GEEZ
omg . . you have a load o matic distributor so you can not play . . in your case the more load you have the more advance you have otherwise in general what you said is correct . . if you use that dist in the proper eng i can help you set it up if needed . . it is a horrible system . . . . or ok yes

LOL Yes its a load a matic distributor. Its all I had around right now. I have a flathead engine that it needs to go into. I got alot to do before I can get to that point though.

barnett468 · 9/17/2014 2:04 PM

yeah ok lol . . in case you dont know that fine unit gets vacuum from the carb and intake manifold which is controlled by mr spark control valve . . do yourself and buy an old mallory centrifugal dist off ebay lol.

MarkinSC · 9/17/2014 2:16 PM

barnett468 wrote:
yeah ok lol . . in case you dont know that fine unit gets vacuum from the carb and intake manifold which is controlled by mr spark control valve . . do yourself and buy an old mallory centrifugal dist off ebay lol.

It only has 1 vacuum port. line went to the carb. I dont see any other vacuum ports on it. An old mallory centrifugal distributor? Ok I will search for that.

Greg B · 9/17/2014 2:17 PM

reading all this made my head dizzy.

HenryJ · 9/17/2014 3:07 PM

Greg B wrote:
reading all this made my head dizzy.

I see what you did there. Your head is just out of phase.

MachTJ · 9/17/2014 5:11 PM

The moral of the story is that you want the spark to travel from the rotor to the cap in the closest position possible. Since spark has the ability to jump gaps, it will be more intense or powerful the less distance it has to jump. Thats why the guy changed the rotor position in the msd video. It boils down to tuning the parts in the distributor to have the coil fire when the rotor is right at the cap stud and not 1/8" away. The MSD video is kind of misleading in that its not a constant stream of electricity always shooting from the coil, its a pulse, and you want that pulse to happen when the two points are close together and not far apart. As the gentleman in the video explained, it looks like roughly the width of the rotor tip was about 20 degrees of rotation.

If I am correct phasing fixes pickup position relative to distributor housing position and or distributor cap location relative to distributor housing location. Say if the small locating tab or nothch in the cap is molded a couple degrees out of position. Couple of ways it can be remedied, moving the pickup or points or with an adjustable rotor. I think I got it.

Last edited by MachTJ (9/17/2014 5:28 PM)

boomyal · 9/17/2014 5:14 PM

Greg B wrote:
reading all this made my head dizzy.

Yep, it did mine too! You just have to look at the issue in two different planes. One is when the distributor fires in relation to the position of the piston, ie BTDC, TDC, ATDC. This is dependent on the rotational position of the distributor (including any advance/retard of the point/ignitor plate) to the position of all the valves and pistons.

The other is when the system fires in relation to the proximity of the rotor tip to the cylinder cap lug in the distributor cap. Whatever your choice of timing (or the distributors choice of vacuum or centrifugal advance), the rotor tip needs to be adjacent to the cylinder lug of the cap for the cylinder that it wants to fire. That is phasing.

Never the twain shall meet!

Last edited by boomyal (9/17/2014 5:17 PM)

MarkinSC · 9/17/2014 5:27 PM

Greg B wrote:
reading all this made my head dizzy.

Sorry for that, my bad. Sorry also for hijacking this thread. Also, my bad.

But really, was I the only one that had a hard time grasping this concept?? LOL

barnett468 · 9/17/2014 5:39 PM

MarkinSC wrote:
barnett468 wrote:
yeah ok lol . . in case you dont know that fine unit gets vacuum from the carb and intake manifold which is controlled by mr spark control valve . . do yourself and buy an old mallory centrifugal dist off ebay lol.
It only has 1 vacuum port. line went to the carb. I dont see any other vacuum ports on it. An old mallory centrifugal distributor? Ok I will search for that.

that is correct however it gets the manifollf vac thru the carb also the thing on the outside of the carb that looks like a power vallve determines where the vac comes from .. itstotally fd up lol.

barnett468 · 9/17/2014 5:46 PM

MachTJ wrote:
The moral of the story is that you want the spark to travel from the rotor to the cap in the closest position possible. Since spark has the ability to jump gaps, it will be more intense or powerful the less distance it has to jump. Thats why the guy changed the rotor position in the msd video. It boils down to tuning the parts in the distributor to have the coil fire when the rotor is right at the cap stud and not 1/8" away. The MSD video is kind of misleading in that its not a constant stream of electricity always shooting from the coil, its a pulse, and you want that pulse to happen when the two points are close together and not far apart. As the gentleman in the video explained, it looks like roughly the width of the rotor tip was about 20 degrees of rotation.

If I am correct phasing fixes pickup position relative to distributor housing position and or distributor cap location relative to distributor housing location. Say if the small locating tab or nothch in the cap is molded a couple degrees out of position. Couple of ways it can be remedied, moving the pickup or points or with an adjustable rotor. I think I got it.

fn a yes xlnt addition . . with vacuum advance you want it to fire just before the rotor passes the post beecause as the advances is activated, it fires sooner in the rotors rotation so by the time you are at maybe 15 degrees additional advance the spark will fire before the rotor reaches the post . . .

Last edited by barnett468 (9/17/2014 7:35 PM)

barnett468 · 9/17/2014 5:54 PM

MarkinSC wrote:
Greg B wrote:
reading all this made my head dizzy.
Sorry for that, my bad. Sorry also for hijacking this thread. Also, my bad.

But really, was I the only one that had a hard time grasping this concept?? LOL

ummm . . my guess is . . no lol . . the video is visually helpful but grossly lacking in detailed explanation . . a better explanation would help greatly . . its one of those things that can be hard to explain and understand but once you understand it you think wow thats a simple concept lol.

Last edited by barnett468 (9/17/2014 5:59 PM)

MarkinSC · 9/17/2014 6:11 PM

barnett468 wrote:
MarkinSC wrote:
barnett468 wrote:
yeah ok lol . . in case you dont know that fine unit gets vacuum from the carb and intake manifold which is controlled by mr spark control valve . . do yourself and buy an old mallory centrifugal dist off ebay lol.
It only has 1 vacuum port. line went to the carb. I dont see any other vacuum ports on it. An old mallory centrifugal distributor? Ok I will search for that.
that is correct however it gets the manifollf vac thru the carb also the thing on the outside of the carb that looks like a power vallve determines where the vac comes from .. itstotally fd up lol.

i don't see that power valve thing, it has dual ford 94 carbs on a fenton intake.

boomyal · 9/17/2014 6:24 PM

barnett468 wrote:
....... beecause as the advances are activated it fires sooner in the rotors rotation so by the time you are at 40 degrees the spark will fire before the rotor reaches the post . . .

Incorrect, barnett. Whatever the phasing of the distributor, as the vacuum or centrifugal advance actuates, the rotor will still fire in the same spot relative to the distributor cap post. There would be no gain ( and plenty of loss) to be had to have the advance mechanism cause the rotor to fire farther and farther before (or after) it approaches the cap post,

There is plenty of gain to be had in making the rotor fire right at the cap lug, but earlier in the pistons upward travel as the engine's RPM increases.

Last edited by boomyal (9/17/2014 6:29 PM)

Index » FYI Ford, Classic Mustang Tech Discussion » Distributor rotor phasing

Re: Distributor rotor phasing

barnett468 wrote:

Re: Distributor rotor phasing

boomyal wrote:

Re: Distributor rotor phasing

barnett468 wrote:

MarkinSC wrote:

Re: Distributor rotor phasing

MarkinSC wrote:

barnett468 wrote:

MarkinSC wrote:

Re: Distributor rotor phasing

boomyal wrote:

barnett468 wrote:

Re: Distributor rotor phasing

Re: Distributor rotor phasing

Re: Distributor rotor phasing

Re: Distributor rotor phasing

barnett468 wrote:

Re: Distributor rotor phasing

Re: Distributor rotor phasing

MarkinSC wrote:

barnett468 wrote:

Re: Distributor rotor phasing

fgsjeff wrote:

Re: Distributor rotor phasing

barnett468 wrote:

MarkinSC wrote:

barnett468 wrote:

Re: Distributor rotor phasing

Re: Distributor rotor phasing

barnett468 wrote:

Re: Distributor rotor phasing

Re: Distributor rotor phasing

Greg B wrote:

Re: Distributor rotor phasing

Re: Distributor rotor phasing

Greg B wrote:

Re: Distributor rotor phasing

Greg B wrote:

Re: Distributor rotor phasing

MarkinSC wrote:

barnett468 wrote:

Re: Distributor rotor phasing

MachTJ wrote:

Re: Distributor rotor phasing

MarkinSC wrote:

Greg B wrote:

Re: Distributor rotor phasing

barnett468 wrote:

MarkinSC wrote:

barnett468 wrote:

Re: Distributor rotor phasing

barnett468 wrote:

Index » FYI Ford, Classic Mustang Tech Discussion » Distributor rotor phasing

Board footera

Index
» FYI Ford, Classic Mustang Tech Discussion
» Distributor rotor phasing

Index
» FYI Ford, Classic Mustang Tech Discussion
» Distributor rotor phasing