hmartin025 wrote:

  .......then removed cap and discovered rotor was almost 3/4 inch away from mark on dist. "There's phasing"....

Yep, hm, and as you discovered, no adjustment of the timing or repositioning of the distributor gear on the cam gear corrected the situation.
 

Last edited by boomyal (9/20/2014 12:39 PM)

MarkinSC wrote:

I don't think thats phasing.   Yes the rotor is not "aligned" with the #1 cylinder thats ready to fire, but then again, i don't think thats phasing.    The rotor wanders a few degrees as it spins in the distributor.   It can wander a few degrees before the cap pole that is supposed to fire, and a few degrees after the cap pole that its supposed to fire, and the spark will still jump to that single proper cap pole.   But if the range of degrees it wanders is not correct, then the spark has the ability to jump to an adjacent cap pole or even two poles at once.

Assuming that howard removed the cap =  the engine was off when he check the rotors position,

Then I would wonder if just rotating the distributor, if possible,  until the #1 cap pole was hovering over the rotor,  or simply restabbing the distributor so that the rotor was aligned with the #! cap pole, would have solved his issue without having to reposition the mounting plate.

hello mark . . according to my understabding of websters definition of phasing that i posted you actually can call this phasing . . also as i mentioned back in  post 247 lol you  can make the rotor transfer spark closer or farther to a post by moving the rotor or reluctor or pick up but not by rotating the distributor while it is installed. . this goes for removing it to . . if you remove the dist and reposition it and set it to the same timing like 10 degrees btdc for example . it will still fire the same distance from a post . . . the only time it fires farther from a post is when the distributor vacuum can advances the pick up which is shown in the last video i posted . . . i s

Last edited by barnett468 (9/20/2014 5:45 PM)

MarkSC wrote:

"How many times have i read in this thread, that vacuum advance only affects TIMING and not PHASING?"

it affects timing and the following. you can call the affect what ever you like.

". the only time it fires farther from a post is when the distributor vacuum can advances the pick up which is shown in the last video i posted" 

   
 

My interpretation..... Think of it as lining up the timing marks on the timing chain,only with two timing chains,  when the magnetic pick-up and the reluctor are lined up the tip of the rotor is not lined up with the terminal in the distributor cap, any amount of rotation of the distributor will not align all of the timing marks because all timing marks turn together. at that point an internal adjustment has to be made to align one set of timing marks independant of the other set.

bulletbirdman wrote:

Okay, Ive read and here's my final interpretation: Incorrect Phasing is a problem associated with electronic ignition systems caused by mis-alignment  of the magnetic pick-up or sensing device in the distributor causing the firing signal to fire when the rotor and cap stud are to far apart. Rotating the distributor will also rotate the pick-up thus maintaining this mis-alignment. Fix: re-align the pickup or buy a magneto and forget about it.

****OR*****, I just recently saw a distributor that used an adjustable rotor.  It was a large diameter thing with two screws on top.  You loosened the screws, rotated the tip to where you wanted it, then tightened the screws back down.

I do not know the brand or what models they fit.
 

And also, the mecanical and vacuum advance DO affect phasing of a few degrees!
Howard

boomyal wrote:

hmartin025 wrote:

And also, the mecanical and vacuum advance DO affect phasing of a few degrees!
Howard

Well Howard, you may be right.  This would be good reason to set your phasing such that the rotor tip fires slightly after the cap post, at idle, so that as the 'advance' actuates' the fire point is pulled back across the cap contact and fires slightly before reaching the contact at maximum advance.

I will shortly be making a video of the circumstances.  It has now been a number of years since I had to re-phase my distributor, so I will re-aquaint myself with the particulars.

Still my recollection is that my rotor was firing half way to the next cylinder (at idle and leaving a big build up of resistance carbon on the cap distribution contact to rotor and leaving track marks around the inside wall of the cap AND running like crap) and no amount of increase in RPM and the resulting centrifugal advance brought the spark back near the #1 cylinder post.
 

Boomyal,  you have posted several times in this thread that vacuum advance does not affect phasing only timing,  now you are possibly open to the idea from Howard that it may affect phasing a few degrees? 

MarkinSC wrote:

Boomyal,  you have posted several times in this thread that vacuum advance does not affect phasing only timing,  now you are possibly open to the idea from Howard that it may affect phasing a few degrees? 

Mark, I am a humble guy. It has been a number of years since I went through this excercise in 'phasing'. It was as new a concept to me as it has been to others on this thread. I will revisit this situatation and either prove my contention or admit I was wrong.  That all being said, I am not far off the mark in my last statements in the post above. It is a real issue that affects more people than they realize.
 

Last edited by boomyal (9/21/2014 8:47 PM)

Greg B wrote:

I'm gathering that a phasing problem is basically a result of manufacturers tolerances.  

Actually, when it occurs, it is typically with aftermarket parts.
.
 

MarkinSC wrote:

boomyal wrote:

MarkinSC wrote:

Boomyal,  you have posted several times in this thread that vacuum advance does not affect phasing only timing,  now you are possibly open to the idea from Howard that it may affect phasing a few degrees? 

Mark, I am a humble guy. It has been a number of years since I went through this excercise in 'phasing'. It was as new a concept to me as it has been to others on this thread. I will revisit this situatation and either prove my contention or admit I was wrong.  That all being said, I am not far off the mark in my last statements in the post above. It is a real issue that affects more people than they realize.
 

Boomyal, if it was't for you I wouldn't have even HEARD of rotor phasing before. I'm glad you brought it to my attention. I'm glad to try to learn it.  But man, I  have been thru the ringer trying to understand it.   And when I thought I understood it, then the rug got pulled out from under me again. I have been getting a bit frustrated as to why I can't grasp this concept.  As fast I read everyones posts,  then i noticed that they have been "edited".  So I start to doubt what was originally posted and what is now posted.
 

Only one of my posts was "edited"/changed for the purpose of clarification. A couple might have had info added shortly after my orig post so as not to make a new post which would simply take up more space on the thread. Any others were for spelling or to capitolize etc..
.

Last edited by barnett468 (9/21/2014 9:43 PM)

hmartin025 wrote:

This is an excellent topic, and one that all should understand as we struggle to understand these infernal combustion engines. In the long run we all win!
Barnett, its my understanding the mechanical advance also contributes to phasing. Look at it this way, as the centrifical weights move and change the timing the cam rotates on the main distributor shaft which changes the amount of degrees inside the distributor as does the vacuum advance.
I'm sorry I'm not a wordsmith as I see many of you are. You state your thoughts so well! I struggle to explain mine. Hope this makes sense
Howard
 

Hello hmartin;

The entire engine may be easier to understand than a distributor, lol.
 
Please read my post again a few times and think about it. i know it can be tough to understand without visual aids but even better yet, do the following if you want.
 
Remove your distributor cap.
 
Rotate the rotor so you know the mechanical advance still works, lol.
 
Now, line the reluctor [if you have one] up with the pick up.
 
Put a felt tip line from the reluctor to the pick up. It can only fire when this or one of the other 7 reluctor tips line up with the felt mark on the pick up. It's simply not possible for it to do otherwise.
 
Now, with the reluctor and pick up still lined up, put a mark on the distributor housing exactly where the rotor is pointing.
 
Ok, now the reluctor tip is lined up with the pick up so the rotor will fire at this point in its rotation if the vacuum advance is disabled. There is no other option.
 
Now, simply rotate the rotor and look at the line on the reluctor and the pick up. You will clearly see that they no longer line up. This means that there will be no spark at this position.

Look at it this way, it will only fire when a reluctor tip is lined up with the pick up. it is simply impossible for it to do otherwise because there is no connection until this occurs.

Now, move your distributor housing or the rotor/reluctor or the pick up and you will see that without exception, it will only fire when a reloctor tip is lined up with the pick up.

All the mechanical advance unit does is move the rotor and reluctor farther ahead of the distributor shaft so it fires sooner in relation to the pistons location. It does not change the position of the pick up or the position of the rotor to the reluctor.
 
Mechanical advance unit photo.



.
 
 
 
 

 

MarkinSC wrote:

boomyal wrote:

MarkinSC wrote:

Boomyal,  you have posted several times in this thread that vacuum advance does not affect phasing only timing,  now you are possibly open to the idea from Howard that it may affect phasing a few degrees? 

Mark, I am a humble guy. It has been a number of years since I went through this excercise in 'phasing'. It was as new a concept to me as it has been to others on this thread. I will revisit this situatation and either prove my contention or admit I was wrong.  That all being said, I am not far off the mark in my last statements in the post above. It is a real issue that affects more people than they realize.
 

Boomyal, if it was't for you I wouldn't have even HEARD of rotor phasing before. I'm glad you brought it to my attention. I'm glad to try to learn it.  But man, I  have been thru the ringer trying to understand it.   And when I thought I understood it, then the rug got pulled out from under me again. I have been getting a bit frustrated as to why I can't grasp this concept.  As fast I read everyones posts,  then i noticed that they have been "edited".  So I start to doubt what was originally posted and what is now posted.
 

Mark, it's easy enough.  Get yourself an extra cap, a white paint pen and a timing light and try it yourself. Run the engine at different speeds and play with the timing and you can see for yourself.