I think I'm back to my original position (I'm worse than a politician!!!), but I'll paypal everyone anyway because this is entertaining and got everybody to think. Especially Mike since he mailed out a distributor and Trendz who is going to test it and put it on youtube.

http://www.powerperformancenews.com/tech...configurations/

my eyes hurt so bad i'm ready to send everyone $10 .........

That confirms the rotor advances with both mech and vac advance. Robert has been clear in saying the rotor does not move forward with anything but vac advance.

Correct Sir, My statement/position is: "that mechanical adv will not alter rotor phasing" and that RP positioning is the relationship/clocking/distance between the rotor tip and the cap terminal when it fires which is checked by drilling the hole in the cap top and shining your timing light onto it just like you do down below on the dampener to check timing. My position: from idle to any RPM it will NOT move. I've observed it at least a dozen times in my work & again 2 days ago when I went out to my DD 85 Ramcharger & did it again & that dist has tight springs but I revved it up high enough so that I knew I was into some mech adv not sure how much & it did not budge. it shook a very slight bit cuz the bushings ain't dead on concentric but a moot point. Gentlemen place your bets (& actually that is just an expression as I'm sure online gambling is frowned upon) so we'll say that this is higher edumacation (Moparts Style) and the only question to be answered (which Trendz will likely answer for us next week (bless his heart) is WHO is the teacher and WHO is the student. Stay tuned for further episodes. RR. I want that steak! EDIT In the powerperformancenews video quoted above they state: "mechanical advance moves not only the position of the reluctor in relation to the pickup but also the rotor in relation to the distributor cap spark plug wire terminal" then (2) paragraphs down it says: "stock distributors align the rotor with the spark plug terminal on the distributor cap with the engine at the initial timing position and since the reluctor and the rotor are fixed together mechanical advance does not cause phasing issues because as the trigger is advanced so is the rotor". first statement is wrong and the second statement is correct. Trendz please hurry!

O.K. The distributor arrived this morning. The distributor machine is at work, so I won't be able to do it until Monday. Monday evening I will have the video results. Sorry, that's as soon as I can do it.
Mike, I'll send it back to you when I'm done. I haven't used distributors since the early '90s!

Trendz try this, the procedure I mentioned earlier (dist in a vise or in your hand) & see what you see. It'll take you 3 minutes if that. EDIT (1) hold dist housing in left hand with magnet at 12 o'clock (2) turn lower shaft so a tooth is lined up with the magnet (both at 12 o'clock) (3) note position of upper shaft notch which opposite to that is rotor location (RP) (4) turn lower shaft CCW (to the left) slightly (5) with the housing still being held so magnet is at 12 o'clock, grab lower shaft & hold it in this new position (with the tooth a bit to the left), & hold both solid with your left hand (6) with housing and lower shaft being held solid, grab the reluctor & twist it CW till the tooth is back lined up at 12 o'clock with the magnet which the magnet is still at 12 o'clock (this is when it fires) & the rotor position will be in the same exact position in relation to the cap as it was before you twisted the rotor (which is giving it mech advance). You will see the magic trick, how the mech adv can shift the reluctor (& it does) and with the reluctor and rotor being solidly connected (& they are) how the rotor position (phasing) does not change in relation to the cap when it fires (tooth lined up with magnet). I know it to be a fact but I was awed when I saw the HOW of it right in front of me

It is Totally correct that the Rotor Will change position during Mechanical advance.

But, it wont Show, as in the vid shown above. Because the rotor/reluctor advancement happens Under the pickup plate with its driveshaft. The upper cap terminal and rotor phase/relationship wont see that movement. Nor will the Vid show that when Trend gets done, as compared to the vid above.

The upper cap terminal/rotor relationship, wont know if the 10* or so of rotation is from the mechanical advance or just the engines rotation. So there should be no movement in trendzs vid except for normal tolerance play. Nothing like seen in the first vid.


Now, add Vacuum advance into the equation, it will look like the first vid. The Wide terminal posts of both the caps and rotors are to compensate for the vacuums phase movement.

Just wanted to agree with Mike,P and a lot of others that the Rotors relationship Will change under mechanical advance.

But it will be between the shaft going to the engines side and not upstairs as seen by the cap. The engine will see the advancement by the earlier spark but the cap will not see it.

I flipped on this, almost did a flop back, but staying with the flip today. Maybe flop back tomorrow though.

YES that is what I am saying: the cap will see not see it & "it" being any rotor (phasing) change & that was my original statement that only vac adv will change RP (that mech adv will not change it). the rotors' relationship (phasing) with the cap will NOT change under mechanical advance. I am not speaking of reluctor movement or timing or anything else other than strickly phasing

What ever Rick shows I will abide by... period..
if it doesnt move the rotor.. I will have the wife
do her paypal thingy.. period.... good enough?
EDIT
And I will state on here.. if I'm wrong

Guys this is the moneyshot right from that article. It clearly states the rotor will move in relation to the terminal. It wont be any more clear than this. The idea is to get the phsecjust right so it will still work with the advance and not jump. That is the rest of the article.

You can have an adjustable rotor or a different reluctor to move the phasing to where it needs to be. Clocking might be another term that explains better for some.


How it Works
With most typical mechanical advance distributors, the weights and springs are located on a plate that also mounts the rotor. As rpm increases, centrifugal force pulls the weights against spring tension and moves the plate, which advances the rotor in relation to the spark plug wire terminals in the distributor cap. The plate that mounts the rotor is connected to the distributor shaft that also spins what is sometimes called a paddle wheel, or reluctor, with 8 lugs on it (for a V8 engine). When each lug passes by the magnetic pickup, it generates a signal that triggers the module to initiate a spark from the coil through the rotor, across the gap to the distributor cap post and on its way to the spark plug. . In a standard non-EFI application, the reluctor tabs pass the pickup at exactly the same time that the tip of the rotor lines up with the intended terminal inside the distributor cap. These two are in a fixed relationship with each other. Mechanical advance moves not only the position of the reluctor in relation to the pickup but also the rotor in relation to the distributor cap spark plug wire terminal.
Vacuum advance works in a similar fashion. When engine vacuum is applied to the canister, it pulls on the plate that mounts the pickup. By moving the plate in the opposite direction of the rotating shaft, this also advances the timing.
All of this motion affects the position of the rotor in relation to the spark plug wire terminal on the inside of the distributor cap at the moment that the signal is sent to the CD ignition box to “fire” the coil. Stock distributors align the rotor with the spark plug terminal on the distributor cap with the engine at the initial timing position, and since the reluctor and rotor are fixed together, mechanical advance does not cause phasing issues because as the trigger is advanced, so is the rotor. But performance engines with EFI or power adders that require retarded ignition timing combined with high output spark demands place undue load on the ignition system and place a premium on rotor phasing. Let’s take a look at a typical situation.

"mechanical advance does not cause phasing issues because as the trigger is advanced, so is the rotor."
That's from the article.

Your saying right there that the rotor advances..
thats what I have said all along

O.K. I'll take another shot at this
Lets say that when the reluctor is lined up with the pick up, a spark shoots out of the coil.(it may happen on the rising edge or falling edge, but lets make this easy)

When the distributor is at rest, and the pick up and reluctor are lined up with each other, the rotor is aimed dead center at the cap terminal.
I have the distributor here and I see this as true.

Now lets add 10 (distributor)degrees of mechanical advance.

This seems to be where everyone starts to disagree.

The way I see it: The coil will only fire when the reluctor and pick up are aligned.

The way some see it: The rotor is 10 degrees ahead of a cap terminal when the spark occurs.

Since a spark only occurs when the reluctor and pick up align, how can this be?

How is the spark triggered if the reluctor is not in line with the pick up?

Trendz would you take 3 minutes & do the dist test in your hand. You will see the "magic", how the last three statements will take place even tho it makes no sense. Just now I went into the kitchen & tried it again (just to keep my sanity!). EDIT Keep in mind, you are checking rotor position at idle/no advance so to speak in your kitchen with a tooth lined up with the magnet then you are moving the tooth a bit CCW then twisting the reluctor back CW so it will fire earlier (the mech adv) which is what would happen when running & the mech adv is advancing it and at that point when it fires (earlier) the tooth is lined up with the magnet and the rotor is back to its original position. MORE EDIT as the tooth/rotor come around CW the mech adv twists the reluctor/rotor even further CW so it reaches the magnet sooner (& it fires) & when the tooth reaches the magnet sooner the rotor will be in the same spot on the cap as it was before the mech adv bumped it forward. that is the "trick", that when the tooth (earlier) reaches the immobile magnet the rotor will always be in the same position.

Trend is agreeing with you, he doesn't need to see the magic.

Boy, no wonder this is so confusing for Everybody.

Agreed; As I backed you up on that.

But, you wont see it, as you stated like on the first vid, and as I thought it would too. You thought that vid was proof. It made me Totally rethink this through too, as it might be proof. But, trust me it wasn't. Lets wait for trendz vid.


The Rotor advances, No argument about that. Everybody, and I mean EVERYBODY, Get That out of the Way.

But , You wont see that action, like on the movement seen in the only vid shown so far. The Upper half of the distributer above the pickup plate doesn't know its drive shaft has advanced, mechanically. But the engine does.

Its just rotating in the same sinc as it has been before. Rotor/ reluctor/cap/pickup in the same exact marriage alignment.


So your half right, like most everybody else.

(1) Correct, the eng sees it cuz it fires earlier (2) Agreed, above the plates the marriage alignment (rotor phasing) between tooth/rotor/cap is the same/unaltered.

Ah what the heck... I'll muddy this up.

"The Rotor advances, No argument about that. Everybody Get That out of the Way."

This depends on your point of view. I contend that from the pick up's point of view, it does not advance.
From the pick up's point of view it stays exactly in the same place.
The mechanical advance puts the engine in a retarded state when it comes in.
The timing light will show the rotor staying in the same place, while the engine rolls away from tdc at the exact same time.

Depends on your point of view. Your right Glass half full or half empty.

Yep, the pickup sees it as the rotor has never moved. So it really doesn't see it{ Advanced Or Retarded} does it.

But I will argue the advance weights will throw the rotor forward compared to the engine rolling back under acceleration.

But, yeah, I don't think this thread needs any more Mud added in. Stop it Trendz.

And I do understand what your saying. Even though the weights are being thrown forward, the engine is firing from a retarded position from what is was before, with no advance. but the distributer is firing exactly as it was before.

Of course the firing event happens in the same place as far as the reluctor and pickup are concerned. The rotor will be ahead of where it was with no advance. It does not have to be spot on under the terminal to have the transfer of the spark.

The entire idea of even worrying about rotor phase is if you get a bad tolerance stack, it can be too far off where it needs to be in order for the spark to jump to the correct terminal. This becomes more crucial as the size of the cap increases. The referenced article goes into this. It is mind boggling we are page after page into this simple topic, with reference material no less, and i see people still talking about "magic" being involved. Starting to think this is an early April fools joke.

Before posting again to the contrary, go back and read that section i posted. As many times as it takes people. As many times as it takes.