are distributors indxed the same from the factory?

so odd question. I know when I have replaced a distributor before, say a factory for mallory, I have to find TDC again and get the distributor pointed correctly since we only have 0 and 180 for how they fit in the motor.

but if I pulled a factory one from my car and another from another car, is the slot cut for the rotor matched to the slot cut for the gear?

or will it be luck of the draw?
will any factory distributor line up like the original or do they randomly cut the slot for the rotor?

I would think the factory distribs are indexed much closer to each other than some aftermarket(mallory) etc.

I would think that the OE ones would be pretty much the same for phasing. If a person ain't using vac adv you can install/pump up the can till the phasing is dead on then drill straight down at that point thru both plates then lock em in that clocking with a thin grade 8 bolt/nut with a spacer inbetween the plates to keep em parallel when you tighten down the nut. In operation only the vac adv can changes phasing. You can redrill the reluctor and Eberg sells the redrilled reluctors that I believe Andy used to sell. I ain't done it yet but I think a person could make another notch on the other side of the dist shaft with the OE notch that the rotor currently fits into, just offset the new one (measure thrice) clocked correctly and I wondering if a person could file the present OE notch sideways in the direction that it needs to go then JBweld the other horizontle wall back to get the notch width back its original dimention. The shaft is stout & I dont think a second notch would compromise its integrity. Generally you want the rotor to swing equidistant on either side of the centerline of the cap terminal & reducing the rotor tip to cap terminal radial clearance to .015" helps phasing as its the total distance (circumferential+radial) that if it is too great it will misfire expecially under load when the required voltage is the greatest. NAPA has an Echlin brand rotor (MO3000) for $8 & change out the door that has a .060" longer metal blade but you can easily fab your own & get the clearance exactly where you want it (the .015" for your exact dist tolerances (clearances).

Which motor are you working on? BB, SB, early Hemi or?

2000 magnum.
just wanted to see if I replaced the shaft, or entire distributor if it would line up the same, or require rotation to get it to line up.

Lineup the rotor to point in the same direction as the old dist, and swap it in. Providing no one has screwed up before you got there.
The dist will be indexed the same, as long as its the correct dist for the motor. If in doubt, bring # 1 up on compression and do it the right way. Gene

Timing from scratch is the best way. A tdc stop is all you need and easy to make with a bolt and old spark plug.

What problem are you trying to solve? Something real or perceived? Are you being proactive or reactivate?

this goes back to the megasquirt thing again.
I indexed the distributor like it says to and got it to give actual timing finally vs what it thought it was.

but the angle it is sitting at is bad for the software.
anything between 15-50 is bad according to the book.
I understand now, but it didn't explain. basically anything in the range that it might have to fire off for timing cannot be handled by the software because it cannot fire anything before it gets the signal.
it has a 5 degree delay so anything in that range is going to be 5 degrees less as well.

but anything over 90 degrees is a no go as well. Since obviously it cannot know it is going against a different tower on the distributor cap.

I am at 28 degrees right now. 1 more post over puts me at 118. one post less and I get into -72.

If the shaft was indexed differently I might be able to find one that splits the difference.

I asked in another post about changing the slot orientation.
I think that might be my solution, depending on how much it is adjustible.

If I can split the rotor between two posts moving over 1, I might be able to get somewhere into the 60's in the degrees and make it all finally work.

Are you using a crank sensor? If not, realigning the dist slot won't make. A difference. All that really does is move the plug terminals, it doesn't change dist phasing.
If you have a crank sensor for timing, then yes realigning the slot can change the phasing, but so does just turning the dist housing in the block.

Got a pic of the dist guts?

modified magnum distributor. no crank sensor at all.
a shutter wheel was added to it, so it gets a signal for each plug.

On my (non computerized) dist top shaft the circumference is 2.004" and the rotor slot width (straight line distance but still pretty close) is .238" so you have alot of room to either cut a new (reclocked) rotor slot or widen/jb weld the existing one to reclock it slightly as needed IF this will solve the problem. The shaft is thick/sturdy and the rotor is light so I dont there'd be a strength issue

Is that a set screw or a roll pin holding the wheel on?

If a cset screw, good you can adjust the position of the shutter to better align with the rotor.

If its a roll pin, your going to have to drill another hole in the shutter wheel to get things phased.

All your problems are in the distributor, moving the oil pump shaft won't change that.

Robert, not sure if that is easier than drilling another hole. but it is a thought.

it is a roll pin holding it in place.

so I am not sure why move the oil pump shaft won't help.

if I understand the issue, and maybe I don't.

The sensor that picks up the shutter wheel must be 50 to 90 degrees away from the rotor pointing or it doesn't work very well.

Since I can rotate the distributor at will and repoint number 1, getting some degrees distance isn't an issue.

Since this is measured at the crank and not the distributor, my issue now is moving it over 1 tower is equal to 90 degrees on the crank.

If I can move the oil pump shaft to split the distance between 2 towers, I get 45 degrees movment which puts me at around 65 ish to 70ish distance and makes it good.

Unless the gears mesh out farther than a tower on the cap that is.

what am I missing?

Your timing pickup is in the distributor, not on the crank.

You need three things lined up/timed correctly, #1 piston at tdc, rotor pointing at #1 terminal, and pickup at the specified location. Skipping the drive gear one tooth is the same as rotating the distributor. The rotor and pickup are in fixed positions relative to each other.
Relocking the shutter on the shaft is the best way to correct this.

I think you are mistaken.
the rotor pointing to number 1 is not fixed. by rotating the distributor and reindexing where number 1 is on the cap, I can change the relative position between the pick up and the rotor/number 1 on the cap.

Now Megasquirt needs the degree angle difference based on the degrees on the crank, between when the sensor in the distributor gets the first signal and where number 1 rotor is pointed.

a change in where number 1 is pointed by just shifting plugs on the cap by 1 plug tower, changes that by 90 degrees.
but that is too much as it would put me past where the software can handle it.

If I can get it to move only half the distance then I should be good.
I believe I can do that by moving the gear allowing the line up to be less than before.
I have to figure out which way and all, but I believe that should work.

Close. The gaps in the shutter are fixed relative to the shaft, so is the rotor. Yes you can make the rotor point to any terminal and that can be done by rotating the hosing or rotating the shaft (which is what happens when the engine runs) BUT the pickup is attached to the distributor housing, so rotating the housing does not change when the signal is generated vs where the rotor is. It DOES change where the signal is compared to the crank. You can keep cranking the dist til you get the timing number you want BUT the rotor won't be in the correct place, it will be probably 45* off from any terminal.

OK went back and reread this thread. First I missed Robert's mention of making a second slot for the dist. Yes that would have the same effect as moving the shutter wheel on the shaft.
But I think we lost track of the original problem by going down the phasing rabbit hole.
8t would help if you just had one thread about this just to keep information together rather than trying to figure out which thread has what info.

So what symptoms are you having? Not what you think it means but what is fact.that's not to be mean or rude but to keep things simple.

So far I gather that ms isn't happy with a degree spec. But the question is what does this spec measure?

Right now I have a degree spec of 28 degrees between the pick up and were number 1 points on the distributor.

anything between 15 and 50 is a no go for them because it might run into actual timing causing an issue software wise.

DIY tuned a 318 and said it needs more advance than 28 degrees, so I need to move it out farther.

I understand moving the wheel or moving the slot makes a difference but it seems repointing 1 makes a difference as well.

if not why not?

moving it one post and adjusting changed it from 20 to 28.
what is different from moving a post to moving the oil gear and turning?

OK to be clear, if the dist rotor is pointing at #1 terminal, the pickup/sensor was passed 28* prior?

The sensor is attached to the dist housing and the cap is also. I'm assuming both are "keyed" to the housing in order to maintain their positions. The fact that the rotor spins iin relation to those points is irrelevant. It has to spin.
This is distributor phasing.
There are several ways to change the phasing, as mentioned before we can realign the rotor to the shaft, we can realign the shutter to the shaft, we can realign the cap to the housing or we can realign the sensor to the housing.
What I'm trying to get to though is if this is whats needed.
So how is this 28* number determined? Is it something the ms system measures during setup? Is it something you program in?
Without separate cam and crank sensors this is not something ms can measure itself.

Also, think about this, you have 8 flags on the shutter wheel, one for each cylinder and they should be an equal 45* apart. The same can be said for the cap terminals. Basically you can make any terminal #1 and any flag #1 but they should still give you the same 28* reading unless something is machined wrong.

This leads me to question the statement that this 28* is a measure of the spacing between the pickup and terminal. Is it actually the measure of the difference between TDC and the pickup? That makes ore sense.
To answer your last question, it depends on what this 28* is measuring. If it measures the space between pickup and rotor, then relocking the drive gear has no effect. If it measures the degree change between crank and sensor, then yes it may help.

In either case the phasing of the rotor to terminal will need to be checked and adjusted. But we need to get the first problem fixed. Rephasing the rotor is easy.

so, yes each cap is 45 degrees apart. BUT that is 90 degrees movment at the crank.

it is programmed in. you have to dial it in based on the timing you see vs what the computer says it should be and change an indexing setting to allow it to know where it is.
the instructions basically said to use the crank degrees to see where it was placed.
it does matter where number one is pointed in relation to the vanes.

it hits a vane first then fires. the computer then has time to know when to fire. vs a vane hits and that is where number 1 is on the rotor.

the distance between the sensor and rotor is variable. since that is what it is based on for firing.

Yes 45 dist degrees is 90 at crank.

OK so "the timing you see" meaning you are checking timing with a timing light? Is that with a dial back light or a fully degreed balancer? Did you verify that TDC mark is correct?

Third paragraph is expected.
That last statement about the variable distance between sensor and rotor is a bit confusing. Do you mean that one flag or gap on the shutter is a different size than the others? That's how most other systems determine #1 location.
This implies you are going SFI vs batch fire, is that correct?

it is batch fire.
so all the slots are uniform.
where ever the pick up is, when ever it sees a vane, it will fire.
by making sure the rotor is lined up to number 1 when it fires, I ensure that it is correct.

I have to tell the system where number 1 is from that vane. because it can change.
and it is based on degrees at the crank. not degrees at the distributor.

and yes I verified tdc and where number 1 pointed first.

so right now timing is "correct", but in the no fly zone. I need to move it out.

OK that clarifies alot.

So what happens when you adjust the sensor to the correct location? I'm assuming the engine runs poorly or not at all(backfire through carb, severe miss etc)

This actually does bring us back to distributor phasing. If you turn the distributor housing the needed 22 or so degrees, the rotor no longer points at a terminal in the cap.

You can try to remap the timing program AND set the sensor in the correct position to verify this. For example put in 30 degrees of retard at idle and rotate the dist housing 30 degrees (advanced) to put the sensor in the right position.
Does the engine run? Poorly probably but it should idle.