So in observing how the cap and rotor behave on the distributor, i made some realizations about the entire distributor assembly. Please let me know if these statements are true, in the interest of further understanding:

1) Contained within the distributor are two related items that are not exactly connected: the distributor itself (cap and rotor) and the crank angle sensor.

2) The only way they are connected is by the rotating shaft connected to the exhaust cam on the 4ag. otherwise, they would be able to operate independently if they were connected by the rotating mass of the engine. Meaning, they are not electronically dependent on one another.

3) When setting the timing on the 4ag, the rotating one does to the distributor unit (which looks like it's up to 6 or 7 degrees of range) is actually setting the angle of the crank angle sensor, which advances or retards ignition timing.

4) When setting the timing on the 4ag, the rotor position does not change; the rotor position is fixed on the gear connected to the exhaust cam.

Here is a question based on #4: when rotating the distributor, the cap changes position. Is this related to ignition timing, or is the brush on the rotor always connected when it touches the plug wire's tab, hence the 4 or 5 degree range of the rotor's brush tip? If cap position related to rotor position is important to setting timing, i would like to know.

Here's another question: when using a 20v distributor relocation kit, it doesn't appear to have the ability to rotate the cap. does this answer the previous question that the cap position has nothing to do with timing, as long as the rotor is pointed to #1 when the timing marks are set to TDC?

Thanks in advance.

R

i believe the 20v relocation kits timing, is as you recognized on the 16v dizzy, rotating the crank angle sensor as per original. Though it may not appear to be adjustable im sure it is. couldnt hurt to call SQ engineering.

Thanks for the quick reply. I appear to have put this in the wrong section. Mods please move. Thanks.

R

for ignition timing, you dont necessarily have to rotate the cap in order to advance or retard timing as long as its fixed in the right position to begin with. it gets a lot more clearer once you run coilpacks because once i did, i completely removed the cap and rotor while retaining the distributor itself as a cam angle sensor. now im running batch fire so they all spark at the same time off the coil, but if i rotate the original distributor itself, itll advance and retard as it once did before, absolutely no difference except i have to run a spare spark plug wire from coil pack 1 to the spark in order to do timing.

what Duy~ said is right, it becomes more clear when you start to mess with it, Battery power (12v) to coil which steps up the voltage 100x then from coil to distributor and the distributor transfer the spark to each spark plug by brushing the rotor against each post, the posts are in firing order of the engine, by moving the dizzy you are physically moving when the rotor contacts posts. where as a COP or CNP coil pack ignition system, takes an ignition module which is basically another pcm designated to ignition timing, and it gets its position from either the cam sensor or the Crank sensor (hall effect, electromagent, or photo electric sensor) thus knowing where the crank is, the ignition computer allows current to the coilpack(s) and from there it steps up the voltage to push to the spark.

Turtle wrote:So in observing how the cap and rotor behave on the distributor, i made some realizations about the entire distributor assembly. Please let me know if these statements are true, in the interest of further understanding:

1) Contained within the distributor are two related items that are not exactly connected: the distributor itself (cap and rotor) and the crank angle sensor.
R

It is very important that you use the right terms. I am confused because your description makes little sense to me.
A crank angle sensor would be found on the crank so no there is no crank angle sensor on the 4AGE.

There are two sets of pickups below the cap that could be considered a cam angle sensor or a dizzy position sensor. They send a signal to the ECU so it knows where the dizzy is and how to adjust timing.

2) The only way they are connected is by the rotating shaft connected to the exhaust cam on the 4ag. otherwise, they would be able to operate independently if they were connected by the rotating mass of the engine. Meaning, they are not electronically dependent on one another.

This makes no sense to me. They are connected by the rotating shaft, yes. No they cannot operate independently. Not sure what it has to do with the rotating assembly. They are electronically dependent on each other. The pickups tell the ECU exactly where the distributor it. They need to maintain their relationship to the cap.

3) When setting the timing on the 4ag, the rotating one does to the distributor unit (which looks like it's up to 6 or 7 degrees of range) is actually setting the angle of the crank angle sensor, which advances or retards ignition timing.

When adjusting the timing you are moving the cap and the pickups on the dizzy so it all changes in perfect relation to each other. The trigger wheel and the cap stay still as the cap and pickups rotate.

4) When setting the timing on the 4ag, the rotor position does not change; the rotor position is fixed on the gear connected to the exhaust cam.

Right, the cap rotates along with the trigger wheel pickups.

Here is a question based on #4: when rotating the distributor, the cap changes position. Is this related to ignition timing, or is the brush on the rotor always connected when it touches the plug wire's tab, hence the 4 or 5 degree range of the rotor's brush tip? If cap position related to rotor position is important to setting timing, i would like to know.

The ECU controls the timing. The ECU knows where the trigger wheel is from the input to the pickups. Rotating the dizzy advances and retards the timing because you are advancing or retarding the location of the pickups. The ECU will trigger the spark at the same time in relation to the cap and rotors position to each other because the pickups and the cap are rotating together. So let's say the ECU triggers spark when the rotor is exactly centered over the rotors contact then as you rotate the dizzy it will continue to fire in the same location in relation to each other.

1) understood. I don't claim to know everything, so thanks for the corrections. Dizzy position sensor makes more sense.

3) "When adjusting the timing you are moving the cap and the pickups on the dizzy so it all changes in perfect relation to each other. The trigger wheel and the cap stay still as the cap and pickups rotate" I just had my "a-ha" moment. thanks for this bit of info. There's a trigger wheel. So even though the pickups in the cap makes contact with the rotor, it's the trigger wheel in the sensor that tells the ECU to fire the coil. That is of big help.

4) thanks for confirming that and adding that the trigger wheel and the rotor position are fixed.

"The ECU controls the timing. The ECU knows where the trigger wheel is from the input to the pickups. Rotating the dizzy advances and retards the timing because you are advancing or retarding the location of the pickups. The ECU will trigger the spark at the same time in relation to the cap and rotors position to each other because the pickups and the cap are rotating together. So let's say the ECU triggers spark when the rotor is exactly centered over the rotors contact then as you rotate the dizzy it will continue to fire in the same location in relation to each other."

great to know. now i understand.

I was studying the 20v distributor relocation kits on google image and saw that some retain the dizzy position sensor and some only relocate the cap and rotor. Which didn't make any sense to me because wouldn't the rotor be going in the incorrect direction? Then i thought all you have to do is change 2 plug wires and it will work based on the opposite direction, as long as the rotor is pointed at 1 when the timing is set. But then it becomes trickier if the cap and rotor are separated from the sensor as they might both need to be synched up independently. anyways, thanks.

R

Hi all, in relation to the above - anyone running split distributor relocation kits figure out how to truly sync the timing?

PT86 wrote:... anyone running split distributor relocation kits figure out how to truly sync the timing?

While I don't have a relocation kit, the procedure should be straight forward

The shaft of the OEM distributor is fixed (keyed) to one end of the camshaft.
And the moving part of the relocation kit is fixed to the other end of the same
camshaft. Possibly, the moving part is indexed to the knock pin, in which case
it should already be synchronized with the OEM distributor shaft. Otherwise it
will be clamped by the cam pulley bolt, and can be rotated to any position.

EDIT: I had written "base" instead of "shaft" above, which is obviously wrong

To check or set the synchronization, set the engine with #1 cylinder at TDC on
the compression stroke (zero degrees on the crank pulley scale). Then adjust the
distributor base so that the distributor is in the middle of its adjustment range.

Put the engine into diagnostic mode to lock the timing. Then using your timing
light on #1 cylinder, adjust the position of the kit moving part until the light
shows 10 BTDC on the crank pulley scale. That would be pretty close as the FSM
says base timing should be in the range 8-12 BTDC, which puts 10 deg in the
middle of the adjustment.

Cheers... jondee86