2.0 Dizzy Question, Maybe I am just an Idiot Options

[Mblizzard]

Ok 73 2.0 built to a 2056. Currently running points. Checked dwell and set to specs. I was setting the timing and I have a timing light that you can set in the advance.

1st question: Can you use the advance setting on the timing light instead of the 27 at 3500 rpm?

2nd question: My dizzy has 2 vacuum ports. One is advance and one is retard. My throttel body only has one vacumm port for the dizzy. Do I need both hooked up?

3rd Question: Do I have the vacuum line on the correct (advance) side?



4th Question: when I check the timing (just for fun) with the vacuum hose hooked up as shown the timing is not anywhere close to 27 at any rpm. That seems odd.

[Java2570]

1) yes
2) if you only have the one throttle body port, only the one you have hooked up is correct;
the other side, you can just leave a hose open to air.
3) you have the correct side hooked up but I think it's actually retard not advance
4) Should be close to 27 degrees, what is it showing now? It could be slightly different
when you don't have a stock configuration but not by a lot.
5) you aren't an idiot to ask questions!
6) someone much smarter than I am will be along to chime in shortly.

[stugray]

Can you use the advance setting on the timing light instead of the 27 at 3500 rpm?

yes.
Push the rear tin back over the engine case.
You can see the flywheel 0 degree mark through the hole in the trans case.

Set the advance on the timing light at set it through there.

[TheCabinetmaker]

Remove the vacuum line and plug it when timing

[914_teener]

Yea...I was gonna say that....also, but I'm not SURE if the "cans" use a common diaphragm.

If you leave retard side off and the diaphragm is cracked that could present a problem, meaning a vaccum leak.

I think you might want to make sure both sides hold vaccum as well. There was another post that had several problems with the dizzy, that was one.

[Mblizzard]

I think I will try the advance light method as I have never been happy with the way the car runs doing it at 3500 rpm.

Both sides do hold vacuum.

[r_towle]

Looks to me like you have the vacuum line hooked up to the wrong port.

Rich

[Bleyseng]

That is the vacuum retard that the hose is hooked up to and should be plugged into the lower port on the TB. If you have only one port on the TB then this correct. When you time the engine pull it off the TB and plug it and the port on the TB. Time the engine to 28 degrees BTDC @3500rpms as you are using only the mechanical advance of the dizzy to set the timing. Then plug the hose back in so the vacuum retard is working which only works at idle.
Now adjust the idle speed.

[Mblizzard]

So we have a couple of differing opinions on the correctness of the vacuum advance hose connection.

After setting the timing and connecting the vacuum hose as shown, the engine speed decreases greatly. Which to me says that port is retarding the timing. When I switch sides, the engine speed increases.

Anyone have a definitive answer as to which side of the dizzy is advance and which is retard?

[Java2570]

Bleyseng is correct and every hose diagram I've seen shows it that way.....
This diagram shows both lines hooked up but the advance hose shown isn't used
by most people as the throttle body only has the one port, just leave it hanging
open to the air.

[r_towle]

So we have a couple of differing opinions on the correctness of the vacuum advance hose connection.

After setting the timing and connecting the vacuum hose as shown, the engine speed decreases greatly. Which to me says that port is retarding the timing. When I switch sides, the engine speed increases.

Anyone have a definitive answer as to which side of the dizzy is advance and which is retard?

It's a diaphragm hooked to an arm that moves the advance plates.

Open the top of the distributor and look at it.

When you apply vacuum to the port farthest away from the distributor, you pull the advance plate arms and thus add advance.
When you apply vacuum to the vacuum port closes to the distributor, you push the arm which retards the advance plates.


If you have no vacuum at all hooked up, the advance plates function only by centrifugal force and will eventually (at 3500 rpms) get to full advance.

The vacuum advance is to assist in helping you accelerate by adding in some advance earlier than at 3500 rpms to give you a smoother acceleration.

The vacuum retard is to help with emissions to retard the timing faster to reduce over run and higher idle, and burning extra fuel.

You set the timing with nothing hooked up so you are only using the centrifugal advance, thus why you need to set timing at 3500 rpms....so you know for a fact that you are looking at full advance.

Please explain your symptoms in this thread.....
How you are doing timing, and how lubricated the whole advance mechanism is might be affecting your results.

[r_towle]

Oh, put a hose on each port, one at a time and suck on the hose.
Be gentle, but you should be able to get the hose to stick to your tongue...then you know the vacuum canister diaphragm is not leaking...

[type47]

Anyone have a definitive answer as to which side of the dizzy is advance and which is retard?

Well, the workshop manual pg 2.1-1/2 identifies the port "facing away" from the dizzy (in your first pic in this post, it's the one without the hose connected) as the "Vacuum connection for advanced adjustment". The problem to me is it is not 100% clear which port on the throttle body to connect to. Looks to me to be the port before the butterfly plate.

[Mblizzard]

So we have a couple of differing opinions on the correctness of the vacuum advance hose connection.

After setting the timing and connecting the vacuum hose as shown, the engine speed decreases greatly. Which to me says that port is retarding the timing. When I switch sides, the engine speed increases.

Anyone have a definitive answer as to which side of the dizzy is advance and which is retard?

It's a diaphragm hooked to an arm that moves the advance plates.

Open the top of the distributor and look at it.

When you apply vacuum to the port farthest away from the distributor, you pull the advance plate arms and thus add advance.
When you apply vacuum to the vacuum port closes to the distributor, you push the arm which retards the advance plates.


If you have no vacuum at all hooked up, the advance plates function only by centrifugal force and will eventually (at 3500 rpms) get to full advance.

The vacuum advance is to assist in helping you accelerate by adding in some advance earlier than at 3500 rpms to give you a smoother acceleration.

The vacuum retard is to help with emissions to retard the timing faster to reduce over run and higher idle, and burning extra fuel.

You set the timing with nothing hooked up so you are only using the centrifugal advance, thus why you need to set timing at 3500 rpms....so you know for a fact that you are looking at full advance.

Please explain your symptoms in this thread.....
How you are doing timing, and how lubricated the whole advance mechanism is might be affecting your results.

The main symptoms are overall lack of power and poor fuel mileage.

[r_towle]

Remove the hose and cap it so you don't have a vacuum leak.
Stick a small bolt in the end of the hose and clamp it.

Then time it at 3500 rpms and see how it runs.

Hook up nothing to the vacuum canister.

[Java2570]

http://www.914world.com/bbs2/index.php?showtopic=136929

The answer of which side is advance and retard on the canister is answered in this link.

[Mblizzard]

Ok so I removed the hose from the regard side and switched it to the advance side. it runs much better. But if I read the posted link it seems that nothing should be hooked up to the advance side? That seems odd. I always remember at least one hose being attached to the advance side.

[Cap'n Krusty]

Time for me to check in. The diameter of the retard port on the TB and the one on the vacuum can are larger than the advance port and advance connection on the vac can. That in itself should make it clear which line goes where. With the throttle plate closed, there is significant vacuum on the retard port. If there's an advance port, there will be NO vacuum present at the smaller (advance) port on the TB with the throttle plate fully closed. If the hoses are connected properly (how can they NOT be, given the difference in port AND hose sizes?), the idle speed will be pulled down with the throttle plate closed, and it will rise significantly as the throttle is opened (as retard vacuum goes away). As the advance port vacuum gets stronger, the advance side of the can moves the plate and cause the timing to advance. There are NO variables here other than the strength of the vacuum signal and the freedom of the plate to move. None. It doesn't matter whether or not you unplug the retard hose when setting the timing at full advance, because it has no vacuum once the throttle is opened. Good habit to do so, though. As 914 TBs have no throttle stop adjustment for closed throttle, the plate should always be fully closed when at rest. If the cable is too tight, or the closed position has been artificially altered, that needs to be addressed. If the retard hose is attached to the advance port on the can, the idle speed will be way too high and the timing advance will only reflect the operation of the mechanical advance mechanism. Any questions?

The Cap'n

[barefoot]

OK, i have a ditzzy with both vacuum ports and am running Dello's, should i use vac advance ???
I don't care about emissions, just want best performance and fuel mileage.

[r_towle]

Time for me to check in. The diameter of the retard port on the TB and the one on the vacuum can are larger than the advance port and advance connection on the vac can. That in itself should make it clear which line goes where. With the throttle plate closed, there is significant vacuum on the retard port. If there's an advance port, there will be NO vacuum present at the smaller (advance) port on the TB with the throttle plate fully closed. If the hoses are connected properly (how can they NOT be, given the difference in port AND hose sizes?), the idle speed will be pulled down with the throttle plate closed, and it will rise significantly as the throttle is opened (as retard vacuum goes away). As the advance port vacuum gets stronger, the advance side of the can moves the plate and cause the timing to advance. There are NO variables here other than the strength of the vacuum signal and the freedom of the plate to move. None. It doesn't matter whether or not you unplug the retard hose when setting the timing at full advance, because it has no vacuum once the throttle is opened. Good habit to do so, though. As 914 TBs have no throttle stop adjustment for closed throttle, the plate should always be fully closed when at rest. If the cable is too tight, or the closed position has been artificially altered, that needs to be addressed. If the retard hose is attached to the advance port on the can, the idle speed will be way too high and the timing advance will only reflect the operation of the mechanical advance mechanism. Any questions?

The Cap'n

Just one question.

How many coats of plasti dip should I use on my magnesium transmission?