Where to hook up vacuum advance distributor

How do you test the vacuum advance on a distributor?

There are a couple of ways to test the vacuum advance on vehicles equipped with distributors. Mechanics prefer to use an inductive pickup timing light.

How do you set the vacuum advance?

You want to plug the line to the vacuum advance when setting the timing. After setting the timing, hook the vacuum line back up and adjust your idle speed if necessary. When checking you mechanical (centrifugal) advance, the vacuum line must be plugged as well. Man.

Which port do I connect the vacuum advance to?

Which port you connect the vacuum advance to will ultimately depend on your combination. I can tell you the factory used a basic rule of thumb to determine which port the hose was connected to. If a vehicle had a manual transmission, it was connected to a ported vacuum source.

How does vacuum advance work?

This is how vacuum advance works. At part throttle, high manifold vacuum moves the diaphragm in the vacuum advance canister on the distributor to add more timing. But at WOT, the vacuum drops to near zero and vacuum advance is removed and the total timing then is established by the initial plus the mechanical advance.

How does a vacuum tester work on a distributor?

The diaphragm moves a rod that turns a sliding plate at the base of the distributor, which can be seen with the naked eye. A few pumps of a manually operated vacuum tester should provide a full advance, and the sliding plate should stay in place until you remove the vacuum from the port.

How do I know if my vacuum distributor needs replacing?

Suck on the vacuum pipe until you can see the base plate inside the distributor moving. If you can keep sucking on the vacuum pipe (and the base plate does not move) and not maintain vacuum then this means that the diaphragm inside has split and the unit will need replacing.

Why should I retain the vacuum advance on my distributor?

So there are significant advantages to retaining the vacuum advance on your distributor. In the case of the HEI, you can actually purchase an adjustable vacuum advance canister that will allow you to custom-tune the amount of timing advance.

How do you test a vacuum advance on a car?

A few pumps of a manually operated vacuum tester should provide a full advance, and the sliding plate should stay in place until you remove the vacuum from the port. Even if your cars vacuum advance is working properly and holding negative pressure, there could still be a problem with the vacuum signal itself.

What is a vacuum advance?

The vacuum advance is an Ignition Timing control mechanism built into some distributors. It is made up of: An advance plate attached to the trigger mechanism inside the distributor. How does it work? As Engine Vacuum rises, it pulls on the diaphragm inside the canister. The diaphragm is connected to the advance plate by a linkage.

How does a vacuum cleaner advance plate work?

As Engine Vacuum rises, it pulls on the diaphragm inside the canister. The diaphragm is connected to the advance plate by a linkage. The movement of the linkage rotates the trigger mechanism. This causes the ignition to be triggered sooner (advanced).

What is the difference between vacuum advance and diaphragm action?

The vacuum and diaphragm action have the same effect on electronic ignition systems. The vacuum advance system will only work if the piping from the carburettor to the diaphragm, the diaphragm itself, and the diaphragm chamber on the carburettor side are all airtight. Carry out the following checks; First, remove the distributor cap.