Why does a distributor have a vacuum?
Why does a distributor have a vacuum?
Vacuum advance works by using a manifold vacuum source to advance the timing at low to mid engine load conditions by rotating the position sensor (contact points, hall effect or optical sensor, reluctor stator, etc.) mounting plate in the distributor with respect to the distributor shaft.
What is the purpose of vacuum advancer in the ignition system?
Plugging your vacuum advance into a direct source will allow it to engage at idle, which is good for a number of reasons. Much like cruise conditions, engines run leaner at idle than they do under load. Again, this means the mixture burns slower and needs an earlier spark to optimize the burn.
Why do you need a distributor with vacuum advance?
So based on this, you can see that having a curve in the distributor along with vacuum advance is a good thing as it reduces low-speed timing where the engine might detonate with too much timing but it can also benefit from more timing at part throttle than what is required at wide open throttle.
Why is my vacuum advance not working properly?
Even if your car’s vacuum advance is working properly and holding negative pressure, there could still be a problem with the vacuum signal itself. There are two different kinds of vacuum sources provided to the distributor advance diaphragm. Some automobiles use ported vacuum pressure, while others use manifold vacuum pressure.
When do you disconnect the vacuum hose from the distributor?
The distributor has a mechanical and vacuum controlled timing advance in/at the distributor . You disconnect the vacuum hose to adjust/ check the ignition timing . When finished , you reconnect the vacuum hose and set the base idle speed . Your “ experiment “ of disconnecting / plugging this hose will decrease power & gas mileage .
What does a vacuum advance control unit do?
The vacuum advance control unit on the distributor is intended to advance the ignition timing above and beyond the limits of the mechanical advance (mechanical advance consists of the initial timing plus the centrifugal advance that the distributor adds as rpm comes up) under light to medium throttle settings.
So based on this, you can see that having a curve in the distributor along with vacuum advance is a good thing as it reduces low-speed timing where the engine might detonate with too much timing but it can also benefit from more timing at part throttle than what is required at wide open throttle.
Even if your car’s vacuum advance is working properly and holding negative pressure, there could still be a problem with the vacuum signal itself. There are two different kinds of vacuum sources provided to the distributor advance diaphragm. Some automobiles use ported vacuum pressure, while others use manifold vacuum pressure.
Why do I need a ported vacuum advance?
Ported Vacuum advance is for cruising around at partial throttle settings where maximum economy is important as throttled operation has a less dense mixture that takes longer to burn, hence the extra timing from the vacuum advance. It costs NOTHING in the form of power output to use ported vacuum advance.
What kind of vacuum plug does a distributor use?
Hello everyone, I have a HEI distributor with the vacuum advance, 454 motor, and a 750holley carb. Was talking to a Summit sales guy and he said most guys plug their vacuum for their distributors.
