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Which is better mechanical or vacuum advance distributor?
Vacuum advance offers greater better fuel economy and engine performance due to raised timing during periods of low speed such as gear shifting or stopping; it extends the combustion mixture burn cycle. Mechanical advance timing offers better engine performance in high speed applications such as race car driving.
What does the vacuum advance do on a distributor?
Under a light load and part throttle conditions, timing can be advanced. This improves throttle response and makes the engine more efficient. It also helps the engine run cooler. The vacuum advance provides this benefit BEFORE the Mechanical Advance provides Total Timing.
Does vacuum advance work at idle?
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.
Will a car run without vacuum advance?
Running without the vacuum advance costs you performance, driveability, and fuel economy, so disconnecting it to eliminate the misfire being caused by something broken or out of adjustment is a get-by band-aid at best.
What happens when vacuum advance fails?
Eventually the deterioration will reach the point that the vacuum advance no longer adjusts the timing, causing the vehicle to hesitate when the engine attempts to move the vehicle’s weight. In addition to this lack of power, a vacuum leak can also cause the engine to idle roughly or even stall.
What happens if you advance timing too much?
Ignition Advance Advancing the timing means the plug fires earlier in the compression stroke (farther from TDC). Advance is required because the air/fuel mixture does not burn instantly. It takes time for the flame to ignite the all the mixture. However, if the timing is advanced too far, it will cause an Engine Knock.
How much vacuum advance should I have?
This can be checked with the engine running at idle with a timing light. Make sure the vacuum advance connection is removed, and now rev the engine up to around 2,500 to 2,800 rpm. Ideally, the timing now should be somewhere around 34 to 36 degrees to total advance.
What should vacuum advance be at idle?
Do you have to run a vacuum advance?
For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum. Absolutely.
How do I know if my vacuum advance is bad?
To check the advance run the engine at a fast idle. Then disconnect the vacuum line while the engine is running. . The distributor should return to the same position it is in when the engine is not running.
Can too advanced timing cause backfire?
Usually, hard starting occurs when the ignition timing is too advanced, not retarded. An overly advanced condition will cause backfire through the carb and overly retarded will cause backfire through the exhaust.