Re: Distributor vacuum and timing

Posted by HH56 On 2018/8/17 14:03:50

I'd like some clarification too as to how others do timing. Most mechanics I have watched seem to use the vac advance disconnected and line plugged method when setting the initial timing.

In the ignition systems training manual there is a statement in a line by itself to have the vacuum line tightened. Since they are discussing timing am assuming that means the vac advance line to dist. They go on to the procedure for doing a static setting with the engine not running by using a test light and setting the dist so the light just goes out as the points open at the chart recommended value (6 btdc for a 2106). A paragraph or so later it goes into using the neon timing light with engine running and also setting the dist at the chart value for the engine.

Question in my mind is what am I missing. How can both be correct when no vacuum would be present when setting static with engine not running and the test light yet the same degree mark is used with neon light and engine running. Presumably the vacuum advance is at full advance with the 18" or so idle vacuum so wouldn't the desired values be different?

The only caution Packard has about advances when setting timing is to make sure the engine is below a certain RPM so the centrifugal advance doesn't come into play. Haven't found a mention in the training manual or any SM of doing something with the vacuum.