Re: Vacuum Advance unit

Posted by Jack Vines On 2009/10/26 10:49:38

While we're at it, has anyone determined the total of how many distinct variants of specifications there were of the two types of distributor, Delco and Autolite?

1. Why a low-volume manufacturer such as Packard chose two different makes of distributors, two of 4-bbl carburetors, starters, generators boggles the mind!

2. The engineers went to a great deal of trouble to test and specify different vacuum and centrifugal advance curves for different horsepower and load applications. Too many owners/mechanics think because all the distributors physically drop in, they are interchangeable. Not so!

3. Because a vacuum advance unit can be made to fit a distributor, it may not be the optimum for the engine and car. The only way to do it right is off the car and on a machine. Yes, with great effort an approximation can be done on the car, per JW.

4. The proper centrifugal advance, vacuum advance and initial advance settings are crucial. The Packard is a high compression engine and running on the edge of pinging with today's crap fuels. If the ignition is not as it should be, damage much greater than the cost of a pro distributor rebuild can occur. I've seen pistons which look as if they were attacked with a tiny ball-pein hammer. That pinging which you hear or don't hear is a physical blow ringing through the walls of the engine.

5. Too many Packard owners cheap out and use regular 87-octane, "Because I don't drive it that hard." False economy if there ever was one. No fuels commonly available at the pump today are of sufficiently high octane for the Packard V8, but the 91+ are the least bad.

thnx, jack vines