Re: Distributors and advance curves - how many did Packard build?

Posted by Owen_Dyneto On 2010/6/27 18:41:47

An excellent method for timing "by ear" is to continue to advance until a HINT of preignition ping is heard with the engine under heavy load, for example accelerating up a steep hill under modest throttle. Most old-time mechanics considered this the optimum timing and I agree and have used this method for decades on many cars with total satisfaction. The key is, what's a HINT - answer, that you can just barely hear ping and it goes away under either more or less throttle.

If after establishing that, the starter balks a bit on a restart, just back off a hair.

As already noted, you can check the centrifugal advance with the timing light, comparing the advance in degrees with the specifications. For the vacuum advance, if you have a small hand vacuum pump with gauge (an extremely handy tool), you can do the same. Not as easy to do accurately as with a distributer bench-test machine, but good enough to determine that they are working reasonably.