Re: Tune up

Posted by Owen_Dyneto On 2021/8/26 17:07:41

Bear, the purpose of the distributor vacuum unit is to facilitate smooth, stumble-free engine speed increase when manifold vacuum drops (i.e. when the accelerator is aggressively depressed).

If your stumble was lessened when you blocked off the vacuum line, that most likely means your vacuum unit was defective (leaking, not able to hold a vacuum).

Sure, its possible to have decent performance without a distributor vacuum unit, Packards and others didn't have them as factory units until 1935. But its use gave more refined performance.