Is vacuum timing a motor reliable at all? This old guy told me that he has always done it to his vehicles. Hook up a vac. guage to your intake and turn the distributor till you get the most vacuum. But when he did it to mine it pinged like crazy.

Just curious if this methond is "WAY OUT THERE"

We also used it to set the mixture screws on my carb. But I saw this in Car Craft so I believe this is a good method for that.



What does everyone think?

Thanks

 

i wouldn't say it's "way out there" and it is a way to set timing, but it isn't the best method. use a timing light.

 

Tuning the mixture screws to get the most vacuum at idle is a valid way of doing things. Timing, however- no. Start at the stock setting and work up 2* at a time until it either has detonation or slows down (timed acceleration runs).

 

I've done that on older 70's carbed cars and have always been within 2-3* of factory timing. Now enter the computer controlled distributors....doesn't work. You have to set the timing as stated in the shop manuals to eliminate the computer's control over the spark, otherwise you are just shootig in the dark.