vacuum advance

[hdbob5454]

just set timing on my 70 350, reconnect vacuum and the timing stays the same, time for a new one?

 

[Classics Fan]

What did you set initial timing at, and at what idle RPM? Does it stay the same only at idle or also with increased throttle/RPM? Do you have vacuum connected to a ported or manifold vacuum source?

 

[hdbob5454]

it was at 10 decided to leave it my old firebird was 10, when I connect vacuum nothing changes going to change it, didn't check mech advance yet.

 

[melsg5]

Did you put your finger over the port that the hose is connected to see if there was vacuum?
There are two types of vacuum advance connections, ported, intended for emissions purposes provides no vacuum at idle, the other is manifold which provides vacuum at idle and cruising and is the preferred type if emissions is not a concern.

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[hdbob5454]

I pulled the dist cap and used a vacuum pump and watched it move , I moved the vacuum line to different port and its working now, idle went up when I connected it, haven't had a chance to drive it yet probably this week. thanks let you know how it drives