Distributor Vacuum Advance
Thread Starter
5th Gear
Joined: Sep 2017
Posts: 5
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From: Saxmundham Suffolk
Distributor Vacuum Advance
I recently bought a 1979 C3. It has a fairly new Chevy V8 350hp crate motor fitted, that I know little about.
The distributor vacuum advance is not connected! There is no hose going to the canister from the inlet manifold!
I am mystified why this has been done. Surely on a street car. which it is, the vacuum advance needs to be connected?
Could there be a reason why it's not connected? Any comments on this are welcome, thanks!
The distributor vacuum advance is not connected! There is no hose going to the canister from the inlet manifold!
I am mystified why this has been done. Surely on a street car. which it is, the vacuum advance needs to be connected?
Could there be a reason why it's not connected? Any comments on this are welcome, thanks!
Pro
Joined: Sep 2017
Posts: 516
Likes: 72
From: Modesto California
I recently bought a 1979 C3. It has a fairly new Chevy V8 350hp crate motor fitted, that I know little about.
The distributor vacuum advance is not connected! There is no hose going to the canister from the inlet manifold!
I am mystified why this has been done. Surely on a street car. which it is, the vacuum advance needs to be connected?
Could there be a reason why it's not connected? Any comments on this are welcome, thanks!
The distributor vacuum advance is not connected! There is no hose going to the canister from the inlet manifold!
I am mystified why this has been done. Surely on a street car. which it is, the vacuum advance needs to be connected?
Could there be a reason why it's not connected? Any comments on this are welcome, thanks!
The previous owner probably had an ignorant friend who advised him to disconnect it to make the engine more powerful.
Team Owner
Joined: Jun 2001
Posts: 23,379
Likes: 1,067
From: Virginia USA
I run without my vac can hooked up right now but you don't really need it. I find off idle throttle response a lot better driving around town. The only drawback is yes, you lose some gas mileage and it runs a little hotter.
My timing is 8 degree initial and 36 degree all in at 2800 RPM.
I will hook it back up if I go on a long highway cruise to get better mileage.
My current can has too much advance and is the reason I don't use it. I really need to make a limiter for it but I'm too lazy. That or get an adjustable one or one that limits total vac advance to 10 to 12 degree.
My timing is 8 degree initial and 36 degree all in at 2800 RPM.
I will hook it back up if I go on a long highway cruise to get better mileage.
My current can has too much advance and is the reason I don't use it. I really need to make a limiter for it but I'm too lazy. That or get an adjustable one or one that limits total vac advance to 10 to 12 degree.
