rich weyand
Full Access Member
- Joined
- May 28, 2014
- Posts
- 967
- Reaction score
- 177
- Location
- Bloomington Indiana
- First Name
- Rich
- Truck Year
- 1978
- Truck Model
- K10
- Engine Size
- 350
Yes, run vacuum advance, for all the reasons mentioned. And run it on manifold vacuum.
Race cars usually don't have vacuum advance, because it's another thing to break and they don't run them outside the performance window where the vacuum advance would be active anyway.
Vacuum advance went on cars starting in 1938. Before that there was a spark advance lever on the left side of the steering wheel where the turn signal stalk is now. Vacuum advance was almost always (there were a *very* few exceptions) hooked to manifold vacuum until January 1, 1968. Hooking the vac advance up to ported vacuum was part of pollution controls, because it dumped burning mixture into the manifold to clean up NOx and CO emissions at idle. It also made engines idle hot, so there was often a temp sensor that would switch it to manifold vacuum if the engine got hot.
See here:
Article on ignition timing
Race cars usually don't have vacuum advance, because it's another thing to break and they don't run them outside the performance window where the vacuum advance would be active anyway.
Vacuum advance went on cars starting in 1938. Before that there was a spark advance lever on the left side of the steering wheel where the turn signal stalk is now. Vacuum advance was almost always (there were a *very* few exceptions) hooked to manifold vacuum until January 1, 1968. Hooking the vac advance up to ported vacuum was part of pollution controls, because it dumped burning mixture into the manifold to clean up NOx and CO emissions at idle. It also made engines idle hot, so there was often a temp sensor that would switch it to manifold vacuum if the engine got hot.
See here:
Article on ignition timing
