What is this part?
Connoisseur d'Junque
Joined: Sep 2010
Posts: 21,183
From: The Hudson Valley
It's a Distributor Vacuum Control Switch.
It diverts full vacuum (instead of ported vacuum) to your distributor vacuum advance at certain times in order to reduce oxides of nitrogen.
Basically, it sets the timing correctly on rare occasions, so that it can be set way too retarded the rest of the time in order to reduce emissions.
You don't need it if you set your advance properly (that is: not according to the factory settings) in the first place.
Don't throw it out, though - that's what everyone else did in the '70s, and there are a few all-out restorers out there who are looking for them.
- Eric
It diverts full vacuum (instead of ported vacuum) to your distributor vacuum advance at certain times in order to reduce oxides of nitrogen.
Basically, it sets the timing correctly on rare occasions, so that it can be set way too retarded the rest of the time in order to reduce emissions.
You don't need it if you set your advance properly (that is: not according to the factory settings) in the first place.
Don't throw it out, though - that's what everyone else did in the '70s, and there are a few all-out restorers out there who are looking for them.
- Eric
Thread Starter
Registered User
Joined: Sep 2012
Posts: 140
From: Hamilton, Ohio
It's a Distributor Vacuum Control Switch.
It diverts full vacuum (instead of ported vacuum) to your distributor vacuum advance at certain times in order to reduce oxides of nitrogen.
Basically, it sets the timing correctly on rare occasions, so that it can be set way too retarded the rest of the time in order to reduce emissions.
You don't need it if you set your advance properly (that is: not according to the factory settings) in the first place.
Don't throw it out, though - that's what everyone else did in the '70s, and there are a few all-out restorers out there who are looking for them.
- Eric
It diverts full vacuum (instead of ported vacuum) to your distributor vacuum advance at certain times in order to reduce oxides of nitrogen.
Basically, it sets the timing correctly on rare occasions, so that it can be set way too retarded the rest of the time in order to reduce emissions.
You don't need it if you set your advance properly (that is: not according to the factory settings) in the first place.
Don't throw it out, though - that's what everyone else did in the '70s, and there are a few all-out restorers out there who are looking for them.
- Eric
Old(s) Fart
Joined: Mar 2007
Posts: 50,803
From: Northern VA
You might want to read this thread on electric chokes:
https://classicoldsmobile.com/forums...ke-wiring.html
Connoisseur d'Junque
Joined: Sep 2010
Posts: 21,183
From: The Hudson Valley
- Eric
Old(s) Fart
Joined: Mar 2007
Posts: 50,803
From: Northern VA
Actually, the green/white wire is fed from the 20A backup lamp fuse. 20A is what GM used on factory electric choke setups. I would still use an oil pressure switch to prevent the choke from heating up prematurely with the engine not running.
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