Hot Rod Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
156 Posts
Discussion Starter · #1 ·
Ok I was wondering about where to hook certain vacuum components, carb or manifold vacuum? Here's how I have it setup now.

Vacuum advance is hooked to the only manifold point. Hooked to smaller carb ports are the vacuum choke, EGR valve, and another line that runs up the firewall and into the firewall. :confused: From the rear of the carb is a large line that runs to the brake cylinder, and the front has another large one running to the PCV valve. The stock setup had an odd vacuum module on the intake manifold and one on the thermostat housing. Both of these, as well as the canister have been removed.

If I disconnect the line to the advance the engine slows, indicating that it is being advanced even at idle, which of course doesn't seem right.

Does this sound right? Everything seems to work aside from the advance. Also, does anyone know what the odd modules on the intake and thermo housing were?
 

·
Glad To Be Here
Joined
·
2,240 Posts
Gokussj5okazu said:
Vacuum advance is hooked to the only manifold point.

If I disconnect the line to the advance the engine slows, indicating that it is being advanced even at idle, which of course doesn't seem right.

Does this sound right?
This is correct for running full manifold vacuum for the advance.
 

·
Registered
Joined
·
156 Posts
Discussion Starter · #3 · (Edited)
Thanks Frisco. I'm not sure if the advance is meant for manifold or ported though. It's the stock dizzy, does anyone know? The sticker that shows the routing is gone or I'd just look for myself.

Will having the canister and those two vacuum modules disconnected hurt anything?
 

·
Glad To Be Here
Joined
·
2,240 Posts
Gokussj5okazu said:
Thanks Frisco. I'm not sure if the advance is meant for manifold or ported though. It's the stock dizzy, does anyone know? The sticker that shows the routing is gone or I'd just look for myself.

Will having the canister and those two vacuum modules disconnected hurt anything?
Most later model smog engines use the ported vacuum connection for the vacuum advance. They also have the initial timing set very low (0-6 degrees). This is too increase the temp at idle to help burn off the hydrocarbons at idle.

For performance (not for emissions testing) on non-computer controlled ignitions, using full manifold vacuum for the advance and increasing the initial timing considerably will yield much better overall performance that will be noticeable immediately.

As long as you have no open vacuum ports with the cannister and vacuum modules disconnected there should not be a problem as to the running of the engine. If you are required to pass a smog test with your vehicle you will need to have everything hooked back up as original.
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top