2f Carb Tuning - Timing - and Vacuum Routing for Desmog (1 Viewer)

[dannyvp]

Vacuum Check for Desmog.

BVSV 1 - Removed
BVSV 2 - Removed
EGR - Removed
HAC - Removed
Choke Breaker - Removed
Choke Opener - Removed
VTV - Removed

Vacuum Tube Routing
HAI to HIC port A
HIC Port B to "T"
Carb Advancer Port to Vacuum Advance on Distributer
Distributer HAC Advance Port to Filter Canaster
Distributer Vent 1 to Air Intake in Cab - through fire wall
Distributer Vent 2 to Air Breather
PCV Valve to Manifold and HIC Port to "T"

Does this sound right?

 

[dannyvp]

Any idea on this hose/tube?

 

[OSS]

Does this sound right?

No

That desmog pdf goes way way farther than is necessary, removing every last vestige of anything that wasn't part of a stripped & simple 1960s era engine.
In my opinion, that "desmog guide" does such a disservice to the poor soul who follows it. Way more stuff is removed than is necessary and usually to the detriment of engine performance.

There's only 3 smog components that alter the engine performance negatively: the EGR valve, the Air Pump (very marginally) and the catalytic converter.

The EGR can be disabled just by plugging a vacuum hose (then getting the distributor recurved). The Air Pump can be swapped with an idler pulley, and the cat (if you dare) can be swapped with a straight pipe.

Of those 3 things, the greatest performance improvement will be deleting the cat, with the EGR plug following a close second.
Removing the air pump really isn't noticeable, but it takes up a lot of space and creates a lot of clutter.
Removing anything else makes the engine worse.

 

[g-man]

vacuum line that goes to the front edit (driver's) side of the stock oem carb next to the ICS

 

[g-man]

I think it goes around to the other side of the firewall and from there another soft line to the (edit) charcoal vacuum canister.

 

[dannyvp]

vacuum line that goes to the front edit (driver's) side of the stock oem carb next to the ICS

So it should be hooked up somewhere? It’s just plugged right now.

 

[g-man]

I'll go take a pic of my carb.

 

[dannyvp]

No

That desmog pdf goes way way farther than is necessary, removing every last vestige of anything that wasn't part of a stripped & simple 1960s era engine.
In my opinion, that "desmog guide" does such a disservice to the poor soul who follows it. Way more stuff is removed than is necessary and usually to the detriment of engine performance.

There's only 3 smog components that alter the engine performance negatively: the EGR valve, the Air Pump (very marginally) and the catalytic converter.

The EGR can be disabled just by plugging a vacuum hose (then getting the distributor recurved). The Air Pump can be swapped with an idler pulley, and the cat (if you dare) can be swapped with a straight pipe.

Of those 3 things, the greatest performance improvement will be deleting the cat, with the EGR plug following a close second.
Removing the air pump really isn't noticeable, but it takes up a lot of space and creates a lot of clutter.
Removing anything else makes the engine worse.

So where do I go from here? All that stuff is no longer on my truck. I’m assuming I have a vacuum leak, or misplaced hose somewhere which is why I have low vacuum.

 

[g-man]

here you go, connects to the right of the green plug

 

[g-man]

Once you hook it up ...listen for vacuum leaks on the other side of the engine at the firewall or coming off a loose hose.
Did you say you have no (edit) charcoal canister? See if you can plug and unplug the vacuum lines and tell where this is pulling vacuum.

 

[dannyvp]

I don’t have that port on this new carb.
I have the port on the front shown plugged with a red cap and a port on the back that is attached.

What is the vacuum canister?

 

[dannyvp]

The vacuum is coming out of the top of the carburetor. Is that normal? I cant hear any other leaks over that one. If you put your hand over it, it will suck your hand to it.

 

[g-man]

Yes that big round hole at the top is usually called the horn. Then there is a choke plate and beyond that venturi's and fuel squirts down and the throttle plates at the bottom. Vacuum is being pulled by the pistons and through the intake manifold, up from the intake and pulls gas/air mix down the carb. If you have the air cleaner off the top and put your hand over it the horn you are in essence choking the air getting pulled into the carb.

 

[g-man]

Interestingly this is why at open throttle there is less vacuum on the manifold. The more you open the throttle plates the more air gets pulled thru the carb and the less vacuum pressure there is inside the manifold and any other vacuum lines coming off the manifold.
Engineers took advantage of this when they made a vacuum modulator for automatic transmissions. It varies opening and closing a hydraulic valve in the transmission valve body based on engine vacuum.

 

[dannyvp]

I sprayed carb cleaner at every spot I can find and the engine never rev'ed up.

I did unplug that red stopper on the carb shown above and the vacuum improved, but it went up to around 15 vrs the 11 its running around now.

 

[dannyvp]

Everything gloom right?
Drivers side.

 

[dannyvp]

Everything look right?
Passenger side.

 

[g-man]

No. It's wrong. the vacuum line on the outer port of the dizzy vacuum advance is for HAC system and goes to the vacuum line hard line behind the t-stat the one that has a small vcv on it. It should not be going to the vacuum charcoal canister. The vacuum canister hose that goes there ( the middle port on the canister) is hooked to the hard line on the firewall but I can't see what if anything it is attached to on the other end...you are zoomed in too much. Come out and video 1/2 the engine bay and pan around slower.

 

[g-man]

The second line you put your hand on...the inner port of the dizzy vacuum advance is going over the valve cover and under the air cleaner ...it should hook to the advancer port on the carb pictured here:

 

[g-man]

Here is what your canister line should look like: