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Discussion Starter #1 (Edited)
Here is a post that I recently put in the classicopels site, and I thought it might be of interest to this list:

Exhaust or Gas Smell in the Interior?

Have you checked the gas line where it connects to the tank, inside
the rubber cover? Sometimes mud collects in there, and the steel
gas line corrodes. Mine had a couple of pinholes, so small that the
gas wouldn't actually drip but seemed to vapourize, causing a gas
smell inside the car. Or does your tank have a hole in it? A
slight drip of gas into the tail will cause a smell like exhaust.

Or could it be improperly sealed tail-lights? When the GT moves
forward, it creates a low pressure area around the Kamm-tail. If
you are missing the tail light gaskets, or of they are not sealing,
you might draw exhaust fumes into the car. There are also bigger
drain hoses inside the rear compartment from the sides of the rear
window that drain down beside the gas tank. They normally have
rubber ends on them that are "pinched" to prevent road dirt and such
from entering. Are the hoses properly conected to the drain tubes?
If you crack a side window when the car is moving, does the smell
subside? How about if you crack a rear quarter window (on post 1970
GT's)? If you pressurize the cabin by turning the fan on to "high",
does the smell go away?

Or, do you have the PCV hoses correctly installed to the valve cover
and manifold, both the small hose and the big hose ? Blowby gas can
smell like exhaust or gas.

Or, do you have the charcoal cannister (in front of the radiator)
hooked up so that it is vented into the carb throat? Many folks who
install a Weber simply dissconnect the cannister, but then the gas
fumes from the tank have nowhere to go but into the air space under
the hood, and then the fumes work their way into the car.


HTH
 

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Discussion Starter #2 (Edited)
What to do With the Cannister Connection With a Weber?

--- In [email protected], Jimsky <[email protected]> wrote:

Just what do people do with this line who have Webers? I think
mine is just hanging out under the hood somewhere by the PO. I'd
like to do something better but never figured out what to do with
this open line. Suggestions?

Jimsky
'73 GT "Katie"


Jim,

The stock Solex has a fitting around the back, next to the valve
cover, connected to a port in the carb throat just ABOVE the
venturi, which is a fairly low pressure area when the engine is at
cruising RPM. This provides a slight vacuum to allow the charcoal
canister to vent into the combustion process, burning the
accumulated vapours.

Since the Weber has no such port, the next best solution is to
connect to the filter case (if you have the typical chrome box
filter on your Weber) DOWNSTREAM, or inside, the filter, so the
pressure drop caused by the air filter provides the required vacuum
to allow the canister to vent into the carb throat. Many of these
filters have a fitting connection in their base, so I installed a
tee, with one side feeding the big hose to the valve cover (which
DOES flow towards the valve cover, but that is a different topic),
and the other side connected to the canister vent. But if you have
adapted the stock GT filter to a Weber, just connect the canister
vent to the breather fitting just before the carb. Don't worry
about the canister vapours going into the valve cover; at an idle,
they are in turn drawn out by the small hose that is connected to
the PCV orifice at the base of the intake manifold and into the
engine where they are burned. Above an idle, the air flow is
towards the carb throat.

Weber carbs also are missing the float bowl vent connection to the
canister that the Solex has, since it is vented directly to the carb
throat. This was to allow the fumes from the bowl to be accumulated
in the cannister when the engine is at an idle. You just have to
block the extra connection on the canister. Which leaves one
connection from the tank to accumulate tank vapours, and a second
connection to the carb as described above.

HTH

Keith Wilford
'71 GT
 

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Discussion Starter #3 (Edited)
Carb Connections to the Charcoal Cannister

Here is a picture of the factory connections to the Solex carb:

 

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So the lower port goes to the gas tank. Then the upper port would go to the air cleaner port on the Weber carb, if I have this right. and the middle port on the canister can be capped off. Is this right?
 

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Opel Rallier since 1977
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It looks to me that it may depend on the year. The 1974 Service manual has the center port for that year's canister connected to the fuel tank. (No GT's in that year.) But a '71 Service manual shows it going to one of the outer (side) ports on a 50 series chassis diagram (Manta and Ascona/1900).

Any chance there is still a tag under the hood on your car, showing all the emissions control connections?
 

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Here is one connection scheme; Kwilford describes another above. The idea is to connect the center port of a 3 port canister to the line from the fuel tank, and a vacuum source flowing into the carb to draw accumulated vapors in the canister to one of the side ports.

Look for a vacuum port on the side below the choke (the side away from the engine). This port will be about 1//2" above the bottom of the carb, and will be 'ported' vacuum. A vacuum gauge attached here will show little or no vacuum at idle but the vacuum level will rise as you open the throttle and rev up the engine. Your vacuum advance to the distributor may connect here too.

Below is a diagram from another application; see the 3rd post in this thread. The red circle shows the ported vacuum port on the Weber. The blue circle shows the optional bowl vent port; the OGTS pix do not show a port here, so presumably their Weber 32/36's don't have this port. This can be omitted and the 2nd outer port on the canister capped off.

There needs to be a venting 'into' the tank somewhere for this all to work.

Edit to add: You may need a restriction in the line from the canister so that the flow will not be excessive. If you hook up to the ported vacuum and the off-idle or light cruise performance changes appreciably, that is a sign that a restriction is needed.

 

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Opeler
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GM OBD I vehicles used vacuum purge valve on some of the fuel vapor canisters, ACDELCO 214-2294. Might be overkill. Price is approx. $30.00 from eBay or RockAuto.

ACDELCO 214-2294.jpg
 

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... But a '71 Service manual shows it going to one of the outer (side) ports on a 50 series chassis diagram (Manta and Ascona/1900).
Any chance there is still a tag under the hood on your car, showing all the emissions control connections?
Yes. See below. Right now I have the bottom port hooked up to the fuel tank, and the top port going to the Weber, and the center port capped off. I would really like to know if this is right, so I can finally put it to bed. It's driving me crazy because there's a different answer in just about every post I read. Will this tag help identify if I've done it up right?
430070
 

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That looks like an ignition timing tag, so, no, not a help.

I have to apologize... I messed you up with my description above, as I read the diagram in the manual wrong. I have revised my prior post above to correct this connection info. The center port of the later 3 port canisters connects to the tank's vent line.

The center port ought to go the tank.... and an outer port to the correct (ported vacuum) port on the Weber. Can you supply a pix of where it connects to the Weber?

And... I referred to maybe needing a restriction for the line from the canister to the ported vacuum. And indeed, the '74 FSM mentions a restriction inside a short hose that attaches between the canister and the line to the carb's ported vacuum, as well as a restriction back at the tank. I'll see if I can get a pix of that illustration.
 

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That looks like an ignition timing tag, so, no, not a help.

I have to apologize... I messed you up with my description above, as I read the diagram in the manual wrong. I have revised my prior post above to correct this connection info. The center port of the later 3 port canisters connects to the tank's vent line.

The center port ought to go the tank.... and an outer port to the correct (ported vacuum) port on the Weber. Can you supply a pix of where it connects to the Weber?

And... I referred to maybe needing a restriction for the line from the canister to the ported vacuum. And indeed, the '74 FSM mentions a restriction inside a short hose that attaches between the canister and the line to the carb's ported vacuum, as well as a restriction back at the tank. I'll see if I can get a pix of that illustration.
I'm using standard fuel line hoses for both canister hookups, so in addition to changing the order of the connections, I also have to have restrictions in the hoses? How should I do that? Here's a pic of the hookups on my Weber:
430071
 

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That is a connection for PCV (positive crankcase ventilation). Where does the hose from the canister to the carb connect to the carb? Does the canister connect to that open thread port that you show? If it connects there, then where does the connection go to the carb? Down under the base of the carb?

Here is the '74 manual pix of the connections of the 3 port canister. See note 5 in this pix about the restriction in the short piece of hose to which tag #5 points. I have never looked to see what that is. It is an assumption on my part that the same 3 port canister was used in earlier years like in your car:
 

Attachments

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Opeler
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$1.24 each plus shipping at RockAuto.
DORMAN 493021 {#47311} 3/16 In. Hard Vacuum Tubing Connector;
Restrictor; Diameter 3/16"
Category: Vacuum Hose Connector


Dorman 439021.jpg

$7.32 each Amazon.
Subaru 22326KA120 Red restrictor Pill Required for Access Port WRX & 07 STi
2175LiD+k3L._AC_.jpg
Approx. $15.00
Subaru Restrictor Pill w/T-Fitting Vacuum 2006 2007 WRX 2006-2008 Forester Genuine

61WuKbYY5RL._AC_SL1500.jpg
 

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That is a connection for PCV (positive crankcase ventilation). Where does the hose from the canister to the carb connect to the carb? Does the canister connect to that open thread port that you show? If it connects there, then where does the connection go to the carb? Down under the base of the carb?

Here is the '74 manual pix of the connections of the 3 port canister. See note 5 in this pix about the restriction in the short piece of hose to which tag #5 points. I have never looked to see what that is. It is an assumption on my part that the same 3 port canister was used in earlier years like in your car:
I have a "T" under the carb going into the air cleaner. One side goes to the large port on the valve cover, and the other one goes to the canister. I now have the fuel tank going into the center canister port, and the bottom port going to the "T". The top port is capped off. In the picture, the dark hose going by the fuel filter and to the front of the car is coming from the carb "T", and going to the canister. I'm going to go with this being the correct hookup, since it makes sense that the middle port is the one where the fuel tank hose goes. I drove it like this today and I did not notice any gas smell, but I still need to address the restrictor issue I suppose.
 

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Here's how it was designed to work with the stock carb or a modified aftermarket weber.
(From March/April 2008 Blitz )
View attachment 429793
If you read the info on this picture, first it tells you that the "Gas Tank: Connected to the center canister port...".
Then in the upper frame (top right) it says "Lower side port to fuel tank...".
Then at the bottom left when referring to the Weber, it says "...either or both the upper and lower canister ports can be capped".
How can anyone make sense of this?
 

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Yes, that certainly seems contradictory!LOL

From your description above, it sounds like that threaded port on your brass tee pictured above goes to the bottom of the air cleaner housing. If so, then it sounds like your connection from the canister into the carb is not complete. There needs to be a canister-to-carb connection to go to a port on the side of the Weber carb (ported vacuum). See the red circled port in the pix in the 3rd post of the Turbobricks article linked above.

I am realizing now that the venting of the fuel tank (as fuel is drawn out) also goes via the canister in some of these canister systems. So that has to be part of all this. So your present connection from the air cleaner to the canister probably needs to stay for that function. And, I guess I am going to have to take one of these apart (after all these years) to see how the 3 hose nipples lead into the charcoal bits.

May I ask: Does the 'other' end of your canister (the end with no hose nipples) have any openings, with a foam or paper filter behind it?
 
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