Vacuum Line Mystery

[The Fez]

After doing some research here as well as Ratwell's site, I decided to tackle the actual routing of vacuum hoses on my 74 Westy between the stock carb and the double advance distributor. The advance vacuum hose was properly attached to the left side of the 32-34 PDSIT carb, but the retard line was a bit of a mystery. For one, it wasn't hooked up to anything. The retard nipple had been blocked off and the hose was 'nearby', but not hooked up to anything (not sure how that happened, but I know I didn't do it).

What is the device to the right of the carb? It appears to have a vacuum nipple well. I wonder if it had been attached here and not the retard port on the carb. Does a Petronix ignition system change things up?

Any sage advice graciously accepted.

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My projects (so far):
74 Westfalia
47 Willys CJ2A

[old DKP driver]

That is the EGR valve port that was connected to the barb on the brake booster
line on the other side of the tin near the top of the transmission.
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V.W.owner since 1967

[Wildthings]

Most retard cans have failed by this point and thus the hoses to them have been plugged to eliminate the vacuum leak this creates. If you retard can is bad, then you should not be setting your timing to the 5 or 10° ATDC spec as your timing will be way too far retarded if you do. Instead set your idle timing at 7.5° BTDC with the advance hose removed, or better yet set you timing at full mechanical advance, 28° BTDC @3500+ rpms hoses removed.

[The Fez]

That's interesting and quite possible. How does one test a retard can to determine if it is bad?
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My projects (so far):
74 Westfalia
47 Willys CJ2A

[Wildthings]

Connect a hose to the can and suck hard on the other end while watching the contact plate to see if it moves. Once it moves stick your tongue over the end of the hose to see that the vacuum does not leak off. You can do the the test with a Mityvac style vacuum pump if you have one.

[Tcash]

Link

[Wildthings]

[airschooled]

I tried to make that video longer but my camera ran out of memory and I said "good enough." There is a special place in hell for people who make a twenty minute video on how to do a four minute job.

Robbie
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Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com

[The Fez]

So with a Petronix electronic ignition setup, the same thing will happen?
_________________
My projects (so far):
74 Westfalia
47 Willys CJ2A

[Tcash]

[The Fez]

Thanks for all the help. I did the amazingly technical suction test on the vacuum unit and it worked beautifully. I'm just down to the dynamic timing and dual carb adjustment and I should have no trouble tackling the hills of the Coquihalla Highway this summer, albeit at a fast snail's pace.
_________________
My projects (so far):
74 Westfalia
47 Willys CJ2A

[Tcash]

Lubing the Distributor

[Wildthings]

For use near sea level, setting your timing at 28° BTDC @ 3500+ rpm's hoses off and plugged is still the best method.