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Old 11-26-2008, 09:51 AM
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Gas in dist vac can??

I have my dist out to shim the shaft and when I turned it on its side there was liquid came out of the vac can (gas I think,but little oiliy) can't figure this one out ,it was connected to full manifold vacuum,how could anything go back into the can when vacuum is pulling the other way????

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Old 11-26-2008, 10:50 AM
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Quote:
Originally Posted by yragat
I have my dist out to shim the shaft and when I turned it on its side there was liquid came out of the vac can (gas I think,but little oiliy) can't figure this one out ,it was connected to full manifold vacuum,how could anything go back into the can when vacuum is pulling the other way????
Not uncommon, Ford felt it was an issue for many years so they bent an upward half loop as a trap to stop fuel from percolating back to the vacuum cannister. They were the only people who felt this was enough of an issue to do something.

Bogie
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Old 11-26-2008, 10:53 AM
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so I'm taking it that it's nothinh to worry about
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Old 11-26-2008, 11:42 AM
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"if" it is in good shape:
it's gasoline vapors in the unit that condensated back to liquid when the motor cooled down....

vac unit never gets hot enough to turn it back into vapors....

so it accumulates more and more over time....

do a leak down test on the unit with a "Mighty Vac" to be sure the unit itself is not leaking,,,to prove the bladder and housing are still sealing
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Old 11-27-2008, 12:29 AM
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Mine did this same thing. I`ve run holley`s, edelbrocks, Quadrajets, it didn`t happen with any of these carbs, it only happened when I ran a road demon jr. Not saying only they do so, as I have heard of other carbs doing so as well.
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Old 11-27-2008, 07:56 AM
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I'm Running A Holley--anyone Know How It Can Be Prevented
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Old 11-28-2008, 11:07 AM
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costs to much to truly "prevent it"....
requires a second vacuum canister bladder valve designed to be mounted vertical at the carb so any liquid does flow back into the manifold....
(isolates the dist vac unit itself to operate only with air as in industrial applications that deal with nasty gases)
it has to be engineered to maintain the exact same dist bladder movement per Hg....

best "fix" is install a proper size hose clamp at the dist hose connect...
just a ever so tiny tiny tiny air leak at that point will siphon gas from the manifold to the vac unit...

disconnect the vac at the dist when you get home with the motor hot and atleast the "volatile" liquids will evaporate....

"if" the carb connect is higher than the vac connect:
won't hurt/might help to put a tubing loop at the dist taller than the carb vac connect point....
so that you can periodically pull the hose at the dist to suck back what has accummulated in the now lower tube section collection point...
because the "root" cause is your mega rumpity rumipity low Hg cam duration....
the bottem of the carb and intake are way too wet for way to much of the time (and cold weather makes it worse) so it is accumulating more way faster than normal....

Last edited by red65mustang; 11-28-2008 at 11:16 AM.
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Old 11-28-2008, 11:53 AM
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due to the fact that I have a 1" spacer under the carb,the vac can is lower than the vac conection at the carb,maybe I'll try the loop thing,although I don't know if I'll like the looks of it.
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Old 11-28-2008, 02:45 PM
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forgot to post:

add a clamp at the carb connect as well as at the dist connect...
any leak at that point is pulling vapors towards the hose

the goal is to keep the same column of air in the tubing and unit forever....
that makes it very hard for vapors to "migrate" to the unit

fair to darn good chance that just 2 clamps will eliminate 80%+ of the problem if the mighty vac test shows no leakage...
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Old 11-28-2008, 02:57 PM
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Quote:
Originally Posted by red65mustang
forgot to post:

add a clamp at the carb connect as well as at the dist connect...
any leak at that point is pulling vapors towards the hose

the goal is to keep the same column of air in the tubing and unit forever....
that makes it very hard for vapors to "migrate" to the unit

fair to darn good chance that just 2 clamps will eliminate 80%+ of the problem if the mighty vac test shows no leakage...
You beat me to it.

Either a bad vacuum advance, or connection will cause this.
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Old 11-28-2008, 03:24 PM
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Now wait a minute , your telling me to put clamps on the ends of the hose,but you also told me to dissconect the hose when I park the car???
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Old 11-28-2008, 03:27 PM
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Spelled out the way he intended, it reads 'distributor connection'.

You will need to put a loop, preferably as close to the carburetor as you can, 2" to 2 1/2" at most. This will be better than closer to the distributor, which will require a higher loop.

This should solve your problem.

Just vacuum test your advance unit, to make sure no damage has been done to the diaphragm.

Last edited by carsavvycook; 11-28-2008 at 03:40 PM. Reason: rewording
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Old 11-28-2008, 03:30 PM
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disconnect the vac at the dist when you get home with the motor hot and atleast the "volatile" liquids will evaporate....


add a clamp at the carb connect as well as at the dist connect...
any leak at that point is pulling vapors towards the hose

??????
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Old 11-28-2008, 04:50 PM
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a pic will help????

clamp at the carb and clamp at the dist....

loosen the clamp at the dist to remove the hose to let the vac unit dry out some every once and awhile....

LOL I'm such a nut for NO Hg loss period is why I have clamps on mine....
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Old 11-28-2008, 05:08 PM
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So,like how often do U take the hose off? Wonder if anyone makes a little in-line valve that U could open?
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