Author Topic: Vacuum Line Routing-Effects  (Read 1300 times)

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HarleyJack17

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Vacuum Line Routing-Effects
« on: September 29, 2020, 11:02:16 AM »
It pertains to an FE, and others as well. Just pondering....

The engine compartment on my old truck is "busy" to say the least.  Looking at vacuum lines, I had the hypothetical thought of running one line from the intake and running a distribution block to feed all the items requiring vacuum.   In my instance, we have the C6 modulator line, heater controls, a low vacuum switch.  The intake has a standard OEM large bore T with ports off of it.  Does not make sense to do for only eliminating 2 lines but just thinking on the subject. 
I searched for info on the subject and found nothing.
If doing something such as this what should be taken into account: What effects could be had, and what about line size.  I would assume no effect if you fed the block with the same size line, and kept the sizes the same but found 0 info on the effects of line size on vacuum.
Maybe I am missing something.....I know the "pull" does not change but changes in line size effect volume and wonder the effects of that.  Just seems that there is not much info on it, at least that I found.


Certainly wish there was a way to clean up the wiring and vacuum lines and get them "away" from the motor so you see a nice clean intake/carb and no wiring. Be nice to see some pics as to what others have done in the engine bays to clean it up.  Most all of them run the same...temp, oil, coil, wiring....

RJP

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Re: Vacuum Line Routing-Effects
« Reply #1 on: September 29, 2020, 11:12:10 AM »
Keep the trans vacuum modulator line separate. I strongly advise using a dedicated vacuum port for the modulator and kept away from other vacuum operated items like power brakes, PCV valve and anything else that is vacuum powered.  My preference for the modulator is at the base of the carb, it "sees" vacuum changes instantly and is not as influenced by other vacuum operated items.   

GerryP

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Re: Vacuum Line Routing-Effects
« Reply #2 on: September 29, 2020, 12:09:34 PM »
Other than the transmission modulator mentioned above, sure you can run your system from a manifold.  But it would be better to run your main line to a vacuum reservoir, then run from the reservoir to a distribution block.  The reservoir would serve as a buffer and things like your HVAC controls would work regardless of engine load.  The downside of doing it this way is that if something happens to your system, you lose all the vacuum power.  There are other ways to clean things up.  I bent up hard lines to clean up the runs so that there is hose only where it connects on the ends.  The hard lines are much thinner than hose and don't look like someone just threw them on there.

HarleyJack17

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Re: Vacuum Line Routing-Effects
« Reply #3 on: September 29, 2020, 02:37:43 PM »
Gerry P, I had thought about that as well.  Good idea on the can.....the heat controls route to that first currently.  Really my question was more geared to what happens if you change the size of the line...bigger or smaller. I mean they share vacuum now since ALL connect to one spot on the intake. I just hate spending all the time I have on cleaning up everything and now it has wiring and hoses covering the good stuff if you will.

RJP,
Where on the carb? I only have one port available as it is.  One is for the brakes(at the base/large) and one for the vacuum advance.  There is one remaining port at the front base that I have plugged.  When I got the old truck everything worked fine, so I kept the routing as it was after the engine build.  How great would the effect/change be? I may give that a try once I get it on the road....still a few checks to do and bed to put back on.

RJP

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Re: Vacuum Line Routing-Effects
« Reply #4 on: September 29, 2020, 10:11:30 PM »
If you have the port on the carb's base plate that angles off at at about a 45 deg angle towards the passenger side use that port as it should be connected directly to the manifold vacuum. Don't tree off of that port for other vacuum operated items, leave that as a dedicated trans modulator port. Your modulator should respond exactly to manifold vacuum and not be interfered with by any other vacuum draw.

HarleyJack17

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Re: Vacuum Line Routing-Effects
« Reply #5 on: September 30, 2020, 10:46:52 AM »
That is the port. I will give it a try versus on the T-Tree.  Thank you.  The methodology behind it makes sense. I may end up adding some metal tube into the mix to shorten the rubber parts.  If I can find a good attachment point to make it look more clean it should not be too hard. I think everything else would work fine with 3/16 tubing. The trans line is bigger than those...1/4" it appears. Smaller than the 5/16 I used on the C6 but bigger than the standard brake tubing I have.
« Last Edit: September 30, 2020, 01:33:08 PM by HarleyJack17 »

Riderjeff

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Re: Vacuum Line Routing-Effects
« Reply #6 on: September 30, 2020, 01:10:23 PM »
I believe what you're talking about is a vacuum distributor, and I'm pretty sure there's one under the dash on my '65 T-bird.  It runs all the accessory vacuum applications, door locks, vents, etc.