Vacuum advance

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whiteblur
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Vacuum advance

Post by whiteblur »

On my inline 6, it seems to run better when i take the vacuum advance line off the carb. hookup spot and leave the line laying on the valve cover. Is this normal or what?
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Re: Vacuum advance

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whiteblur wrote:On my inline 6, it seems to run better when i take the vacuum advance line off the carb. hookup spot and leave the line laying on the valve cover. Is this normal or what?
Nope, sounds like your vacuum advance canister is ruptured which, when connected, is causing a vacuum leak when it's hooked up.

Test your vacuum advance canister with a vacuum pump first before you replace it.
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Re: Vacuum advance

Post by fordman »

:yt:
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Re: Vacuum advance

Post by whiteblur »

how much vacuum should it have/ pull?
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Re: Vacuum advance

Post by whiteblur »

test it on or off the distributor?
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Re: Vacuum advance

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Leave it on the distributor. If you don't have a vacuum pump tester, get one from Harbor Freight for under $20.00. One of the BEST tools a guy can have for diagnostics on an engine. What's an engine? One Big Air Pump!
1970, 2WD, F-250, C/S, Dual Tanks, 390 FE (of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Sky View Blue, Ranger XLT

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"One of the greatest discoveries a man makes, one of his great surprises, is to find he can do what he was afraid he couldn't do" - Henry Ford

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Re: Vacuum advance

Post by fordman »

remove the cap. watch the arm inside of the dist. suck on the hose . if the linkage inside the dist moves then it is good. if it doesnt move then its bad. if you have to suck real hard to make it move then it is bad also.
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Re: Vacuum advance

Post by whiteblur »

why should i replace it if my truck runs good without it hooked up lol :? just wondering
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Re: Vacuum advance

Post by forrestbump »

You'll loose economy at idle and highway speeds when your vacuum advance is pulling at higher levels due to a higher vacuum signal from your motor. The only time your mechanical advance pulls advance is through enertia, when your dizzy is spinning faster when your motor's vacuum signal is lower, when you're giving it gas.

Your motor will also be sluggish when you transition from idle to partial or full throttle and back down. Vacuum advance smooths out this transition.
1970, 2WD, F-250, C/S, Dual Tanks, 390 FE (of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Sky View Blue, Ranger XLT

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Re: Vacuum advance

Post by whiteblur »

sorry but could re explain? some of it i dont understand.....it doesnt do bad at all idling and reving up. tomorrow ill get to drive it for the first time in months
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Re: Vacuum advance

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Your engine will perform much better with than without vacuum advance is the simplest way I can it explain it to you.

Check your vacuum advance canister with a vacuum pump or simply remove the dizzy cap and suck on the rubber hose attached to the vacuum canister and watch for movement...does it pull and push? If NOT, replace it with a new one and I'll bet you'll see a big improvement in your motors performance...trust me.

Think of it this way, if vacuum advance was NOT needed, would Ford (or all other auto companies) engineer, manufacture and install them from the factory? Nope, because it would save them money to NOT have to!
1970, 2WD, F-250, C/S, Dual Tanks, 390 FE (of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Sky View Blue, Ranger XLT

1970, 2WD, F-250, C/S, A/C, Dual Tanks, 390 FE (again, of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Wimbledon White & Sky View Blue, Ranger (almost twin brothers!)

"One of the greatest discoveries a man makes, one of his great surprises, is to find he can do what he was afraid he couldn't do" - Henry Ford

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Re: Vacuum advance

Post by whiteblur »

okay i wont know till tomorrow if it works or not but the hole in the carb for the vacuum advance is hooked to the canister and there is a second hole on the base of the carb that is open with no plug on it, whats that for? when i cover it my engine dies.....
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Re: Vacuum advance

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Ah Ha!!! Sounds like you've discovered a MAJOR vacuum leak. Get a rubber plug and plug it closed. Engine off adjust your carb, the two screws at the base of your carb, turn them all the way in, closing them, then back them out about 1-1/2 turns and fire it up and see if that helps. You'll also have to adjust your idle speed as well.

My guess is your vacuum advance line is connected to the ported vacuum tube, I've followed Woods' advice and connected mine to the direct port, readjusted my carb and admit it's running much better.
1970, 2WD, F-250, C/S, Dual Tanks, 390 FE (of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Sky View Blue, Ranger XLT

1970, 2WD, F-250, C/S, A/C, Dual Tanks, 390 FE (again, of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Wimbledon White & Sky View Blue, Ranger (almost twin brothers!)

"One of the greatest discoveries a man makes, one of his great surprises, is to find he can do what he was afraid he couldn't do" - Henry Ford

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Re: Vacuum advance

Post by whiteblur »

so whats the other port for? and on my truck i just installed power brakes and on my intake i have a big vacuum hole and a small one. right now the PcV is connected to the big one. what will i connect the booster hose to? un hook the big Pcv on and put the booster one there? then where will my pcv hose go?
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Re: Vacuum advance

Post by fordman »

yes the dist is suppose to hook to tstraight manifold vacuum. not ported vacuum. i would switch the dist vacumm line ot he frotn lower tube. and then see how it runs. it can be adjusted to run better thna it is now hooked up correctly.
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