[63 Falcon with a 350]

I don't know hwere to hook the vacuum advance tube form the distributor. I have a 1965 Ford Galaxie 500XL with a 390 Big Block with the stock 4 brl. carb.
Help me out and let me know how to fix this cause when I floor her she'll die if I don't play with the gas pedal.

[docvette]

Doc here,

Two places you can hook the the advance hose..

One is on the Carb to a ported source (It's probably open, or unused) On a Ford I have no Idea what port that might be, on a GM Qjet it's located on the right rear, and left front ...

The other, and better, if you plan on rodding it a bit..is any manifold vacuum source , EXCEPT PCV valve or BRAKE booster.. all other straight vacuum sources are OK.

I have a feeling this is not your whole problem though...you may find you have primary pump issues or mis~adjusted Floats..or even a dieing fuel pump..on back to basics..a clogged Fuel filter.

Small steps though..get the advance hooked up first.

Doc

[Jmark]

Sounds more like the accelerator pump may be bad.

With the advance hooked to EITHER source, when you mash the pedal to the floor, the advance is doing nothing because there is no vacuum signal to it.
Mark

[docvette]

Originally Posted by Jmark

Sounds more like the accelerator pump may be bad.

With the advance hooked to EITHER source, when you mash the pedal to the floor, the advance is doing nothing because there is no vacuum signal to it.
Mark

Doc here,

Mark,

Yeah, that's kinda what I was thinking too... that or a fuel filter...


Doc

[KULTULZ]

Originally Posted by Jmark

With the advance hooked to EITHER source, when you mash the pedal to the floor, the advance is doing nothing because there is no vacuum signal to it.

You are completely sure of this statement?

[KULTULZ]

Originally Posted by 63 Falcon with a 350

I don't know hwere to hook the vacuum advance tube form the distributor. I have a 1965 Ford Galaxie 500XL with a 390 Big Block with the stock 4 brl. carb.

Is your vacuum tubing metal or rubber hose? If steel tubing, the hookup point should be obvious. If rubber tubing, the ported vacuum signal source should be a small metal tube usually located at the choke housing (right side) or slightly before it (towards front of carburetor).

The ported vacuum source will be located above the thottle plates and manifold vacuum source will be located below the throttle plates (if equipped with two signal sources).

Verify vacuum cannister operation with timing light afterwards.

[xntrik]

Originally Posted by Jmark

Sounds more like the accelerator pump may be bad.

With the advance hooked to EITHER source, when you mash the pedal to the floor, the advance is doing nothing because there is no vacuum signal to it.
Mark

*******
YES Duke, I agree with Mark.

Vacuum advance speeds up the timing when there IS vacuum. When you hit wide open throttle there is almost zero vacuum..... so no vac advance timing.
Hook hose to ported vacuum.

1) Accelerator pump squirt = too little, too much, poorly timed (sounds too lean by what you say)

2) OR how about carburetor secondaries popping open too soon.. It's the stock 4 bbl. If its popping open too soon, richening the acc pump won't help the problem.

3) does that thing have a carb power valve?

[KULTULZ]

Originally Posted by xntrik

YES Duke, I agree with Mark.

OK...

Vacuum advance speeds up the timing when there IS vacuum.

When you hit wide open throttle there is almost zero vacuum..... so no vac advance timing.

So you are basically saying that when the throttle blades are completely opened at either start or while cruising, there is an immediate no manifold vacuum condition? How does only the centrifugal advance keep the engine from bogging then if it's curve is set for limited advance throughout the RPM scale (to operate in conjunction with the vacuum advance rate)? If one deletes (or is defective) the vacuum advance of a distributor, the curve has to be modified on the centrifugal side.

If the car bogs at WOT and the vacuum advance is fully operational (vacuum signal-vacuum cannister-breaker plates) then it (bog) can be traced to the accelerator pump or the vacuum secondarys dumping too soon.

[xntrik]

Originally Posted by KULTULZ

OK...



So you are basically saying that when the throttle blades are completely opened at either start or while cruising, there is an immediate no manifold vacuum condition? How does only the centrifugal advance keep the engine from bogging then if it's curve is set for limited advance throughout the RPM scale (to operate in conjunction with the vacuum advance rate)? If one deletes (or is defective) the vacuum advance of a distributor, the curve has to be modified on the centrifugal side.

If the car bogs at WOT and the vacuum advance is fully operational (vacuum signal-vacuum cannister-breaker plates) then it (bog) can be traced to the accelerator pump or the vacuum secondarys dumping too soon.

Manifold vacuum is the RESTRICTION to airflow, not the presence of it. That is why there is vacuum with the throttle closed and almost zero vacuum when the throttle is wide open, regardless of rpm.

Hook up 2 vacuum gauges. One to manifold vacuum and one to ported vacuum and go drive the car and watch them.

Compare to a diesel which has zero vacuum all the time....

I suggest you read up on vacuum, vacuum advance cans, and what distributor advance curves are, and how they work together.

[KULTULZ]

Originally Posted by xntrik

I suggest you read up on vacuum, vacuum advance cans, and what distributor advance curves are, and how they work together.

And I respectfully suggest that you in turn study how manifold and ported vacuum is used to properly operate a vacuum assist distributor...

Mercury-Edsel-Lincoln


-Divisions of CONTINENTAL

-MEL Engine Forum-

[cuda66273]

I suggest he go here and order this book so he'll understand better how all this stuff works together:

http://www.4secondsflat.com/Demon_Tuning_Guide.html

[xntrik]

Originally Posted by KULTULZ

And I respectfully suggest that you in turn study how manifold and ported vacuum is used to properly operate a vacuum assist distributor...

Mercury-Edsel-Lincoln


-Divisions of CONTINENTAL

-MEL Engine Forum-

*********

Duke and Cuda
Respectfully, we might be mixing our terms:
Let me explain further=

some factory engines used manifold vacuum for the cans... but generally you are corrrect in stating that the ported vacuum is to be used...

straight manifold vacuum to the can works sometimes on BIG camshafts to help the engine idle better. Adds a lot of timing at "idle"... but it does take a special can if idle vacuum is very low. (more in a moment)

Vacuum is the pistons sucking against the throttle blades. More when they are closed, less when they are open... (restriction to air flow) Too small a carb might pull 5 inches vacuum at wide open max rpm...

Diesels don't have throttle blades, just a big open hole (they are controlled by fuel injection) and a normally aspirated diesel will read zero vacuum all the time. That is why they all have mechanical vacuum pumps on them to run the vacuum accessories in the car.

Ever heard of a runaway diesel? where the fuel injection just lets her rev up. That is why some diesels have a manual valve to close off airflow to prevent runaways or manual fuel shut off.

If you watch those vacuum gauges on a gas engine,
1) manifold has vac at idle, ported does not= it is above the blades
2) off idle and midrange, both ports read the same vacuum
3) at wide open throttle higher rpm neither has significant vacuum, usually 2 or less. Depending on carb size.

4) zero on a vacuum gauge is ambient atmospheric pressure regardless of altitude.
5) boost is .... pressure (blower, turbo, etc) .... above atmospheric pressure.

6) vacuum (sucking) is less than atmospheric pressure. We can either say the pistons are sucking air in, or the atmosphere is pushing air into the lesser pressure area, the manifold/cylinders.

Duke, the centrifugal advance curve is modified to be more agressive to help that lazy lower rpm full throttle acceleration when there is no vacuum advance happening. Lighter springs, heavier weights, faster idle timing, etc. All contributes to more total timing at any given condition. That's the reason we have always done it. right? And when we do, the vac cans usually make it ping. That's the reason for the adjustable aftermarket cans = to reduce the total degrees (read on) That is the reason that 289 HIPO cars didn't have cans at all.

Generally speaking (numbers)
1) vacuum cans don't start advancing timing until more than about 6 inches of vacuum (6-29) and the AMOUNT in degrees of timing advance is proportional to how hard the vacuum is sucking against the spring in the can. Bigger vac number = More suck = more degrees.

Like valve springs, the coil springs in the cans get tighter as they compress and need more suck to move the timing. (rate of advance)
This is necessary if a car is lugging going up a hill to keep it from pinging, the reducing vacuum is reducing the advance amount. With lower compression engines of the 70s, often backing off the full throttle made the car accelerate faster.... (too slow centrifugal advance curve) think smog.. not power.

example: at 6 in vac there might be zero advance/ at 12 in vac maybe 6 degrees advance/ at 20 in vac maybe 9/ at 28 in vac maybe 14. Advance proportional to throttle position and load, depending on the can spring.

2) most aftermarket vac cans with the allen screw in the hose fitting are adjustable for max degrees of timing only. The RATE of advance is fixed... (the vacuum pulling against the spring in the can.)

3) most factory cans are fixed position. non adjustable, period.

4) 60-70s Fords with the big hex on the front of the vac can are adjustable for max degrees timing, rate of advance, and beginning of advance. easily tuneable with washers and spring change.// The distributor is also factory internally adjustable for centrifugal advance rate and amount. That is why there weren't advance kits for Fords.

Example:
If on a dyno an engine likes 36* total for best power above 3000 rpm,

1) idle timing is 12*
2) centrifugal starts at 1000 rpm and is 24* total at 3000 rpm (that would be 36* total)

at 2000 rpm centrifugal might only be 12* plus the idle 12* = 24* total. With maybe 12 inches of vacuum. then the vac can puts in another 6* for a 30* total. Engine can't stand 36 at 2000 rpm, it will ping.... only above 3000.

3) Romping the throttle to below 6 inches vac drops the vac advance to zero degrees... mechanical total now 24 again. Here's where we want our timing curve modified, but not enough to ping.

As the engine revs up the centrifugal advances to max at 3000.
When we get up 3000 plus and 36* and get off the throttle, the amount of vacuum kicks in more advance, maybe now 42* total, which the engine can stand without pinging under its partial load condition. If not, we have to back off the vacumm degrees.

Also over the years it was discovered that the top gear pull at the drags could be increased by REDUCING the total timing in top gear. Fuel injection cars do this automatically today. Aftermarket timing boxes do it. That is one of the reasons that today's fuelie cars seem to run so strong on the top end for their seemingly limited cubes. Computers read all the parameters and optimize them across the board.

I guess I better stop. Hope this helps clarify.
Oh ya, I got a Sun Distributor machine in 73 I think. Today, if people don't chassis dyno, they just guesstimate and go. Of course there is a lot of experience information out there that lets us guess better.
Thanks,
x

Oh ya, that article that appeared in a national car magazine a few months ago about distributor advance... that guy is grossly mistaken. The only thing worse than not knowing, is infecting everyone else with misinformation. Ever had someone come up to you and shove a magazine in your face to prove you are wrong. I just let them go do what is says, then later they go find somebody else to fix their ride.

[KULTULZ]

Originally Posted by xntrik

*********

Still snowing up there?

Duke and Cuda

Respectfully, we might be mixing our terms:

I don't really think so...

some factory engines used manifold vacuum for the cans... but generally you are corrrect in stating that the ported vacuum is to be used...

Why thank you! Do I get a star?

That's the reason for the adjustable aftermarket cans = to reduce the total degrees (read on) That is the reason that 289 HIPO cars didn't have cans at all.

Adjustible vacuum cannisters are mainly for fine tuning at cruise. Without the vacuum advance feature, fuel economy is hurt. As for the 289/271, that was released as a competition engine and there was little concern for driveabilty and fuel economy.

Generally speaking (numbers)
1) vacuum cans don't start advancing timing until more than about 6 inches of vacuum (6-29) and the AMOUNT in degrees of timing advance is proportional to how hard the vacuum is sucking against the spring in the can.

You have me confused again. If the cannister is not activated until 6in, how does the engine forego tip-in hesitation without a fully centrifigul actuated distributor?

Also over the years it was discovered that the top gear pull at the drags could be increased by REDUCING the total timing in top gear.

Yeah, those guys running giggle gas and blowers really appreciated that discovery.

Oh ya, that article that appeared in a national car magazine a few months ago about distributor advance... that guy is grossly mistaken. The only thing worse than not knowing, is infecting everyone else with misinformation.

Well, I'll tell 'ya. I learn something everyday. When new technology comes along, I like to listen. If it is blowing hot air, I choose not to listen. Can you post this article?

Oh! BTW...What about the systems that use both manifold and ported vacuum?

[dmorris1200]

Man Drooltulz, even after all these years on this board you have nothing better to do than argue your stupid arguments. I guess the meds aren't working. Amazing a guy mentions about a hesitation when flooring from a stop with some relief provided by fluttering the gas peddle (extra accelerator pump shots). More than one person points out the obvious that he may have an accelerator pump adjustment issue or something else besides the vacuum advance causing his hesitation and you start attacking people like the dork that you are. Almost everything others have stated are true...

I have a feeling this is not your whole problem though...you may find you have primary pump issues or mis~adjusted Floats..or even a dieing fuel pump..on back to basics..a clogged Fuel filter.

Sounds more like the accelerator pump may be bad.

and I won't even bother quoting xntrick cause it's too long and almost all good stuff.

Xntrick I like what you have to say because you provide the exact tests to prove what you are saying is essentially correct. Even down to the amount of vacuum needed to move the diaphragm in most vacuum cans.

1. At wide open throttle from a stop my vacuum advance is basically doing squat. It's main purpose is to provide additional advance during light load conditions for additional power without stepping quite as hard on the go peddle and for added fuel economy.
2. I believe that at wide open throttle from a stop proper carb adjustment and centrifugal advance are your two key factors in launching correctly. I have disconnected my vacuum advance and noticed no difference at all pounding her from a stop, only slightly more sluggish during light acceleration.

Here are also two links which pretty much say the same thing as well that vacuum advance plays a minimal role in WOT acceleration.

Ignition timing

Team Camaro


It's a shame you are still hijacking threads . So much for you blaming all your problems on me years back cause it still looks like the same old Drooltulz bull to me.

[xntrik]

Well, Hijack is a strong word. but sort of correct, except for INTENT.

The conversation just headed that way, and since we are all here to share and help each other, we just went on with the current conversation. If we moved this to another thread, it might have gotten lost.

I personally appreciate all the input from Duke, Jessie, cuda, doc, J, 1200, etc.

Sometimes the input on some threads is rather.... ah...... seeminly antagonistic..... the Ford/Chevy/Mopar war gets out of hand sarcasticly....
goes past good fun into deliberate meanness.

One thing I have learned in the last 50 years is that nobody knows it all...
nobody remembers it all correctly.... and

the 60's cars keep getting faster in our memories..... LOL.

Last weekend I saw a SRT4 Dodge front-driver kick a 98 Z-28 Camaro's *** bad on the eighth. And that Camaro was kicking Mustang ***.... yikes, the modern hot rod !!!!!!

"Whoever angers you, controls you."

"Snow on the roof, but still a hot fire in the furnace."
Smile. Life is shorter than you think.
x