The Ford Barn

Tinker · 03-14-2019, 09:55 PM

So that's your car.

I get it, just wondering where your coming from... it is the internet so, I hope you get the answers you need.

https://www.fordbarn.com/forum/showt...5719&showall=1

Ziggster · 03-14-2019, 10:03 PM

Quote:

Originally Posted by JSeery

How the advance works is well understood.

The vacuum component is likewise well understood and not avoided. It is a very simple system, the vacuum operates a brake on the advance plate to hold back the mechanical advance at low manifold vacuum. With modern fuels the adjustment is normally backed-off to the point very little to no braking is used.

Perhaps for some. The book got it wrong. Kinda disappointed in the book actually. No mention of it here.

https://www.diyford.com/build-perfor...athead-engine/

Google searches don't come up with much other than more questions, but I found this to be a good source of info.

https://www.jalopyjournal.com/forum/....798600/page-2

So, if I recondition my helmet dizzy, and run the vacuum signal line to the port on the manifold, that is all that is needed? No mods other than Isky 1007B cam?

Tinker · 03-14-2019, 10:11 PM

Here is a side by side of the vacuum ports. Crab/helmet. Crab vacuum comes from the cover.

Tinker · 03-14-2019, 10:15 PM

Quote:

Originally Posted by Ziggster

https://www.diyford.com/build-perfor...athead-engine/

A 8ab dizzy.

https://www.jalopyjournal.com/forum/....798600/page-2

PV in a holley carb.

So, if I recondition my helmet dizzy, and run the vacuum signal line to the port on the manifold, that is all that is needed? No mods other than Isky 1007B cam?

maybe you can run that port but originally for a helmet the port is run of the intake between 5-6 cyclinder.

Tinker · 03-14-2019, 10:16 PM

On a helmet (underside of intake) Like this...

I had 42 tudor / 59 and ran the crab. I can dig through pictures and find the source, but I suspect someone will beat me to it.

Tinker · 03-14-2019, 10:41 PM

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Okay now after refreshing my brain.

Vacuum in my instance came of that port. It was bango'ed off the orginal wiper vac fitting. I don't have a better picture, sorry.

Added a before and after for posterity (that round fuel regular never did anything, probably more a fire hazzard then anything

). It was probably one of the cleaner cars I owned. Still have that brown coil.

Ziggster · 03-15-2019, 04:28 AM

[QUOTE=Tinker;1736447]On a helmet (underside of intake) Like this...

I had 42 tudor / 59 and ran the crab. I can dig through pictures and find the source, but I suspect someone will beat me to it.

Excellent. Thanks Jess. That is the first time I've seen mention of that. I forgot to mention I'll be installing an earlier Ford original aluminum intake, so I'm curious to see if it has the same port, but won't be picking it up for a couple of weeks.

Quote:

Originally Posted by Tinker

Okay now after refreshing my brain.

Vacuum in my instance came of that port. It was bango'ed off the orginal wiper vac fitting. I don't have a better picture, sorry.

Added a before and after for posterity (that round fuel regular never did anything, probably more a fire hazzard then anything

). It was probably one of the cleaner cars I owned. Still have that brown coil.

Very nice. Thanks for sharing. So much still to learn. Love these old flatheads. I wish I could install one of those Navaro heads, but my budget won't permit it right now. That coil location was another reason for going with the helmet style dizzy.

Ziggster · 03-15-2019, 04:31 AM

Sorry double post. Too early in the morning...

Ziggster · 03-15-2019, 07:56 AM

Kinda going off topic, but this is a real interesting read. All the way back to 1954, but it is very detailed and still very relevant all these decades later as those new to flatheads will likely discover. So, from what I can gather the vacuum signal should ideally come from above the carb throttle butterfly, and the helmet style dizzy really can only advance or retard the spark by 5 degrees based on the vacuum signal which is not ideal compared to "modern" style diaphragm units. Is this correct?

http://reds-headers.com/html/red_s_engine_talk_4.html

Spark Advance Hop-up Trouble Spot

July/Aug 2006

Red turned the clock back and found an article written by Barney Navarro for "Motor Life" February 1954. With Barney's permission we are running the article following to enlighten Flathead hot rodders in 2006 on the subject of Spark Plug Advance. Thank you, Barney.

Motor Life Feb 1954
Spark Advance Hop-up Trouble Spot
By Barney Navarro
Among the mistakes made in hopping up engines, few exceed in number the misapplication of spark advancing principles. The chief source of error is the limited information available on the subject of spark lead. That which is distributed, unfortunately, fails to cover some essential factors and very often is no more than a comment to the effect that fuel charges take a certain amount of time to burn so spark must be advanced enough to compensate for the time lapse.
Well informed engineers wish that the problem really was that simple. Most ignition system purchasers overlook every factor except the amount of spark produced. The wrong system can cause plenty of trouble: plug fouling, poor gas mileage (even though the engine has no tendency to misfire), overheating in slow traffic, and other maladies. Basically, engines require some means of advancing spark timing as rpm increases since the pistons, in effect, try to get ahead of the burning speed of fuel charges. Combustion, witch takes a definite length of time, must occur when pistons are at the top dead center before the start of the downward power stroke. If burning finishes too early, energy is wasted because the resultant pressure rise produces a force opposition to rotation. This is readily apparent when starting an engine that has too much spark lead; it will actually kick back against the starter's efforts. Modern high compression engines, while under full load, audibly indicate spark that is too far advanced by pinging. So the popular method of setting spark timing for maximum horsepower is to set it just below the ping point under full throttle operation. Distributors that employ flyweight governor advance mechanisms use a spark advance curve that conforms to the engine's requirements under full throttle at any point within the rpm range. At low rpm a lesser spark lead is required so the governor advances a small amount. As speed picks up it advances more and more, always conforming to the full throttle full load requirements. On a drag machine, where full throttle and full load conditions are maintained, the flyweight governor is required. But for ordinary driving, which consists mainly of partial throttle operations with Very light loads, it is not enough. Some other means of compensating for varying loads must be provided. The load compensator is necessary because a light fuel mixture burns more slowly than a heavy charge since the concentration is less and flame takes longer to travel from one fuel particle to the other. If the utmost energy is to be obtained from light charges, their burning should be completed at the same point that the heavy charges finish. So if they take longer, the only way to make them finish at the same point is to start them earlier. Consequently, partial throttle partial load operation requires more spark lead at any given speed than is required at full throttle full load. Load compensation is the most commonly achieved by using intake manifold vacuum to actuate a diaphragm. This diaphragm advances and retards the distributor breaker plate and in some cases the whole distributor case. When the engine is operated with Very light throttle pressure, the manifold vacuum is high, so the diaphragm advances the spark timing to produce the most efficient combustion possible. As the throttle is depressed, the vacuum drops of and the diaphragm produces less advance until it reaches a point of being completely ineffective at wide open throttle. Thus the ideal load compensation is always maintained and results in more power from every drop of fuel.
The second most popular method of obtaining load compensation, though further from perfection is that employed in Ford V-8 distributors from 1932 trough 1948. Instead of a diaphragm, there is piston brake actuated by manifold vacuum, The flyweight governor mechanism is equipped with a breaking disk which cancels five degrees of the governor's advance when pressure is brought to bear on its edge. At this edge a spring-loaded piston is located in a small cylinder. The spring is on the side of the piston opposite the disc so it causes the piston to be pushed against the disc. Vacuum is introduced on the spring side to oppose its action and lift the piston off the disc. In action, the high vacuum produced by operation with small throttle openings lifts the piston of the disk, allows the full action of governor weights to take effect and gives the Ford engine five degrees more spark advance. By depressing the throttle further, the manifold vacuum drops off and the spring again pushes the piston against the disc to retard the spark. The flaw in the operation of this mechanism lies in the fact that it is either full on or full off and permits no gradual compensation like the diaphragm.
Ford's latest method of controlling spark advance employees an ingenious system utilizing manifold vacuum and venturi vacuum. With this system the flyweight governor is eliminated and in its place is nothing but a diaphragm. This diaphragm not only advances the spark to conform to rpm changes but is also makes load compensation adjustments. All ´49 through ´54 Ford and Mercury carburetors have in addition to the conventional manifold vacuum takeoff, such as is found in the throttle body of most passenger car carburetors, a connecting venturi vacuum passage. The manifold vacuum, as usual, is obtained from a small port in the throttle body located slightly above the butterfly's closed, position, on the side where the butterfly swings upward to open. When the throttle is closed at idling, the vacuum port does not receive vacuum because it is on the opposite side of the butterfly. As the throttle is opened slightly, this port is uncovered and a vacuum is applied to the distributor diaphragm to advance the spark. If the throttle is fully depressed, the manifold vacuum is destroyed and no advance takes place. As speed increases, however, the venturi vacuum increases gradually and advances the spark to conform to the rpm. Letting up on the throttle increases the manifold vacuum (Provided it isn't let up all the way) and the spark receives load compensation. A balance is always maintained so that the correct amount of spark advance is supplied for all speed and load conditions.
The greatest installation errors center around the misunderstanding of the late Ford distributors. A distressingly large number of mechanics are unaware of the difference between manifold vacuum and venturi vacuum. In fact many attempt to operate Ford and Mercury distributors by connecting the vacuum line to the windshield wiper connection on dual intake manifolds. This sometimes results from a desire to use the old Stromberg carburetors, which are not equipped with vacuum takeoff. So the simple solution seems to connecting the distributor vacuum line to the handiest apparent source of vacuum. Such practice is worse than having no spark control at all for when the engines idles the spark advances fully and retards as throttle is depressed. There is no venturi vacuum available to advance the spark as the speed picks up and it remains retarded until the throttle is let up. So if the old style carburetors are preferred, the stock Ford distributors must be discarded on the late models. However, Stromberg has resumed production of the old 97 and is now fitting it with a venturi vacuum takeoff to make its use feasible. Four throat carburetion installations also have had their share of improper distributors. Early articles in certain publications gave the impression that no vacuum control whatsoever could be tolerated. It wasn't pointed out that the only forbidden type is that of the stock `49 through `54 Ford and Mercury distributor. This caused many to purchase distributors and magnetos that were equipped with flyweight governors only. Such installations get very poor gas mileage, so the car owners blame the four-throat carburetor. Even more irritating, is the tendency for spark plugs to foul. Having no load compensation, the spark is never far enough advanced under partial throttle to fire the fuel mixture charges at the most opportune time. In effect, the engine is being operated with a lower effective compression ratio because burning is completed as the pistons travel down the cylinder bores. And since the plugs never receive a hot flame, soot collects on them. Furthermore, the condition cannot be remedied by using hotter plugs because they will burn up under full throttle operation of flyweight governor distributor with vacuum-operated load compensation device.
In practice, the installation of dual intake manifold on Fords and Mercury's of the '49 trough '54 series should be accompanied by a change in distributors such as prescribed in the preceding paragraph. The addition of two carburetors divides the airflow so only half as much airflows through one carburetor as previously at normal operating speeds. Venturi vacuum is dependent upon the air velocity through the venturi so any reduction in velocity will result in less spark advance. And connecting a line to each venturi vacuum takeoff of a dual set up will not increase the vacuum---such a practice is just a waste of copper tubing. The best advice to keep in mind when purchasing a distributor is not to pinch pennies. An inexpensive unit, if it doesn't do the job correctly, can prove to be the most costly. The best way to avoid mistakes is to study the problems involved and learn enough about them so that you can select a distributor that matches your engine requirements.

JSeery · 03-15-2019, 11:54 AM

"So, from what I can gather the vacuum signal should ideally come from above the carb throttle butterfly"

Believe you are mixing a lot of things up here. This article is about a lot of different types of distributor over a lot of different years, they work differently. The Ford helmet uses manifold vacuum, as is stated in the article.

"The second most popular method of obtaining load compensation, though further from perfection is that employed in Ford V-8 distributors from 1932 trough 1948. Instead of a diaphragm, there is piston brake actuated by manifold vacuum, The flyweight governor mechanism is equipped with a breaking disk which cancels five degrees of the governor's advance when pressure is brought to bear on its edge."

Have to keep straight what year and model distributor you are dealing with, they work very differently! The Bubba references posted above should help. On a helmet distributor you do NOT want the vacuum source from above the carb throttles plates.

Ziggster · 03-15-2019, 12:02 PM

Quote:

Originally Posted by JSeery

"So, from what I can gather the vacuum signal should ideally come from above the carb throttle butterfly"

Believe you are mixing a lot of things up here. This article is about a lot of different types of distributor over a lot of different years, they work differently. The Ford helmet uses manifold vacuum, as is stated in the article.

"The second most popular method of obtaining load compensation, though further from perfection is that employed in Ford V-8 distributors from 1932 trough 1948. Instead of a diaphragm, there is piston brake actuated by manifold vacuum, The flyweight governor mechanism is equipped with a breaking disk which cancels five degrees of the governor's advance when pressure is brought to bear on its edge."

Have to keep straight what year and model distributor you are dealing with, they work very differently! The Bubba references posted above should help.

Yes, in the context here they work differently as I'm discovering. In all the pics I have looked at over many months of flatheads I really haven't seen anything that jumps out regarding a vacuum line running between the intake manifold and dizzy/ cam cover understanding the later engines used an altogether different distributor.

Ziggster · 03-15-2019, 12:11 PM

Actually I stand corrected. Looking back at one of my favourite pics of a flathead I can now barely make out the tube coming off the front cover and making its way to the manifold between cylinders 5 & 6. Thanks again Jess for your help. Much appreciated.

Ziggster · 03-15-2019, 02:30 PM

The engineer in me can now relax. My soon to be mine aluminum head has the necessary vacuum port. Hope everything else matches up.

Seth Swoboda · 03-15-2019, 02:56 PM

I read through this and I'm really confused. You're recreating this car and it will have a 5.0 liter air cooled engine and you're using a flathead Ford "helemet" style distributor?

JSeery · 03-15-2019, 03:24 PM

Quote:

Originally Posted by Seth Swoboda

I read through this and I'm really confused. You're recreating this car and it will have a 5.0 liter air cooled engine and you're using a flathead Ford "helemet" style distributor?

He is attempting to simulate it (the look) using a flathead v8.

Seth Swoboda · 03-15-2019, 04:09 PM

Quote:

Originally Posted by JSeery

He is attempting to simulate it (the look) using a flathead v8.

Gotcha. When he mentioned the 5.0 liter air cooled and helmet distributor, I thought there was going to be some great feat of engineering happening.

Ziggster · 03-18-2019, 07:31 AM

Just for laughs I came across this pic from a recent post on the HAMB. Sure looks like someone plumbed the oil return from the oil filter into the cam cover vacuum port.

rotorwrench · 03-18-2019, 09:03 AM

The oil return on the early head mounted filters drained into the fuel pump/oil filler stand on the back. Later ones drained back into the oil pan. It could drain into the valve train valley area if a person wanted to modify it to do that.

Ziggster · 03-18-2019, 09:40 AM

Quote:

Originally Posted by rotorwrench

The oil return on the early head mounted filters drained into the fuel pump/oil filler stand on the back. Later ones drained back into the oil pan. It could drain into the valve train valley area if a person wanted to modify it to do that.

I guess, but that port on the cam cover also connects to the dizzy assuming it has the same body as the crab style dizzy. If so, wouldn't oil end up in the dizzy? This kinda goes back to the post I made concerning the comment in the book where it states the cam cover port is for oiling.

JSeery · 03-18-2019, 12:50 PM

One version on the oil filter has the return line going the the distributor area. A banjo fitting and hollow bolt are used.

03-14-2019, 09:55 PM	#21
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Switching cam gear cover from 2-bolt to 3-bolt So that's your car. I get it, just wondering where your coming from... it is the internet so, I hope you get the answers you need. https://www.fordbarn.com/forum/showt...5719&showall=1

03-14-2019, 10:16 PM	#25
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Switching cam gear cover from 2-bolt to 3-bolt On a helmet (underside of intake) Like this... I had 42 tudor / 59 and ran the crab. I can dig through pictures and find the source, but I suspect someone will beat me to it. Last edited by Tinker; 03-14-2019 at 10:24 PM.

03-15-2019, 04:31 AM	#28
Ziggster Senior Member Join Date: Aug 2018 Location: Ottawa, ON Posts: 850	Re: Switching cam gear cover from 2-bolt to 3-bolt Sorry double post. Too early in the morning...

03-15-2019, 07:56 AM	#29
Ziggster Senior Member Join Date: Aug 2018 Location: Ottawa, ON Posts: 850	Re: Switching cam gear cover from 2-bolt to 3-bolt Kinda going off topic, but this is a real interesting read. All the way back to 1954, but it is very detailed and still very relevant all these decades later as those new to flatheads will likely discover. So, from what I can gather the vacuum signal should ideally come from above the carb throttle butterfly, and the helmet style dizzy really can only advance or retard the spark by 5 degrees based on the vacuum signal which is not ideal compared to "modern" style diaphragm units. Is this correct? http://reds-headers.com/html/red_s_engine_talk_4.html Spark Advance Hop-up Trouble Spot July/Aug 2006 Red turned the clock back and found an article written by Barney Navarro for "Motor Life" February 1954. With Barney's permission we are running the article following to enlighten Flathead hot rodders in 2006 on the subject of Spark Plug Advance. Thank you, Barney. Motor Life Feb 1954 Spark Advance Hop-up Trouble Spot By Barney Navarro Among the mistakes made in hopping up engines, few exceed in number the misapplication of spark advancing principles. The chief source of error is the limited information available on the subject of spark lead. That which is distributed, unfortunately, fails to cover some essential factors and very often is no more than a comment to the effect that fuel charges take a certain amount of time to burn so spark must be advanced enough to compensate for the time lapse. Well informed engineers wish that the problem really was that simple. Most ignition system purchasers overlook every factor except the amount of spark produced. The wrong system can cause plenty of trouble: plug fouling, poor gas mileage (even though the engine has no tendency to misfire), overheating in slow traffic, and other maladies. Basically, engines require some means of advancing spark timing as rpm increases since the pistons, in effect, try to get ahead of the burning speed of fuel charges. Combustion, witch takes a definite length of time, must occur when pistons are at the top dead center before the start of the downward power stroke. If burning finishes too early, energy is wasted because the resultant pressure rise produces a force opposition to rotation. This is readily apparent when starting an engine that has too much spark lead; it will actually kick back against the starter's efforts. Modern high compression engines, while under full load, audibly indicate spark that is too far advanced by pinging. So the popular method of setting spark timing for maximum horsepower is to set it just below the ping point under full throttle operation. Distributors that employ flyweight governor advance mechanisms use a spark advance curve that conforms to the engine's requirements under full throttle at any point within the rpm range. At low rpm a lesser spark lead is required so the governor advances a small amount. As speed picks up it advances more and more, always conforming to the full throttle full load requirements. On a drag machine, where full throttle and full load conditions are maintained, the flyweight governor is required. But for ordinary driving, which consists mainly of partial throttle operations with Very light loads, it is not enough. Some other means of compensating for varying loads must be provided. The load compensator is necessary because a light fuel mixture burns more slowly than a heavy charge since the concentration is less and flame takes longer to travel from one fuel particle to the other. If the utmost energy is to be obtained from light charges, their burning should be completed at the same point that the heavy charges finish. So if they take longer, the only way to make them finish at the same point is to start them earlier. Consequently, partial throttle partial load operation requires more spark lead at any given speed than is required at full throttle full load. Load compensation is the most commonly achieved by using intake manifold vacuum to actuate a diaphragm. This diaphragm advances and retards the distributor breaker plate and in some cases the whole distributor case. When the engine is operated with Very light throttle pressure, the manifold vacuum is high, so the diaphragm advances the spark timing to produce the most efficient combustion possible. As the throttle is depressed, the vacuum drops of and the diaphragm produces less advance until it reaches a point of being completely ineffective at wide open throttle. Thus the ideal load compensation is always maintained and results in more power from every drop of fuel. The second most popular method of obtaining load compensation, though further from perfection is that employed in Ford V-8 distributors from 1932 trough 1948. Instead of a diaphragm, there is piston brake actuated by manifold vacuum, The flyweight governor mechanism is equipped with a breaking disk which cancels five degrees of the governor's advance when pressure is brought to bear on its edge. At this edge a spring-loaded piston is located in a small cylinder. The spring is on the side of the piston opposite the disc so it causes the piston to be pushed against the disc. Vacuum is introduced on the spring side to oppose its action and lift the piston off the disc. In action, the high vacuum produced by operation with small throttle openings lifts the piston of the disk, allows the full action of governor weights to take effect and gives the Ford engine five degrees more spark advance. By depressing the throttle further, the manifold vacuum drops off and the spring again pushes the piston against the disc to retard the spark. The flaw in the operation of this mechanism lies in the fact that it is either full on or full off and permits no gradual compensation like the diaphragm. Ford's latest method of controlling spark advance employees an ingenious system utilizing manifold vacuum and venturi vacuum. With this system the flyweight governor is eliminated and in its place is nothing but a diaphragm. This diaphragm not only advances the spark to conform to rpm changes but is also makes load compensation adjustments. All ´49 through ´54 Ford and Mercury carburetors have in addition to the conventional manifold vacuum takeoff, such as is found in the throttle body of most passenger car carburetors, a connecting venturi vacuum passage. The manifold vacuum, as usual, is obtained from a small port in the throttle body located slightly above the butterfly's closed, position, on the side where the butterfly swings upward to open. When the throttle is closed at idling, the vacuum port does not receive vacuum because it is on the opposite side of the butterfly. As the throttle is opened slightly, this port is uncovered and a vacuum is applied to the distributor diaphragm to advance the spark. If the throttle is fully depressed, the manifold vacuum is destroyed and no advance takes place. As speed increases, however, the venturi vacuum increases gradually and advances the spark to conform to the rpm. Letting up on the throttle increases the manifold vacuum (Provided it isn't let up all the way) and the spark receives load compensation. A balance is always maintained so that the correct amount of spark advance is supplied for all speed and load conditions. The greatest installation errors center around the misunderstanding of the late Ford distributors. A distressingly large number of mechanics are unaware of the difference between manifold vacuum and venturi vacuum. In fact many attempt to operate Ford and Mercury distributors by connecting the vacuum line to the windshield wiper connection on dual intake manifolds. This sometimes results from a desire to use the old Stromberg carburetors, which are not equipped with vacuum takeoff. So the simple solution seems to connecting the distributor vacuum line to the handiest apparent source of vacuum. Such practice is worse than having no spark control at all for when the engines idles the spark advances fully and retards as throttle is depressed. There is no venturi vacuum available to advance the spark as the speed picks up and it remains retarded until the throttle is let up. So if the old style carburetors are preferred, the stock Ford distributors must be discarded on the late models. However, Stromberg has resumed production of the old 97 and is now fitting it with a venturi vacuum takeoff to make its use feasible. Four throat carburetion installations also have had their share of improper distributors. Early articles in certain publications gave the impression that no vacuum control whatsoever could be tolerated. It wasn't pointed out that the only forbidden type is that of the stock `49 through `54 Ford and Mercury distributor. This caused many to purchase distributors and magnetos that were equipped with flyweight governors only. Such installations get very poor gas mileage, so the car owners blame the four-throat carburetor. Even more irritating, is the tendency for spark plugs to foul. Having no load compensation, the spark is never far enough advanced under partial throttle to fire the fuel mixture charges at the most opportune time. In effect, the engine is being operated with a lower effective compression ratio because burning is completed as the pistons travel down the cylinder bores. And since the plugs never receive a hot flame, soot collects on them. Furthermore, the condition cannot be remedied by using hotter plugs because they will burn up under full throttle operation of flyweight governor distributor with vacuum-operated load compensation device. In practice, the installation of dual intake manifold on Fords and Mercury's of the '49 trough '54 series should be accompanied by a change in distributors such as prescribed in the preceding paragraph. The addition of two carburetors divides the airflow so only half as much airflows through one carburetor as previously at normal operating speeds. Venturi vacuum is dependent upon the air velocity through the venturi so any reduction in velocity will result in less spark advance. And connecting a line to each venturi vacuum takeoff of a dual set up will not increase the vacuum---such a practice is just a waste of copper tubing. The best advice to keep in mind when purchasing a distributor is not to pinch pennies. An inexpensive unit, if it doesn't do the job correctly, can prove to be the most costly. The best way to avoid mistakes is to study the problems involved and learn enough about them so that you can select a distributor that matches your engine requirements.

03-15-2019, 11:54 AM	#30
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: Switching cam gear cover from 2-bolt to 3-bolt "So, from what I can gather the vacuum signal should ideally come from above the carb throttle butterfly" Believe you are mixing a lot of things up here. This article is about a lot of different types of distributor over a lot of different years, they work differently. The Ford helmet uses manifold vacuum, as is stated in the article. "The second most popular method of obtaining load compensation, though further from perfection is that employed in Ford V-8 distributors from 1932 trough 1948. Instead of a diaphragm, there is piston brake actuated by manifold vacuum, The flyweight governor mechanism is equipped with a breaking disk which cancels five degrees of the governor's advance when pressure is brought to bear on its edge." Have to keep straight what year and model distributor you are dealing with, they work very differently! The Bubba references posted above should help. On a helmet distributor you do NOT want the vacuum source from above the carb throttles plates.

03-15-2019, 02:56 PM	#34
Seth Swoboda Senior Member Join Date: May 2010 Location: Southern Illinois Posts: 3,787	Re: Switching cam gear cover from 2-bolt to 3-bolt I read through this and I'm really confused. You're recreating this car and it will have a 5.0 liter air cooled engine and you're using a flathead Ford "helemet" style distributor?

03-18-2019, 09:03 AM	#38
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,425	Re: Switching cam gear cover from 2-bolt to 3-bolt The oil return on the early head mounted filters drained into the fuel pump/oil filler stand on the back. Later ones drained back into the oil pan. It could drain into the valve train valley area if a person wanted to modify it to do that.

03-18-2019, 12:50 PM	#40
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: Switching cam gear cover from 2-bolt to 3-bolt One version on the oil filter has the return line going the the distributor area. A banjo fitting and hollow bolt are used.