The Ford Barn

Bob Bidonde · 04-22-2025, 02:37 PM

For your info, I just finished connecting a vacuum gauge to the windshield wiper fitting on the firewall of my Victoria. Idling at 160F, the gauge reads 22 InHG which is an excellent reading. The engine is a Model B with a 6:1 compression cylinder head, stock Model B camshaft and a Model A Zenith 2 carburetor. This engine has approximately 2500 miles on it since it was completely rebuilt. The vacuum gauge is a 2" diameter unit made by Auto Gage and it will stay in the car.
I do not use the stock windshield wiper, and this year the stock wiper motor will be replaced by an electric unit.

nkaminar · 04-22-2025, 04:43 PM

Indeed 22 inches of Hg is good. Air pressure at sea level is 29.92 inches of Hg. That is a good gauge to keep in the car. You can use it to diagnose troubles and feather the engine for good mileage.

Y-Blockhead · 04-22-2025, 06:19 PM

Caution! This is where the last discussion on Vacuum gauges ended...

https://www.fordbarn.com/forum/showt...+Minder&page=2

Gene F · 04-22-2025, 06:35 PM

Electric wipers are the way to go. Not just on an A, but even later cars.

Joe K · 04-22-2025, 07:49 PM

When Dad owned his 29 RPU, the car had a vacuum wiper.

He was 18-20 at the time and had discovered "smoking." He would regale his friend on how his truck was "smoking hot" and using the rubber vacuum hose on the mouth end of the cigarette (no filter) and it would "burn it right down" in about 20 seconds.

"Waste of a good cigarette" his friend's reply.

Joe K

Y-Blockhead · 04-22-2025, 08:23 PM

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Quote:

Originally Posted by Gene F

Electric wipers are the way to go. Not just on an A, but even later cars.

My '55 Ford Ranchwagon had vacuum wipers. What a PITA with the "dual action" fuel pump to provide enough vacuum on acceleration. It has electric now

nkaminar · 04-23-2025, 07:04 AM

The vacuum windshield wipers are a form of vacuum gauge. Step on the gas and they slow down or stop. Let up on the throttle going down a grade and they fly back and forth at an impossible speed. (Early variable speed wipers?). I used to enjoy using them on a car that I had years ago. I was intrigued by the technology.

noboD · 04-24-2025, 07:05 AM

A friend owned a '24 Buick that had been Professionally rebuilt but never ran correctly for many years. He bought it and wanted to fix it. I put a vacuum gauge on it and it showed retarded cam timing. He was positive I was wrong as he knew the rebuilder. Months later he pulled the cover of and HE discovered the cam was off 3 teeth. I am a believer in what the gauge says.

Bob Bidonde · 04-24-2025, 09:06 AM

Yesterday I made a 24 mile run cruising at 50 MPH. While cruising at a steady speed, the manifold vacuum was steady at about 17 InHG. The slightest change in the throttle drops the manifold vacuum near zero. This sensitivity is due to the small (undersized) CFM of the Zenith carburetor. That is to say, it takes a large throttle change to accelerate the Model "A".

04-22-2025, 02:37 PM	#1
Bob Bidonde Senior Member Join Date: May 2010 Location: Long Island, NY Posts: 4,114	Manifold Vacuum For your info, I just finished connecting a vacuum gauge to the windshield wiper fitting on the firewall of my Victoria. Idling at 160F, the gauge reads 22 InHG which is an excellent reading. The engine is a Model B with a 6:1 compression cylinder head, stock Model B camshaft and a Model A Zenith 2 carburetor. This engine has approximately 2500 miles on it since it was completely rebuilt. The vacuum gauge is a 2" diameter unit made by Auto Gage and it will stay in the car. I do not use the stock windshield wiper, and this year the stock wiper motor will be replaced by an electric unit. __________________ Bob Bidonde

04-22-2025, 04:43 PM	#2
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,874	Re: Manifold Vacuum Indeed 22 inches of Hg is good. Air pressure at sea level is 29.92 inches of Hg. That is a good gauge to keep in the car. You can use it to diagnose troubles and feather the engine for good mileage. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

04-22-2025, 06:19 PM	#3
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 6,652	Re: Manifold Vacuum Caution! This is where the last discussion on Vacuum gauges ended... https://www.fordbarn.com/forum/showt...+Minder&page=2

04-22-2025, 06:35 PM	#4
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 2,476	Re: Manifold Vacuum Electric wipers are the way to go. Not just on an A, but even later cars.

04-22-2025, 07:49 PM	#5
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,612	Re: Manifold Vacuum When Dad owned his 29 RPU, the car had a vacuum wiper. He was 18-20 at the time and had discovered "smoking." He would regale his friend on how his truck was "smoking hot" and using the rubber vacuum hose on the mouth end of the cigarette (no filter) and it would "burn it right down" in about 20 seconds. "Waste of a good cigarette" his friend's reply. Joe K __________________ Shudda kept the horse.

04-23-2025, 07:04 AM	#7
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,874	Re: Manifold Vacuum The vacuum windshield wipers are a form of vacuum gauge. Step on the gas and they slow down or stop. Let up on the throttle going down a grade and they fly back and forth at an impossible speed. (Early variable speed wipers?). I used to enjoy using them on a car that I had years ago. I was intrigued by the technology. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

04-24-2025, 07:05 AM	#8
noboD Senior Member Join Date: May 2010 Posts: 371	Re: Manifold Vacuum A friend owned a '24 Buick that had been Professionally rebuilt but never ran correctly for many years. He bought it and wanted to fix it. I put a vacuum gauge on it and it showed retarded cam timing. He was positive I was wrong as he knew the rebuilder. Months later he pulled the cover of and HE discovered the cam was off 3 teeth. I am a believer in what the gauge says.

04-24-2025, 09:06 AM	#9
Bob Bidonde Senior Member Join Date: May 2010 Location: Long Island, NY Posts: 4,114	Re: Manifold Vacuum Yesterday I made a 24 mile run cruising at 50 MPH. While cruising at a steady speed, the manifold vacuum was steady at about 17 InHG. The slightest change in the throttle drops the manifold vacuum near zero. This sensitivity is due to the small (undersized) CFM of the Zenith carburetor. That is to say, it takes a large throttle change to accelerate the Model "A". __________________ Bob Bidonde