The Ford Barn

rustythumb · 12-03-2016, 04:47 PM

just bought a '36 with later motor. i noticed it has a small copper tube going from a raised boss on the front cover to a boss on the intake manifold. my other flathead has nothing like that! anyone know what this is for? thanks!

V8COOPMAN · 12-03-2016, 04:57 PM

It's to supply a source for the vacuum brake on the distributor. DD

rustythumb · 12-03-2016, 05:50 PM

on my other motor, the tube goes to the distributor,not to the timing cover. why is this different ?

34PKUP · 12-03-2016, 06:04 PM

Quote:

Originally Posted by rustythumb

on my other motor, the tube goes to the distributor,not to the timing cover. why is this different ?

It's called 'design change'. Just a different route to the same destination.

V8COOPMAN · 12-03-2016, 06:49 PM

Quote:

Originally Posted by rustythumb

on my other motor, the tube goes to the distributor,not to the timing cover. why is this different ?

The 3-hole mount '37-'41 "helmet" distributors have the vacuum line attached to the distributor. The '42 and later "crab-type" two-bolt distributors have the vac line attached to the cam cover. DD

Mart · 12-03-2016, 07:09 PM

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Ford re-engineered the distributor to make it as short as possible. They shortened the cam, had the distributor bushing extending back inside the motor and used the crab cap. everything possible to cut down the length. One innovation also introduced was to run the vacuum through a drilling in the timing cover.

A simple, elegant design.

Mart.

rustythumb · 12-04-2016, 12:41 AM

was not aware of that change. thanks, everyone!

Paul Bennett · 12-04-2016, 02:12 AM

Quote:

Originally Posted by V8COOPMAN

It's to supply a source for the vacuum brake on the distributor. DD

What is the 'vacuum brake' and it's function? Perchance a different name for 'advance'?

Ol' Ron · 12-04-2016, 09:56 AM

Every street engine needs two ignition advance curves, one for cruise and one for power. The vacuum brake provides that by allowing max advance st cruise and preventing detonation under hard acceleration.

flatjack9 · 12-04-2016, 11:24 AM

Quote:

Originally Posted by Paul Bennett

What is the 'vacuum brake' and it's function? Perchance a different name for 'advance'?

There is no vacuum brake on the distributor you show which is a 49 to 53 distributor. The vacuum brake was used on the earlier engines as a way to limit centrifugal under acceleration.

12-03-2016, 04:47 PM	#1
rustythumb Senior Member Join Date: Jun 2010 Location: orange co. ca. Posts: 178	flathead question just bought a '36 with later motor. i noticed it has a small copper tube going from a raised boss on the front cover to a boss on the intake manifold. my other flathead has nothing like that! anyone know what this is for? thanks!

12-03-2016, 04:57 PM	#2
V8COOPMAN Senior Member Join Date: May 2010 Location: East Shore of LAKE HOUSTON Posts: 11,115	Re: flathead question It's to supply a source for the vacuum brake on the distributor. DD __________________ *Click Links Below* __ ▼ *'35-'36 W/8BA & MECHANICAL FAN* *T5 W/TORQUE TUBE*

12-03-2016, 05:50 PM	#3
rustythumb Senior Member Join Date: Jun 2010 Location: orange co. ca. Posts: 178	Re: flathead question on my other motor, the tube goes to the distributor,not to the timing cover. why is this different ?

12-03-2016, 07:09 PM	#6
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,756	Re: flathead question Sponsored Links (Register now to hide all advertisements) Ford re-engineered the distributor to make it as short as possible. They shortened the cam, had the distributor bushing extending back inside the motor and used the crab cap. everything possible to cut down the length. One innovation also introduced was to run the vacuum through a drilling in the timing cover. A simple, elegant design. Mart.

12-04-2016, 12:41 AM	#7
rustythumb Senior Member Join Date: Jun 2010 Location: orange co. ca. Posts: 178	Re: flathead question was not aware of that change. thanks, everyone!

12-04-2016, 09:56 AM	#9
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,861	Re: flathead question Every street engine needs two ignition advance curves, one for cruise and one for power. The vacuum brake provides that by allowing max advance st cruise and preventing detonation under hard acceleration.