The Ford Barn

41Joe · 09-28-2016, 09:46 AM

I just removed the flywheel from my engine. It uses the 9" clutch. This flywheel has a big lip that surrounds the clutch. I don't have any pictures of it.
The attached picture I got off the web. It's the only one I could find.
Is there any particular reason for this design? Is it just to add weight? Does it keep the pressure plate concentric to the flywheel?

JSeery · 09-28-2016, 09:58 AM

The added weight helps smooth out the engine and adds inertia. It's usefulness depends on the intended use and type of vehicle it is in. For a heavy truck hauling a load it is a plus, for a light weight high performance application it is a negative. The greater the inertia the slower the acceleration. The lip is often machined off for an application where you are interested in increased acceleration and performance. Like almost everything else, it's a balancing act.

Bluebell · 09-28-2016, 02:34 PM

Following on from JSeery, The flywheel is, as it was, Henry Ford's design of choice, having factored in his chosen specs of everything else;
The fuel available,
The weight of the car / truck and the load,
Cam specs, bore stroke,compression ratio, gearbox ratios, final drive ratio, tyres, durabilty of design, driver comfort, etc etc etc. (we can add stuff, ad nauseum)
The idea of the lip outside of the clutch assembly is that the maximum effect of the mass is at the greatest diameter possible (given practical limits) (if it was closer to the middle, more weight would be needed)
From the standard production overall performance view point, what you have was the best all round result. (or Henry woulda done it different)

Fred A · 09-28-2016, 11:03 PM

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That's a big assed flywheel for a postwar engine. Shame by that time not enough of the donut flywheels had gone to scrap during the war along with the 9" clutches. 10" was the new 9". Probably because of the bloat that started with the '42. May be forced to go heavy if the long gears in my '40 causes sluggish starts. Many factors come into play finding that ideal. Good Luck: Fred A

09-28-2016, 09:58 AM	#2
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: Flywheels The added weight helps smooth out the engine and adds inertia. It's usefulness depends on the intended use and type of vehicle it is in. For a heavy truck hauling a load it is a plus, for a light weight high performance application it is a negative. The greater the inertia the slower the acceleration. The lip is often machined off for an application where you are interested in increased acceleration and performance. Like almost everything else, it's a balancing act.

09-28-2016, 02:34 PM	#3
Bluebell Senior Member Join Date: Nov 2012 Location: Tauranga, New Zealand Posts: 726	Re: Flywheels Following on from JSeery, The flywheel is, as it was, Henry Ford's design of choice, having factored in his chosen specs of everything else; The fuel available, The weight of the car / truck and the load, Cam specs, bore stroke,compression ratio, gearbox ratios, final drive ratio, tyres, durabilty of design, driver comfort, etc etc etc. (we can add stuff, ad nauseum) The idea of the lip outside of the clutch assembly is that the maximum effect of the mass is at the greatest diameter possible (given practical limits) (if it was closer to the middle, more weight would be needed) From the standard production overall performance view point, what you have was the best all round result. (or Henry woulda done it different) Last edited by Bluebell; 09-28-2016 at 02:41 PM.

09-28-2016, 11:03 PM	#4
Fred A Senior Member Join Date: May 2010 Location: Encino California, near Burbank Posts: 935	Re: Flywheels Sponsored Links (Register now to hide all advertisements) That's a big assed flywheel for a postwar engine. Shame by that time not enough of the donut flywheels had gone to scrap during the war along with the 9" clutches. 10" was the new 9". Probably because of the bloat that started with the '42. May be forced to go heavy if the long gears in my '40 causes sluggish starts. Many factors come into play finding that ideal. Good Luck: Fred A