The Ford Barn

jtucker · 10-16-2023, 05:06 PM

Does anyone know where I can buy a lightened flywheel for my '31 coupe?

Bob C · 10-16-2023, 05:25 PM

https://burtzblock.com/products/flywheels

Smokedtires · 10-16-2023, 06:12 PM

How does a lightened flywheel affect MPG? I understand the ability to spin rpms quicker, but I would think the heavier flywheel would carry rpms longer saving gas on a touring engine. As I prepare to have new bearings installed in my engine, this is also a consideration.

Easy · 10-16-2023, 06:40 PM

Is your crankshaft counter balanced? If not I don’t know if you would want to take weight off the flywheel.

JayJay · 10-16-2023, 06:41 PM

You might want to look at this discussion from a few years ago. Raises some very good questions.

updraught · 10-16-2023, 08:08 PM

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Quote:

Originally Posted by Smokedtires

How does a lightened flywheel affect MPG? I understand the ability to spin rpms quicker, but I would think the heavier flywheel would carry rpms longer saving gas on a touring engine. As I prepare to have new bearings installed in my engine, this is also a consideration.

The flywheel stores and releases energy. When you take off with a light flywheel you will save on gas, but need more going up the next hill as you haven't stored much energy when taking off. In stop start conditions with a heavy flywheel you will probably waste the stored energy each time you stop.

Pete · 10-16-2023, 08:34 PM

Quote:

Originally Posted by jtucker

Does anyone know where I can buy a lightened flywheel for my '31 coupe?

Most any general machine shop can lighten one for you.
If you do that, you should have the flywheel/clutch and disc balanced, each separately and then the flywheel and clutch cover as an assembly.

emf · 10-17-2023, 06:30 AM

Be aware, Burtz's lightened flywheel is drilled for the v8 clutch.

Frank

BRENT in 10-uh-C · 10-17-2023, 06:41 AM

Quote:

Originally Posted by jtucker

Does anyone know where I can buy a lightened flywheel for my '31 coupe?

Dave is in Minnesota and looks like he is pretty close to you. He has experience with what you are looking for. Maybe give him a call?

http://www.durableperformance.net/about.html

nkaminar · 10-17-2023, 10:10 AM

Flywheel weight (rotational inertia) is more complicated than initially perceived. The crankshaft has rotational vibration at all speeds, more at some speeds called critical rpm. The Ford engineers were either pretty lucky or pretty smart in that the flywheel inertia was just enough to cancel out the rotational vibration of the crankshaft so that it was not felt by the driver.

There is a spot along the length of the crankshaft where there is no rotational vibration, called a node point. With the original flywheel that point is the flywheel. With a lightened flywheel the node point moves forward so that now the flywheel is experiencing rotational vibration. The driver can feel this in the steering wheel when driving a car with a lightened flywheel. More so at lower rpm.

The addition of counterbalancing weights complicates this and changes where the node point is and how much rotation vibration is felt in the lightened flywheel.

The rotational vibration causes stress in the crankshaft and will lead to breakage under certain conditions. The addition of a vibration (rotational) dampener at the front of the crankshaft will reduce the rotational stress in the crankshaft.

Pete · 10-17-2023, 03:28 PM

Quote:

Originally Posted by nkaminar

Flywheel weight (rotational inertia) is more complicated than initially perceived. The crankshaft has rotational vibration at all speeds, more at some speeds called critical rpm. The Ford engineers were either pretty lucky or pretty smart in that the flywheel inertia was just enough to cancel out the rotational vibration of the crankshaft so that it was not felt by the driver.

There is a spot along the length of the crankshaft where there is no rotational vibration, called a node point. With the original flywheel that point is the flywheel. With a lightened flywheel the node point moves forward so that now the flywheel is experiencing rotational vibration. The driver can feel this in the steering wheel when driving a car with a lightened flywheel. More so at lower rpm.

The addition of counterbalancing weights complicates this and changes where the node point is and how much rotation vibration is felt in the lightened flywheel.

The rotational vibration causes stress in the crankshaft and will lead to breakage under certain conditions. The addition of a vibration (rotational) dampener at the front of the crankshaft will reduce the rotational stress in the crankshaft.

Flathead B circle track engine with 12 lb. big block Chev damper. NO flywheel or clutch. (in/out rear end) Less felt vibration than a stock A/B engine.
6500 rpm twice a lap. 168 hp at 5800 rpm.

Flathead · 10-17-2023, 03:59 PM

I can't really tell from the picture, is that flat or overhead?

Pete · 10-17-2023, 04:03 PM

Quote:

Originally Posted by Flathead

I can't really tell from the picture, is that flat or overhead?

Dan Price flathead, modified to 14 to 1.

nkaminar · 10-17-2023, 05:50 PM

Pete, how is the vibration at 1,200 rpm? Your vibration dampener is doing its job.

Pete · 10-17-2023, 06:02 PM

Quote:

Originally Posted by nkaminar

Pete, how is the vibration at 1,200 rpm? Your vibration dampener is doing its job.

I never checked it. It idled at about 2000.
That engine is in some museum now and I don't know what one.

ModelA29 · 10-17-2023, 07:39 PM

I picked up a trick B engine a couple weeks ago. Aluminum flywheel and homemade dampner (not sure if that's right since there is no rubber in it). It's got a cross drilled "C" (yeah I know - no such thing) crank.
I'm always reminded of lessons from a friend while building race cars. Make it light - every pound you take out is a pound you don't have to accelerate or stop.

nkaminar · 10-18-2023, 08:14 AM

29, That is an interesting engine. The "dampener" looks like a flywheel more than a dampener. Putting flywheels at each end of the crankshaft will change things and I am not sure how things will change. Usually the most extreme twisting is at the front.

Dampeners have two ways of dampening the torsional vibration. One is through the rubber connection to a heavy disk and the other is through some sort of friction connection. The rubber connection actually wears out after a while because of the constant flexing. Dampeners are designed for each engine using computer simulation and testing. It is not something that an average gear head can do.

BRENT in 10-uh-C · 10-18-2023, 08:45 AM

Quote:

Originally Posted by nkaminar

29, That is an interesting engine. The "dampener" looks like a flywheel more than a dampener. Putting flywheels at each end of the crankshaft will change things and I am not sure how things will change. Usually the most extreme twisting is at the front.

Dampeners are designed for each engine using computer simulation and testing. It is not something that an average gear head can do.

Y'all really want to discuss the effectiveness of a balancer on a Model-A/B engine, explain how this one works??

JayJay · 10-18-2023, 10:13 AM

Quote:

Originally Posted by BRENT in 10-uh-C

Y'all really want to discuss the effectiveness of a balancer on a Model-A/B engine, explain how this one works??

Looks like something you might see on a hit-and-miss engine...

johnneilson · 10-18-2023, 11:50 AM

It doesn’t

J

10-16-2023, 05:06 PM	#1
jtucker Member Join Date: Nov 2014 Location: Roseville, MN Posts: 32	Lightened flywheel Does anyone know where I can buy a lightened flywheel for my '31 coupe?

10-16-2023, 05:25 PM	#2
Bob C Senior Member Join Date: May 2010 Location: So Cal Posts: 8,756	Re: Lightened flywheel https://burtzblock.com/products/flywheels

10-16-2023, 06:12 PM	#3
Smokedtires Senior Member Join Date: Jun 2022 Location: Baldwinsville NY Posts: 174	Re: Lightened flywheel How does a lightened flywheel affect MPG? I understand the ability to spin rpms quicker, but I would think the heavier flywheel would carry rpms longer saving gas on a touring engine. As I prepare to have new bearings installed in my engine, this is also a consideration.

10-16-2023, 06:40 PM	#4
Easy Junior Member Join Date: Mar 2014 Posts: 12	Re: Lightened flywheel Is your crankshaft counter balanced? If not I don’t know if you would want to take weight off the flywheel.

10-16-2023, 06:41 PM	#5
JayJay Senior Member Join Date: Jan 2020 Location: SF Bay Area Posts: 1,080	Re: Lightened flywheel You might want to look at this discussion from a few years ago. Raises some very good questions. __________________ JayJay San Francisco Bay Area ------------------------ 1930 Murray Town Sedan 1931 Briggs S/W Town Sedan

10-17-2023, 06:30 AM	#8
emf Senior Member Join Date: Mar 2013 Location: Hudson, NY Posts: 511	Re: Lightened flywheel Be aware, Burtz's lightened flywheel is drilled for the v8 clutch. Frank

10-17-2023, 10:10 AM	#10
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,904	Re: Lightened flywheel Flywheel weight (rotational inertia) is more complicated than initially perceived. The crankshaft has rotational vibration at all speeds, more at some speeds called critical rpm. The Ford engineers were either pretty lucky or pretty smart in that the flywheel inertia was just enough to cancel out the rotational vibration of the crankshaft so that it was not felt by the driver. There is a spot along the length of the crankshaft where there is no rotational vibration, called a node point. With the original flywheel that point is the flywheel. With a lightened flywheel the node point moves forward so that now the flywheel is experiencing rotational vibration. The driver can feel this in the steering wheel when driving a car with a lightened flywheel. More so at lower rpm. The addition of counterbalancing weights complicates this and changes where the node point is and how much rotation vibration is felt in the lightened flywheel. The rotational vibration causes stress in the crankshaft and will lead to breakage under certain conditions. The addition of a vibration (rotational) dampener at the front of the crankshaft will reduce the rotational stress in the crankshaft. __________________ 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.

10-17-2023, 03:59 PM	#12
Flathead Senior Member Join Date: May 2010 Location: Southern Maine Posts: 1,499	Re: Lightened flywheel I can't really tell from the picture, is that flat or overhead?

10-17-2023, 05:50 PM	#14
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,904	Re: Lightened flywheel Pete, how is the vibration at 1,200 rpm? Your vibration dampener is doing its job. __________________ 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.

10-18-2023, 08:14 AM	#17
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,904	Re: Lightened flywheel 29, That is an interesting engine. The "dampener" looks like a flywheel more than a dampener. Putting flywheels at each end of the crankshaft will change things and I am not sure how things will change. Usually the most extreme twisting is at the front. Dampeners have two ways of dampening the torsional vibration. One is through the rubber connection to a heavy disk and the other is through some sort of friction connection. The rubber connection actually wears out after a while because of the constant flexing. Dampeners are designed for each engine using computer simulation and testing. It is not something that an average gear head can do. __________________ 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.

10-18-2023, 11:50 AM	#20
johnneilson Senior Member Join Date: Jun 2010 Location: 34.22 N 118.36 W Posts: 1,057	Re: Lightened flywheel It doesn’t J __________________ As Carroll Smith wrote; All Failures are Human in Origin.