Lightened Flywheel

[Bob Bidonde]

The flywheel dampens the torsional impulses in the crankshaft from the power stroke, the compression stroke, acceleration and deceleration of the crankshaft's RPM (changes in momentum: Force x length of time applied = mass x velocity). Putting a small damper on the front of the crankshaft is money wasted because it has a minuscule mass and radius of gyration relative to the flywheel.
The flywheel is also a gyro, so it opposes changes in its rotational axis and dampens the engine's tendency to rock vertically about the rear engine mounts.
Lightening the flywheel gives the engine a mechanical advantage to accelerate / decelerate quicker (change engine's momentum). So lightening the flywheel a significant amount (pounds, not ounces) improves acceleration, shifting, braking, reduces rear main bearing stress and should improve gas mileage. On the other hand, lightening the flywheel decreases its ability to dampen the engine's impulses and vibrations. Thus it is a trade-off to lighten a flywheel.
The trade-off is worthwhile in my opinion, so I favor lightening the flywheel for improvement of the car's performance. By the way, the weight of a stock flywheel and clutch is 80 lbs.

 

[Licensed to kill]

The flywheel dampens the torsional impulses in the crankshaft from the power stroke, the compression stroke, acceleration and deceleration of the crankshaft's RPM (changes in momentum: Force x length of time applied = mass x velocity). Putting a small damper on the front of the crankshaft is money wasted because it has a minuscule mass and radius of gyration relative to the flywheel.

OK, so how about putting a damper on the front AFTER removing much of that excess mass from the flywheel??

The flywheel is also a gyro, so it opposes changes in its rotational axis and dampens the engine's tendency to rock vertically about the rear engine mounts.
Lightening the flywheel gives the engine a mechanical advantage to accelerate / decelerate quicker (change engine's momentum). So lightening the flywheel a significant amount (pounds, not ounces) improves acceleration, shifting, braking, reduces rear main bearing stress and should improve gas mileage. On the other hand, lightening the flywheel decreases its ability to dampen the engine's impulses and vibrations. Thus it is a trade-off to lighten a flywheel.
The trade-off is worthwhile in my opinion, so I favor lightening the flywheel for improvement of the car's performance. By the way, the weight of a stock flywheel and clutch is 80 lbs.

On the "plus" side of the heavy flywheel is that it seems near impossible to stall taking off. All that mass rotating helps the engine to get these little cars going from a dead stop. This is one of the reasons i plan to teach my grandkids to drive on the A. Easier to learn to take off, nat as easy as a synchro trans but not too difficult to shift, if they can drive this they can drive anything and how many kids these days can say they learned to drive on a Model A.

 

[Jack Shaft]

Every modern engine uses a useless harmonic balancer.A flywheel stores kinetic energy and dampens impulse. On one end of the crankshaft....what about the other? Henry Fords heavy flywheel cure for torsional vibration was seen by his engineers as ineffective by years ago,it remains today..

 

[Jack Shaft]

the next time you change a cracked or broken front pulley ask yourself " why did this happen?"..think about the effect that cracked the cast pulley has on main bearings..dont just run out and buy a two piece pulley to make the "next time" easier...fix the root cause

 

[Pete]

12 lb.

 

[Jack Shaft]

Buddy of mine has a Kong Jackson aluminum lightweight flywheel,it looks like a salad plate.

 

[Pete]

Buddy of mine has a Kong Jackson aluminum lightweight flywheel,it looks like a salad plate.

I use SBC 12 lb. flywheels. Re-drill is easy. They are 100 bucks on eBay.
The closer you can get the weights on each end of the crank, the
less TORSIONAL vibration and the longer the crank lasts.

 

[Y-Blockhead]

Every modern engine uses a useless harmonic balancer.A flywheel stores kinetic energy and dampens impulse. On one end of the crankshaft....what about the other? Henry Fords heavy flywheel cure for torsional vibration was seen by his engineers as ineffective by years ago,it remains today..

FWIW, I use a Murray Horn harmonic balancer on my Town Sedan.

 

[Licensed to kill]

FWIW, I use a Murray Horn harmonic balancer on my Town Sedan.

What is your experience with it??.

 

[Jim Brierley]

Every modern engine uses a useless harmonic balancer.A flywheel stores kinetic energy and dampens impulse. On one end of the crankshaft....what about the other? Henry Fords heavy flywheel cure for torsional vibration was seen by his engineers as ineffective by years ago,it remains today.

If they are ineffective, why to the penny-pinching manufactures put them there? Think about it!

 

[Y-Blockhead]

Every modern engine uses a useless harmonic balancer. A flywheel stores kinetic energy and dampens impulse. On one end of the crankshaft....what about the other? Henry Fords heavy flywheel cure for torsional vibration was seen by his engineers as ineffective by years ago,it remains today..

Not sure I understand why you make this comment? In another thread you state you installed a Murray Balancer?? Or were you being facetious and it went over my head?

Your comment; "Put one of murrays on my car.. can feed a B width belt sideways to install. Bronze cam gear chatter minimized.Logic says reducing harmonic vibration should help extend main bearing life with a dynamically balanced crankshaft..time will tell."

https://www.fordbarn.com/forum/showthread.php?t=278736&highlight=Harmonic+balancer

What is your experience with it??.

See this thread: https://www.fordbarn.com/forum/showthread.php?t=278736&highlight=Harmonic+balancer