Counter balanced crank

So a Burlington crank should balance OK as it is a ford type design adapted to the A block?

If I add a really light flywheel I should be cooking with gas.

Does anyone do a much lighter flywheel than the ones cut down for the V8 clutch? Preferably something that can be sent in a pizza box. ;)

I think there is some info on the Ford garage about removing meat from the flywheel.
 
I have one simple question and this is in good faith, not trying to start anything.

How many of the people commenting on balancing have actually been to school on balancing, understand the physics of balancing and can run a balancer?
 
Kohnke,

I may not have understood all the prior posts, but my new Scat balanced Model A new crank seems fine along with lightened flywheel and V8 clutch pressure plate with a aligned bell housing etc.

Seems OK to me to go this route as not even a problem with judging guidelines for original.
 
Balancing the crank, pistons, con rods, flywheel and clutch will make a big difference in the performance and longevity of an A engine. I have a B and an A with welded on counterweights and both of them have been balanced and they’re both strong runners. Don’t know what the current prices for balancing an engine are, but it is a worthwhile investment
 
kimeccles said:
Kohnke,

I may not have understood all the prior posts, but my new Scat balanced Model A new crank seems fine along with lightened flywheel and V8 clutch pressure plate with a aligned bell housing etc.

Seems OK to me to go this route as not even a problem with judging guidelines for original.
Click to expand...

I agree, and have put many in bearings.

Herm.
 
I wrote a paper on Re-Engineering the Model A Engine in 2007.

Do a Google search on "Re-Engineering the Model A Engine", and you should find it.

In the paper, the discussion on crankshaft design has an equation that engineers use to determine how much counterweight is needed for any engine.

The following is from that paper, however it is missing the figure (Figure 4)




Counterweight calculation is an engineering determination of how large the counterweights should be. Counterweight calculation is different than balancing. Balancing is making things equal. A stock Model A crankshaft (without counterweights) is balanced when it’s center of gravity lies along the centerline axis. Small amounts of weight are added or removed to get the center of gravity on axis. Balancing can be either static (pistons, wrist pins, and connecting rods) or dynamic in the case of things that rotate (crankshaft, flywheel, etc).


Stock Model A and 1st generation Model B crankshafts have no counterweights. The 2nd generation Model B crankshaft had integral counterweights equivalent to about 40% of modern engine standards, and the late ‘30’s factory rebuilt Model B engines had pressed on counterweights equivalent to about 60% of modern engine standards. In both cases, the counterweights are placed on one side of the connecting rod instead of being equal on both sides of the connecting rod as on a modern engine. Placing the counterweight on one side introduces cyclic bending loads into the crankshaft (deflection and fatigue) with every revolution. These cyclic loads increase as the square of the RPM. Each doubling of RPM causes loads (stresses) and deflections to increase four times.


The new crankshaft resulting from this engineering study has a pair of identical counterweights for each cylinder that are spaced equally fore and aft from the connecting rod as on a modern engine. These counterweights take care of what engineers call "first order effects" as they reduce crankshaft stress and deflection.

Picture
Figure 4, Counterweights and Crank Arm

Figure 4 is an exploded view that illustrates the pair of identical counterweights on the left and the crank arm on the right that is used for each cylinder.




The equation used to determine the amount of weight for the pair of counterweights is shown below.

CW x A = (CA x B) + (BE + .5 x SE) x C where:

CW is the weight of the pair of counterweights

A is the distance from centerline axis of crankshaft to cg of counterweights

CA is the weight of the crank arm

B is the distance from centerline axis of crankshaft to cg of crank arm

BE is the big end weight of the connecting rod

.5 is a constant (good up to ~ 7000 RPM, increases to .55 @ 18,000RPM)

SE is the small end weight of the connecting rod including weight of piston, wrist pin, and rings

C is the distance from centerline axis of crankshaft to centerline of connecting rod journal (2.125 inches), (1/2 of 4.25 in. stroke)


There was just enough room in the crankcase for the 100% counterweights if they are made from the same material as the crankshaft (ductile iron). The counterweights could become less if the crank arm, connecting rod, or piston were lighter. The counterweights could also become smaller and have the same effect if they were made of a denser material such as tungsten.
 
Pete said:
I have one simple question and this is in good faith, not trying to start anything.

How many of the people commenting on balancing have actually been to school on balancing, understand the physics of balancing and can run a balancer?
Click to expand...

Pete, I have done none of it, but I have a friend that had done many years of balancing, and he done them right, as I have watched him for hours on end, and when he drilled holes to remove weight, they all looked like the factory put them there.

The bad thing now is, balance machines, at least, in Iowa, are far and few between. And the real bad part is a large percent of those, don't know all they are supposed to. To get anything done at this time, I have to drive 70 miles.

Herm.
 
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