"New Engine" Balancing"

[Terry Burtz, Calif]

The "New Engine" is manufactured in factories that produce engines for current Japanese, European, and Domestic automobile and truck production.

The "New Engine" parts are balanced to the same tolerances as other parts made in these factories and the balance is adequate for most applications.

We are aware that balance can be better for unique applications beyond normal driving within speed limits on paved roads.

We have a problem with "Builders" that claim the "New Engine" parts are not balanced and use balancing as a line item on a build sheet to increase their profit. One "Builder" sent the following correspondence to a potential buyer "The engine is not balanced unless you had it balanced. This is a common misconception as the flywheel crankshaft, pressure plate and rods and pistons all have to be balanced together for best results."

The crankshaft, connecting rods, and flywheel of the "New Engine" are balanced separately to the same tolerances as a modern engine. Any set of connecting rods combined with any crankshaft combined with any flywheel will be in balance to modern engine tolerances. Balancing everything as one assembly and match marking parts is a bad idea because if 1 part is changed, the entire assembly must be rebalanced.

"Buyers" need to be aware of false claims made by "Builders" and report false claims to me at [email protected]. Please do not subject yourself to criticism by reporting anything on public forums.

The cost to assemble an engine is increasing due to inflation and we get upset when a "Builder" claims the increased costs are because the "New Engine" parts are not balanced.

[Kurt in NJ]

What are the “ modern engine “tolerances for balance and how do they compare to the original Ford balancing tolerance ?
If you don’t publish the actual specifications how can the builder be able to know if it is out of specifications?

[johnneilson]

Kurt

The subject of “balancing” the engine is another misunderstood science
I would suggest doing a little research on the ISO balancing standards

Once you determine the actual operating speed and rotating mass you will understand the original Ford specifications might have been a little optimistic

As a once well known balancing guru said “any balancing done beyond ISO specs is just pure entertainment”

John

[Terry Burtz, Calif]

Thanks, John Neilson,
There is a normal car (Grocery Getter) balance, Circle track balance, Formula 1 balance, turbine balance, and Gyroscope balance for rotors that spin at 48,000 RPM.
Any of these are suitable for a Model A Ford.

[Jim Brierley]

Balancing a 4 cyl. engine does not have to be done as a unit, the crank, rods, flywheel, etc. can al be done separately.

[nkaminar]

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No inline engine will be perfectly balanced. Consider this: When the pistons are at top dead center or at bottom dead center they are reversing direction. The mass of the pistons, rings, piston pins, and the mass of the little end of the rod all have to be accelerated and the force involved is counteracted by the counter weights. However, when the engine has turned approximately 90 degrees, the pistons, rings, etc. are not being accelerated and the counter weights only have to react against the big end of the rods and crank pins. So no one counter weight can do both these jobs. Counter weights that if big enough at top dead center and bottom dead center will be too big at the 90 degree point, and counter weights that are the right size for the 90 degree point will be too small at top dead center or bottom dead center.

The counter weights are a compromise between the two.

The Burtz design has two counter weights for each piston, 8 in total. Previous designs of counter weighted cranks for the A and B engines had only counter weights at 4 locations. Stock A cranks had none. The engine in my completely stock 1930 Model A that I drove in high school would vibrate like crazy at 55 mph. My Burtz engine does not feel like it is coming apart at this speed or higher like my stock A did.

[johnneilson]

To add one more point
The inline 4 cylinder engine suffers from the fact that the offset piston acceleration between top and bottom of stroke causes harmonics that cannot be dampened without adding a counter shaft that is selectively unbalanced

Reducing piston/pin and small end rod weights helps with the harmonics

John

[Dan McEachern]

"As a once well known balancing guru said “any balancing done beyond ISO specs is just pure entertainment” ".

yea, but its still fun to see how close you can get things past the spec! When you start chasing the unbalance, that's when you know to stop and move on.

[Synchro909]

I thought being "unbalanced" was a requirement for taking part in this hobby.

[Bob-A]

Originally Posted by Synchro909

I thought being "unbalanced" was a requirement for taking part in this hobby.

I totally agree!


Bob-A


"Skirts are for Women not Car Fenders"

[David in San Antonio]

I tell people that every person in the Model A hobby is eccentric, except me. They always laugh.

[40 Deluxe]

Originally Posted by Terry Burtz, Calif

The "New Engine" is manufactured in factories that produce engines for current Japanese, European, and Domestic automobile and truck production.

The "New Engine" parts are balanced to the same tolerances as other parts made in these factories and the balance is adequate for most applications.

We are aware that balance can be better for unique applications beyond normal driving within speed limits on paved roads.

We have a problem with "Builders" that claim the "New Engine" parts are not balanced and use balancing as a line item on a build sheet to increase their profit. One "Builder" sent the following correspondence to a potential buyer "The engine is not balanced unless you had it balanced. This is a common misconception as the flywheel crankshaft, pressure plate and rods and pistons all have to be balanced together for best results."

The crankshaft, connecting rods, and flywheel of the "New Engine" are balanced separately to the same tolerances as a modern engine. Any set of connecting rods combined with any crankshaft combined with any flywheel will be in balance to modern engine tolerances. Balancing everything as one assembly and match marking parts is a bad idea because if 1 part is changed, the entire assembly must be rebalanced.

"Buyers" need to be aware of false claims made by "Builders" and report false claims to me at [email protected]. Please do not subject yourself to criticism by reporting anything on public forums.

The cost to assemble an engine is increasing due to inflation and we get upset when a "Builder" claims the increased costs are because the "New Engine" parts are not balanced.

Thank you, Terry, for clearing this up. The automotive hobby is overloaded with wrong, misleading, and outright false information, including the subject of balancing! I don't know which is worse, ignorant ideas being spread by the clueless, or outright falsehoods being promoted by the dishonest!

[Bruce of MN]

Originally Posted by David in San Antonio

I tell people that every person in the Model A hobby is eccentric, except me. They always laugh.

I knew there was at least one other normal guy in the hobby!