Vibration removal tips and tricks. Have any?

Depends on how much work you want to do,,,,,when you find the spot that helps, take the weight off of that and put weight on the bolts on either side of that, or the next two or even the next two, it seems that two spots for added mass gives a bit more control.
Two weights across from each other are counteracting each other in relation to the radius of just one weight, so the closer they are moved toward each other the heavier the weight becomes, also,, sometimes a bit of weight moved around on the heavy side combined with the weight in a couple of places on the light side can dial it in a bit better.
It's about like cheating while playing the lottery, you will win but it might take a while.
Once you go through the whole routine and get a feel for what is happening you will have to settle upon at what rpm you want the remainder of the vibration to end up at.(I am assuming that it won't completely disappear, as are 300 others!) :)
I hope the clutch disc is centered with a good pilot and it is balanced, as you can see it doesn’t take much to make a big difference.
It is a challenge and I do like a challenge, someone once told me it couldn’t be done,,,,their mistake.
 
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Nice video Art.


With the engine all exposed like that after I mastered the flywheel, I'd probably put two opposing straps on the front pulley bolt just to see what could be done,, they have to start out even and balanced then slightly move toward each other to add a touch of weight.

Why would I do that,,,, I'm nuts, just plain ol bloody nuts I tell ya, inquiring minds need to know!
 
I've flown radio control model planes since the 70s, and have balanced a lot of props and spinners. It seems to be a bit of voodoo really. A perfectly balanced prop and spinner may still vibrate because the engine its self doesn't have enough counterbalancing. Most of the time and out of balance prop/spinner combination may work better if you can find the magic spot that is clocked to offset the engine.
This engine is something I picked up and inspected/dis-assembled over the winter to fill the void while I looked over it's original engine that ran good, but was under-powered. I guess my question would be "will a balanced flywheel/pressure-plate help the situation if the engine its self is out of balance?". I'm wondering also if when back in the car, the added mass it's bolted to wouldn't absorb some of that energy vs my 25 pound engine stand?
 
What I was trying to illustrate with the video, is where the most part of the vibration happens in the rpm range. My coil is only mounted with one bolt and that's what you hear clunking. As I take the rpms up I try to hold it at the point it rattles. Any variation of the throttle at that point now stops the rattle, so the band of rpm range to make it rattle is very tight now... wasn't the case before. Also, now as I raise the rpms up to a cruising range, the vibs are staying pretty much constant instead of continually increasing with rpm.
 
Art, I agree with your #46 post.
With #45, I say no. Every part inside the engine needs to be well balanced, and a counterweighted crankshaft needs to be added to get the vibrations to a minimum.
 
katy said:
Nor sure what you mean by clocking, methinks you mean balancing?
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Clocking simply means (in this case) with the flywheel in a fixed position, taking the pressure-plate loose and rotating/indexing it to the next bolt then running the engine to see if it has helped any. Theory being that the pressure-plate isn't perfectly balanced and my offset some unbalance in the engine/flywheel. And yes... it is tedious.:)
 
Tom Wesenberg said:
Art, I agree with your #46 post.
With #45, I say no. Every part inside the engine needs to be well balanced, and a counterweighted crankshaft needs to be added to get the vibrations to a minimum.
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That's my thoughts as well. I can find no local machine shop that will to do a balance for me, would need to be shipped out... I hate shipping big heavy stuff! It is such a big improvement that I will undoubtedly reinstall everything and give it a try. May not be perfect but hopefully enough improved that I can put up with it. On another note, while taking things apart, I noticed an accumulation of soot around the tail-pipe/muffler connection on my 9 month old Aries muffler... a closer inspection reveals a poor weld. sheese...:rolleyes:
 
Maybe one/some of you, if you fire up your A in the next few days, you could slowly advance your throttle and take note to if/when you have the most vibration? The main problem is really not knowing what average/acceptable is.
 
30 Tudor said:
If you figure the radius of 5.2 inches for the placement of the flywheel bolts,
at this radius,,,,
@ 1000 rpm
1 gram weighs .32 lb
6.6 grams weighs 2.14 lb (6.6 grams = 3/8 nut)
20 grams = 8.59 lbs

@ 2000 rpm
1 gram = 1.3 lbs
6.6 grams = 8.59
20 grams = 26 lbs

And the tiny little itty bitty insignificant 1/4" lock washer weighs in at 1.8 grams
1.8 grams @ 1000 rpm = .58 lbs
1.8 grams @ 2000 rpm = 2.34 lbs

The engine is probably not this far off balance,
probably should try small amounts of weight.

This isn't a theory, it can and has been done, it doesn't always take much.

The best way is when the engine is being built,, however the piston and rod assembly's were 20 grams apart when I got them back from the re builder so it doesn't always work out. I tossed them and started over!
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please don't misunderstand, I agree with you. But I do have one question about the equations above are they taking in the dampening effect of a 63 pound flywheel?
 
Railcarmover said:
please don't misunderstand, I agree with you. But I do have one question about the equations above are they taking in the dampening effect of a 63 pound flywheel?
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The flywheel is not for rotational balance but for damping of the torque of the power thrusts. If it is removed the thrust would rattle the trans and rear end gears. A good example of this is on motorcycles, I've owned a bunch, and they all had a spot or two where the transmissions rattle like crazy where the engine thrusts coincide with the gearing, the flywheels are not heavy enough to prevent this, and the design of the crank to the gear box almost begs for it. I have a BMW right now and it is no exception, I know what it is but it still bugs me, it could be engineered out, but it's not cost effective.When you hear a big truck go a bit too slow and the rattling of the drive line and the trans chatter is caused by the power thrusts of the engine,,an engine spins erratically. On modern engines the computer can read a dead cylinder by the amount time the rpm slows down between cylinders firing. Now that sounds crazy to me, but true.

Henry was all about being cost effective, the model a crank is a tough piece of spaghetti, it twists and turns and springs between all the thrusts of the rods, that big weight is to transfer that erratic heartbeat into one smooth power source. It will not keep an engine from shaking, if the rotational forces are out of balance. It might mask them a little bit,,but
 
Art Newland said:
Interesting read on FAMs and Model A engine vibrations and why.
https://www.fordbarn.com/forum/showpost.php?p=1471537&postcount=2
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That is a good article,,,

The dynamic rotational balance can be greatly improved on an external application, turbines are balanced this way.

The rest of it you're stuck with.

Right now I have two rebuilt rods the difference of which is 100 grams between the two lightest and the two heaviest, on the large end alone.
If these were placed as pairs on the same side of the crank, @ 2000 rpm it comes to 52 pounds,, that is at 2.1 inches from center-line.

You can never begin to guess what is inside an engine, or why it shakes, unless you check it all out,,all things are possible, and the only way to find out truthfully,the normal vibration patterns is to ask someone like Herm, or other reputable rebuilders what a balanced A engine should feel like.
Or someone specifically running those engines

I won;t put anything together unless it is perfect, or close to.
 
30 Tudor said:
The flywheel is not for rotational balance but for damping of the torque of the power thrusts. If it is removed the thrust would rattle the trans and rear end gears. A good example of this is on motorcycles, I've owned a bunch, and they all had a spot or two where the transmissions rattle like crazy where the engine thrusts coincide with the gearing, the flywheels are not heavy enough to prevent this, and the design of the crank to the gear box almost begs for it. I have a BMW right now and it is no exception, I know what it is but it still bugs me, it could be engineered out, but it's not cost effective.When you hear a big truck go a bit too slow and the rattling of the drive line and the trans chatter is caused by the power thrusts of the engine,,an engine spins erratically. On modern engines the computer can read a dead cylinder by the amount time the rpm slows down between cylinders firing. Now that sounds crazy to me, but true.

Henry was all about being cost effective, the model a crank is a tough piece of spaghetti, it twists and turns and springs between all the thrusts of the rods, that big weight is to transfer that erratic heartbeat into one smooth power source. It will not keep an engine from shaking, if the rotational forces are out of balance. It might mask them a little bit,,but
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As you are saying,rotational balance is a factor along with dampening.I balance piston and rod assemblies to .05g on other engines,the effect of balancing on overall performance is astounding,not only does it lessen vibration they shift easier and there is less overall wear on the entire drivetrain.My question is on your offset weight effect..not arguing that offset weight can be assigned a value,my question is does the flywheel dampen the effect of the added weight.In your example about the rods,your calculations come to 52 pounds..does the dampening effect of the flywheel 'absorb' some of the offset?is their a factor of flywheel weight in determining overall effect on balance?
 
Railcarmover said:
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As you are saying,rotational balance is a factor along with dampening.I balance piston and rod assemblies to .05g on other engines,the effect of balancing on overall performance is astounding,not only does it lessen vibration they shift easier and there is less overall wear on the entire drivetrain.My question is on your offset weight effect..not arguing that offset weight can be assigned a value,my question is does the flywheel dampen the effect of the added weight.In your example about the rods,your calculations come to 52 pounds..does the dampening effect of the flywheel 'absorb' some of the offset?is their a factor of flywheel weight in determining overall effect on balance?
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I am not qualified to answer your questions in any scholastically educated way, only from the stance of actually doing it, of knowing how to go about getting it done to an acceptable functional level.

It would stand to reason that there would be a greater change to the center of a rotational mass if 52 lbs were added to a 10 lb flywheel vs. a 65 lb flywheel.

You are calling the extra weight on the flywheel an offset of weight,,,
it appears to be a confusing way to think about.
Because there is rotational vibration,,, then there is already an offset of weight so to speak to the central line of rotation. The bearings force the rotating mass into one plane or rotation and hold it there while the mass itself wants to rotate on another center line. It is the rotating piece trying to straighten itself in to a balanced center of rotation that is felt.
All of the weight out of line with the forced center of rotation then becomes like a rock spun around by a rope, the faster you spin it the further it will fly when you let go as the g forces increase.
When weight is added to the rotating mass to counter act the force of the rock pulling on the center line, it is now being held to the center line by the opposing weight,,called the counterweight. Theoretically it is now held into a balanced orbit and will go nowhere but around the center of rotation.
The idea of adding weight to the flywheel to alter the center line of rotation works to put the rotating mass back on the correct center line, even if the out of balance is a rod, or even a missing rod. The added weight is not then an offset of weight out there slinging around, it is pulling the entire mass closer to the proper center line of rotation.
Other forces are created, but it has to do with torque or leverage along the center line, but not actual out of balance in the plane of rotation.

If you were in the space station with a perfectly balanced model a flywheel
and crankshaft, and you spun it, it would spin perfectly on the axis of the bearings. If any weight is added it will find a new center line of rotating mass.

The confusion comes in because the counterweight does not have to be directly opposite the area of increased mass to center the rotation.
Many engines have been built with out of balance harmonic balancers,
or out of balance weighted flywheels to counter balance some other out of balance at another point along the rotating mass, the extra tension helps to curb other harmonic vibrations or something like that,,, heck I don't know, I just do it, I never think about it.

That can pose a real problem, or at least a perceived problem when balancing 2 or 3 piece drive lines, built on the ground with no lathe. Then balanced, and I don't mean on a lathe, I mean on the vehicle,, wheels removed and running it up and doing it by hand.
weight added anywhere along the entire mass will affect the entire mass, even with all the u-joints and carriers involved,,, and as such it can be difficult to ascertain exactly where the out of balance is truly at as to get it at that point directly,,,moment of inertia is some strange stuff and I don't get it at all.

But I do play a pretty mean fiddle on certain days.
 
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katy said:
Art, thanks for the explanation on clocking.
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Sure, just some of the things us shade-tree mechanics do.:)

I've read a thread or two about guys that have spent big money on engine rebuilds only to have a lot more vibration than they used to. I've never gotten a response from folk that have high compression heads and how that effects vibration. It would seem to me that when there is a bigger bang in the combustion chamber that there is bound to be more power impulses transmitted to the car. In the article I referenced earlier in this thread he mentioned Ford needing to redesign the motor mounts for 1932 because of the added horse-power of the Model B engine.
 
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