Vibration in an A

[James Rogers]

I spent most of today and yesterday in the shop chasing vibrations in an A motor. Not just any motor but a fresh motor going to a customer in St. Augustene. Not that his motor has anything wrong with it but I see lots of people on here complain about vibration at 45 mph or so or their motor just vibrates and the source is so elusive it escapes the owner.

I tried several flywheels on this motor and got several different amounts of vibration. All flywheels were cleaned in a caustic tank so no clumps were present to make them vibrate. I found that, all stock flywheels would cause vibration. All vibrated at different speeds so, I checked them individually on a crank grinder balancer. All were from 1 oz to several oz. heavy in different places. I installed a lightened flywheel and ran the engine and found it ran beautifully and smooth throughout the power band. This is just another reason to install a lightened flywheel and V8 pressure plate. Even if you use the stock flywheel, it would pay to have it balanced on a dynamic balancer to get it closer to correct.

[1931 flamingo]

Off topic, but my brother and his wife just moved to St Augustine (The Shores) and I will be driving down to visit in a few weeks.
Paul

[Ron/IA]

James - what is your recommendation when balancing; with or without the crankshaft?

Thanks,

[harleytoprock]

James, would you recommend this flywheel set up from Snyder's?

http://www.snydersantiqueauto.com/4665

[Arlyn Bieber]

Here is the procedure used by my balancer. He balances racing engines which turn several thousand rpm so I have confidence in his ability. He balances the crankshaft first then bolts the lightened flywheel on the crankshaft then balances the flywheel then he bolts the pressure plate on the flywheel and balances the pressure plate. Using this system each one is balanced individually and can be replaced without screwing up the balance of the system. This system has worked very well for the sixty plus engines I have had my hands on. Just my thoughts.

[James Rogers]

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Originally Posted by Arlyn Bieber

Here is the procedure used by my balancer. He balances racing engines which turn several thousand rpm so I have confidence in his ability. He balances the crankshaft first then bolts the lightened flywheel on the crankshaft then balances the flywheel then he bolts the pressure plate on the flywheel and balances the pressure plate. Using this system each one is balanced individually and can be replaced without screwing up the balance of the system. This system has worked very well for the sixty plus engines I have had my hands on. Just my thoughts.

So, if you loose a pressure plate or have to replace a component, you have to go through the whole rotating assembly again. I do each piece seperately as modern components are done. That way if one piece goes out I can replace that piece without re-balancing the whole system. You could just replace a broken or worn out part also but, that would defeat the whole purpose of balancing that way. Besides, this is a 3000 rpm engine not a 10,000 rpm racing engine.

[James Rogers]

Originally Posted by harleytoprock

James, would you recommend this flywheel set up from Snyder's?

http://www.snydersantiqueauto.com/4665

Looks like the same system I sell for 425$ no exchange. If a customer picks one up at the shop and trades in a core it is 400$. He may get his from Ron Millers Machine.

[James Rogers]

Originally Posted by Ron/IA

James - what is your recommendation when balancing; with or without the crankshaft?

Thanks,

I guess I answered that in my reply to Arlyn.

[J and M Machine]

https://www.fordbarn.com/forum/album....ictureid=25122
Quote:The original flywheel was well balanced when it left Ford, so how do you figure it went out of balance?

Two examples are resurfacing and replacing the ring gear.

As shown in the picture we always rebalance the flywheel and pressure plate as a unit.
Our balancer is capable of balancing to .1 tenth of gram so the closer to zero the better the engine runs and lasts.
Many customers can attest to the difference of a well balanced Model A.
http://www.jandm-machine.com/balancing.html

[Tom Wesenberg]

Originally Posted by J and M Machine

https://www.fordbarn.com/forum/album....ictureid=25122
Quote:The original flywheel was well balanced when it left Ford, so how do you figure it went out of balance?

Two examples are resurfacing and replacing the ring gear.

As shown in the picture we always rebalance the flywheel and pressure plate as a unit.
Our balancer is capable of balancing to .1 tenth of gram so the closer to zero the better the engine runs and lasts.
Many customers can attest to the difference of a well balanced Model A.
http://www.jandm-machine.com/balancing.html

I often hear the flywheel is balanced to a certaiin gram weight, but at what distance is this? Thanks

[James Rogers]

Originally Posted by forever4

The original flywheel was well balanced when it left Ford, so how do you figure it went out of balance?

Good question. All I have checked or had balanced except 1 have been out of balance and were totally unmodified or drilled after leaving the factory.

[Chuck Sea/Tac]

Good information James. It certainly shows the importance of balancing. Thank you

[Chris Haynes]

A good balancer can move the speed which the vibration comes in. On an A he should be able to move it to a range that you wouldn't use. Say over 5,000 RPM.

[James Rogers]

I have also found, as J&M said, the face of the flywheel is almost always ground out of alignment with the crank center. To grind the flywheel, you must use a ground true center that fits inside the recess for the crank to grind the flywheel face. Most I find have just been placed on the turntable flat and clamped by the center hole and ground. This causes the face to be ground by a surface that is not true to the crank and is, in my opinion, what causes many cases of chatter and vibration.

[harleytoprock]

Originally Posted by James Rogers

So, if you loose a pressure plate or have to replace a component, you have to go through the whole rotating assembly again. I do each piece seperately as modern components are done. That way if one piece goes out I can replace that piece without re-balancing the whole system. You could just replace a broken or worn out part also but, that would defeat the whole purpose of balancing that way. Besides, this is a 3000 rpm engine not a 10,000 rpm racing engine.

James, Do you balance the pressure plate by it's self?
What about if the crank isn't ground true to center and the true flywheel then has the wobbles?

[James Rogers]

Originally Posted by harleytoprock

James, Do you balance the pressure plate by it's self?
What about if the crank isn't ground true to center and the true flywheel then has the wobbles?

I have all my reground cranks checked before using so, the flywheel works great on my stuff. If I sell a flywheel to someone who's crank is ground out of center well,,,, I can't fix that.
And, yes on the pressure plate.

[hotrodalley]

I get confused very quickly.

James, I understand you lighten flywheels 11#

You mentioned Ron Miller. I believe he lightens his 7#

Dan Price's flywheels have been lightened 38#

Bill Stipe makes a 24# aluminum flywheel which is 41# lighter than original

Whats best ?

[James Rogers]

I believe Ron is using the weight difference of the pressure plate. When the flywheel is modified for the V8 plate, you HAVE to remove 11# minimum by removing the raised ring. The V8 pressure plate is approximately 7# lighter than the stock A plate. The best flywheel is the one that suits your purpose best. For everyday driving and stock idling, mine or Ron's is great and I have sold lots for just that purpose. For racing Dan's or Bill's are good and, I have done flywheels that were for racing that were as light as 25#. You have to decide what is best for your particular application and budget.

[Pete]

Just for some general info, a completely stock model A engine can be made to idle at 450 rpm WITH NO FLYWHEEL.
The engine was started with a big drill motor plugged into the crank nose.

I have built several street type model A/B engines using a
12 lb aluminum 350 Chevrolet flywheel and an aluminum 9 inch Long pressure plate.
The reason for the Chev unit? CHEAP, PLENTIFUL and easily modified to fit compared to made for brand units.
The reason most people do this? Better drivability.
A big side benefit, longer engine life due to lower torsional vibration in the crank assembly.

[Kevin in NJ]

FWIW,

At one time it was told to me from a reliable source that more than one NOS flywheel was checked and found to be out of balance. All the flywheels were known to be post A era Ford production.

So a NOS flywheel in a later 30's or 40's box may not be properly balanced.

[harleytoprock]

Originally Posted by Kevin in NJ

FWIW,

At one time it was told to me from a reliable source that more than one NOS flywheel was checked and found to be out of balance. All the flywheels were known to be post A era Ford production.

So a NOS flywheel in a later 30's or 40's box may not be properly balanced.

Maybe, back then, Ford's balancing technology and equipment was not as accuarate as today's.

[CarlG]

The flywheel / pressure plate / clutch disk assembly that I got from Ron Kelley weighs 20# less than the same original assembly.

[J and M Machine]

Originally Posted by Tom Wesenberg

I often hear the flywheel is balanced to a certaiin gram weight, but at what distance is this? Thanks

Tom: Our machine requires you input the radius of the flywheel plus area you are removing from .
With that the machine knows the amount and weighs accordingly for the material to be removed.

See the picture as a stock model A flywheel resurfaced and with new ringear and pressure plate installed. The unbalanced weight at 71.76 grams, then corrected balance weight at .3 tenths of gram @ 4000 RPM. Moving the dynamic to a point beyond the range of normal engine operation.
http://www.jandm-machine.com/balancing.html

[Fred]

Can this be done with the Multi Disc clutch assy. set up ??..

[inex01]

I had my stock flywheel, pressure plate and ring gear balanced and my car now has ZERO vibration at all speeds, it is like a different car and is so much more enjoyable to drive now.

[Bob Bidonde]

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James, J&M,
Thanks for sharing your expertise re dynamic balancing.

[James Rogers]

However you balance the flywheel, it helps. I have a NOS original flywheel that is out of balance and it has never been surfaced or had a clutch on it. I don't remember how much out it is but, it is out.

I have seen the machine Ford used and it was somewhat like the bubble balancers we used to use for wheels. It worked but not like a computerized dynamic balancer of today.

[J and M Machine]

Originally Posted by Fred

Can this be done with the Multi Disc clutch assy. set up ??..

Fred: Yes you can balance the flywheel portion of the multi-disc but not the center section.
you would have to remove the discs from the hub and hub could be balanced separately.