The Ford Barn

russcc · 05-28-2019, 07:20 AM

The rotating assembly in the 59L block was balanced, but we did not have the front crankshaft pulley at that time. I have a good used one that has what appears to be balancing holes drilled in the fan mounting flange. I would like to balance the pulley. Any suggestions on how to mount it on the balancing machine ? The shop that did the balancing has been trying to figure out how to mount it. Thank you Fordbarners.

alanwoodieman · 05-28-2019, 08:09 AM

should have been mounted on crankshaft you are using, do you happen to have access to another crank? or a short shaft could be made up to mount this pulley to while balancing, to be honest, I doubt it will matter as you have said it appears to have been balanced at the factory

drolston · 05-28-2019, 08:58 AM

Imbalance in a crankshaft pulley, being relatively low mass and small diameter will not cause perceptible vibration. The crank mounted fan, on the other hand, needs to be balanced and checked for straight blades.

Lay the fan on a flat table and be sure all blade leading edges touch the table all along the radius. I was in the habit of using the fan blades on my '41 to rotate the engine until I discovered that those blades bend easier than you might imagine.

A belt driven fan is not very important to balance because the belt dampens any vibration.

russcc · 05-28-2019, 01:33 PM

Thank you. Good point about the crank mounted fan as well as the pulley.

Pete · 05-28-2019, 03:17 PM

Quote:

Originally Posted by russcc

The rotating assembly in the 59L block was balanced, but we did not have the front crankshaft pulley at that time. I have a good used one that has what appears to be balancing holes drilled in the fan mounting flange. I would like to balance the pulley. Any suggestions on how to mount it on the balancing machine ? The shop that did the balancing has been trying to figure out how to mount it. Thank you Fordbarners.

First off, you need to find a different shop to do your balancing.
If they can't figure out a simple job like that, they shouldn't own a balancer.

You have several options.
1- Make an arbor that fits the pulley.
2- Use a tapered expandable arbor.
2- Take your crank out of the engine and re-do it with the new pulley. (Least desirable method due to the work involved).

After doing the pulley, mount the fan on it and balance it. DO NOT take any material off the pulley to balance the fan. Check the fan for runout before balancing.

It is not practical to use another crank because you would have to balance the other crank before mounting the pulley on it. That would involve bob weights and that is not practical, costwise.

supereal · 05-29-2019, 11:17 AM

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We balance lots of cranks at our shop as part of the grinding and polishing procedure, but not the crank pulley. If you believe you need to balance the pulley for a periodic vibration, it is more likely some other rotating component.

russcc · 05-29-2019, 06:41 PM

The shop did balance a pulley with the crank, but that was before I decided to but the 59L in the '40 coupe, which has a different pulley. I will get both the pulley and fan balanced as Pete suggested.

rotorwrench · 05-30-2019, 02:27 PM

If a person can set up a shaft as a mandrel for the pulley, it can be static balanced. A person could use a lathe to make a mandrel. I have a modified $75 motorcycle wheel truing and balancing stand that would work.

The front pulleys are not very wide so they don't affect balance much but when you add a fan that changes things. You also have to make sure the fan tracks well. If it has a bent blade that is out of track with the others then it will cause a vibration on a different plane.

I used to balance turbine & compressor rotors years ago on a Balreco machine. Now days I just balance main & tail rotors plus engine cooling fans with the old Chadwick Helmuth rotor balance equipment.

05-28-2019, 07:20 AM	#1
russcc Senior Member Join Date: May 2010 Posts: 2,871	Balancing a '40 crankshaft pulley The rotating assembly in the 59L block was balanced, but we did not have the front crankshaft pulley at that time. I have a good used one that has what appears to be balancing holes drilled in the fan mounting flange. I would like to balance the pulley. Any suggestions on how to mount it on the balancing machine ? The shop that did the balancing has been trying to figure out how to mount it. Thank you Fordbarners.

05-28-2019, 08:09 AM	#2
alanwoodieman Senior Member Join Date: May 2010 Location: upstate SC Posts: 2,963	Re: Balancing a '40 crankshaft pulley should have been mounted on crankshaft you are using, do you happen to have access to another crank? or a short shaft could be made up to mount this pulley to while balancing, to be honest, I doubt it will matter as you have said it appears to have been balanced at the factory

05-28-2019, 08:58 AM	#3
drolston Senior Member Join Date: Jun 2014 Location: Williamsburg, VA Posts: 1,627	Re: Balancing a '40 crankshaft pulley Imbalance in a crankshaft pulley, being relatively low mass and small diameter will not cause perceptible vibration. The crank mounted fan, on the other hand, needs to be balanced and checked for straight blades. Lay the fan on a flat table and be sure all blade leading edges touch the table all along the radius. I was in the habit of using the fan blades on my '41 to rotate the engine until I discovered that those blades bend easier than you might imagine. A belt driven fan is not very important to balance because the belt dampens any vibration.

05-28-2019, 01:33 PM	#4
russcc Senior Member Join Date: May 2010 Posts: 2,871	Re: Balancing a '40 crankshaft pulley Thank you. Good point about the crank mounted fan as well as the pulley.

05-29-2019, 11:17 AM	#6
supereal Senior Member Join Date: Jul 2014 Location: Iowa Posts: 1,634	Re: Balancing a '40 crankshaft pulley Sponsored Links (Register now to hide all advertisements) We balance lots of cranks at our shop as part of the grinding and polishing procedure, but not the crank pulley. If you believe you need to balance the pulley for a periodic vibration, it is more likely some other rotating component.

05-29-2019, 06:41 PM	#7
russcc Senior Member Join Date: May 2010 Posts: 2,871	Re: Balancing a '40 crankshaft pulley The shop did balance a pulley with the crank, but that was before I decided to but the 59L in the '40 coupe, which has a different pulley. I will get both the pulley and fan balanced as Pete suggested.

05-30-2019, 02:27 PM	#8
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,436	Re: Balancing a '40 crankshaft pulley If a person can set up a shaft as a mandrel for the pulley, it can be static balanced. A person could use a lathe to make a mandrel. I have a modified $75 motorcycle wheel truing and balancing stand that would work. The front pulleys are not very wide so they don't affect balance much but when you add a fan that changes things. You also have to make sure the fan tracks well. If it has a bent blade that is out of track with the others then it will cause a vibration on a different plane. I used to balance turbine & compressor rotors years ago on a Balreco machine. Now days I just balance main & tail rotors plus engine cooling fans with the old Chadwick Helmuth rotor balance equipment. Last edited by rotorwrench; 05-30-2019 at 02:33 PM.