Engine Balance, some more details...

K

Kevin in NJ

Well-known member
Questions on just how far Ford balanced the engine come up once in a while. I have never had numbers for the piston tolerances. It seems those numbers have been under my nose, I just have not looked hard enough.

From
http://www.modelarestorers.org/main/index.php?option=com_content&task=view&id=59&Itemid=426

You will see Ford matched the whole connecting rod piston assembly to 3.5 grams. The rods were allows a gram on each end.

Keep in mind that at least one major rod shop does the rods only to 5 grams total weight. I have measured non-Ford pistons to be off by as much as 50 grams in a set.

The original Ford engine work was pretty special.
 

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I got the same message as Vince.

My original Ford literature says the following:

Connecting rod - balanced to within 2 grams. Total weight held to within 4 grams of limit.

Pistons - total weight held to within 4 grams of limit.

Piston assemblies - must match in weight within a limit of 3 1/2 grams.

Piston pin and pin hole - diameter held to within .0003 of an inch.

Crankshaft - must balance dynamically to within 4 grams.

Main and connecting rod bearings - held to within one-quarter of one-thousandth of an inch of true roundness.

Crankshaft bearing alignment in engine block - held to within one-half of one-thousandth of an inch of absolute true.

Brake drums - held to within ten one-thousandths of an inch of total diameter.

And some people say, "Well they didn't even know what a torque wrench was back then ...... guess that ol' Model A was just thrown together."


Henry Ford came out and said, "Now don't drive that thing over 45 'cause it might just come all to pieces!"

:0)
 
forever4 said:
Well that sucks.
Even though I am a MARC member, I am unable to view your link, only the notice that says:
"You are not authorized to view this resource.
You need to login."

But there is no login screen?????
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It is the last item on the left under member section. You can click it below if you like.

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those rod sets that are matched with 5 grams still need major rework the difference at the big and small ends are usually significant. i get them within 1 gr at each end and end result is perfect matched in overall weight. ive found new piston sets to be pretty good requiring only minor stock removal from the pin id to match them up. the factory had a large assortment of stock to sort and get the best matching components
 
The factory did not sort through parts and match them.

They were machined to certain weights. It would take too much time and labor to sort and match. Ford based production on precision manufacturing.

For example, the rods were required to be a certain weight at each end +- 1 gram. So during production you just grabbed any 4 rods and put them in the engine.

They had machines that measured the weight and cut off enough material to get the required weight and stopped automatically.
 
jetmek, what motivated you to choose such a name for your business?

When I first looked at your web address I thought it said "god evil" but when I went to the site it is "Go devil."

Neither one would inspire me to favor you with any business.

Just my opinion.


Larry B.
 
thank you for the kind words. my company name simply infers that my engines "go like the devil" its my opinion that public forums are no place for misguided opinions!:D:D:D
HoarseWhisperer said:
I believe I met jetmek at the show in Stowe, Vermont.

He appeared to be honorable, knowledgeable, and without condescension.
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