Question about x rods

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Dan Hatch
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Question about x rods

Post by Dan Hatch » Wed Jul 29, 2020 10:35 am

Can anyone give pros or cons of x rods? I have a set of A x rods I am thinking about putting in a T with a Scat stroker crank. Are they any better than a standard rod. How about strength, Any weaker or what. Got to be a reason Henry when to them in late T run and kept them into A run. Why did he so back to a reg rod? Price only? Let me know what experience anyone has had. Thanks Dan

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Henry K. Lee
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Re: Question about x rods

Post by Henry K. Lee » Wed Jul 29, 2020 10:40 am

They only help in my opinion Dan.., been using them way over 25 years plus!

Hank


Kevin Pharis
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Re: Question about x rods

Post by Kevin Pharis » Wed Jul 29, 2020 5:55 pm

‘Ol man Ford changed a lot of things for for a lot of reasons during his reign... but rarely did he change to a design that reduced reliability. However, the X rods showed up 14+ million cars into T production, and were phased out in a relative “blink of an eye”. Half of ‘27 thru half of ‘28 is all they lasted for Ford, and as far as I know... never to be seen again... by any manufacturer... ever! Leads me to believe they weren’t all they were cracked up to be...? 🤔

I know they are lighter than the H beam rods... and they don’t put up much of a fight when it’s time to straighten. But in all fairness... I’ve never seen, or heard of, a broken one

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Henry K. Lee
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Re: Question about x rods

Post by Henry K. Lee » Wed Jul 29, 2020 6:53 pm

The cost in the manufacturing process I believe is why they left in a hurry. Henry always want more nickels in HIS pockets.


Kevin Pharis
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Re: Question about x rods

Post by Kevin Pharis » Wed Jul 29, 2020 7:36 pm

I fully agree that cost would have been a major factor in the X rod changeover decision. X rods were lighter, and therefore would have had a lower material cost. But I don’t suspect the cost of manufacturing would have been significantly different. They still required forging, machining, and babbiting in the same manner as the I beam rods did.

My personal suspicion... is that an X rod equipped engine might be more prone to harmonic vibrations, or even crank breakage vs. an I beam rod engine.

Explanation... reducing the reciprocating and rotating mass of an engine is rarely a bad idea... but with a massive flywheel on the back of the crank and none on the front (harmonic balancer), connecting rods with less rigidity will “allow” the crankshaft to deflect and therefore causing harmonic vibrations. I am in no way claiming that the I beam rods in a T are “rigid”, just simply “more rigid” than the X rods. In the era, Hispano Suiza (Hisso) and Miller race car engines had steel tubular rods. Modern engines keep the rods light and rigid with steel H beam, billet aluminum, and titanium designs. Even with the incorporation of harmonic balancers, rod rigidity is still an important part of reliable engine design

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Henry K. Lee
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Re: Question about x rods

Post by Henry K. Lee » Wed Jul 29, 2020 8:04 pm

Kevin,

My Mistake, I was under the impression Dan was referring to X rod in X grooving the inside babbitt. Can I blame it on the heat today?

Me Bad Dan! Yes, as Kevin stated, Heavy in Rotation. big power sucker.

Hank

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