Are You Demagnetizing Your Connecting Rods?

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dibbons

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Today when I picked up my Mopar 340 connecting rods after having the rod bolts replaced and big end reconditioned at a Mexican diesel machine shop, I was told six of the eight rods required demagnetizing. I was not aware of this procedure prior to today.

 
And how much did they charge you for that?
 
Maybe they had been magnafluxed?
And should have be de-magged post inspection. But when in Mexico…

You use the same magnet to Mag and de-mag the part. It’s all in how you zap the part. Zapping in one place magnetizes and passing as in the video above de-magnetizes.
 
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That’s not fair.
Shop just said that they did demagnetize rods and did not charge him.

Most shops here would not even mention it.

Maybe because they don’t do it.
 
That’s not fair.
Shop just said that they did demagnetize rods and did not charge him.

Most shops here would not even mention it.

Maybe because they don’t do it.


Yup. Most shops don’t have a wet mag. You damn sure need to demagnetize when you are done checking for cracks.
 
So who has something big enough to demag a block? This is horse hockey.

I saw a wet mag big enough to do a block but it was at an Air National Guard base and that was probably about 1975.

We took a field trip to the base. They had all kinds of cool stuff there. And probably some very cool stuff we didn’t get to see.
 
Today when I picked up my Mopar 340 connecting rods after having the rod bolts replaced and big end reconditioned at a Mexican diesel machine shop, I was told six of the eight rods required demagnetizing. I was not aware of this procedure prior to today.


It's interesting that they mentioned demagnetizing the rods. It’s actually a common procedure, especially after machining processes like reconditioning or replacing bolts. During those operations, metal parts can become magnetized, which could potentially interfere with certain measurements or cause issues with the engine’s performance down the line. Demagnetizing ensures that the rods are free from any unwanted magnetic fields that could affect things like bearing clearances or even fuel injection systems in some cases. Definitely a good thing to do, even if it’s not always talked about.
 
It's interesting that they mentioned demagnetizing the rods. It’s actually a common procedure, especially after machining processes like reconditioning or replacing bolts. During those operations, metal parts can become magnetized, which could potentially interfere with certain measurements or cause issues with the engine’s performance down the line. Demagnetizing ensures that the rods are free from any unwanted magnetic fields that could affect things like bearing clearances or even fuel injection systems in some cases. Definitely a good thing to do, even if it’s not always talked about.
This is all foreign to me. I've had many rod sets reconditioned (new pin bushings, rod bolts, and resizing) and have never had a shop demagnetize them or even mention it. A couple of the motors I then tore down after many, many miles, none of the rods looked like they had been shake and baked. Am I just lucky?
 
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