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Old 10-18-2010, 09:27 PM   #1
340Duster
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Unhappy Balancing pistons/ rods... slightly upset with machine shop

So after having my engine balanced I noticed the machine shop removed metal from one piston from right in the middle at its thinnest spot. Should I be worried by this?
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Old 10-18-2010, 10:46 PM   #2
hot-j
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God Yes!
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Old 10-18-2010, 11:14 PM   #3
MartinSTi05
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That's honestly about the best place to remove material.
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Old 10-19-2010, 01:17 AM   #4
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Man, I don't know about that. You don't want to take material from the area that is going to get the most pounding. Generally they take material off from the skirt insides.
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Old 10-19-2010, 02:39 AM   #5
reddevil
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Well, the only time that is going to fail, is if something is horrible wrong, and at that point it is something OTHER OTHER OTHER than the maching shop doing anything to that piston.

Subaru pistons fail at the edges, 99.9 of the time. I personall have cracked a piston in half but only after burning off a 1/4 of the top edge.

I would not worry at all. Seriously.
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Old 10-19-2010, 10:25 AM   #6
jaxscuby
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Quote:
Originally Posted by MartinSTi05 View Post
That's honestly about the best place to remove material.
normal..

if you also notice there are 2 other holes up near the wrist pin bridges.
removing material to get pistons within a weight tolerance of each other.
when balancing recipication assemblies the weights of pistons & rods
are within a grams of each other.

look at your crank pulley & flywheel
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Old 10-19-2010, 04:12 PM   #7
MartinSTi05
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They drilled many holes specifically to keep the depth/loss of strength to a minimum. I would be worried if there was one hole drilled for the same weight removal;-)
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Old 10-19-2010, 05:06 PM   #8
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I always take away from pin boss area, near the bottom, as it usually has excessive amounts of extra bulk and has little influence on weight side-to-side fo the pin.

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Old 10-19-2010, 05:57 PM   #9
340Duster
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I agree it's probably not a huge issue; just ranting because I feel there are better areas they could have removed material from.
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Old 10-19-2010, 08:47 PM   #10
mtcs
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I'd be worried if they removed material from the piston tops...lol

But you should be fine with what they did.
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Old 10-19-2010, 08:47 PM   #11
john 1badSTI
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they try to do it in the center like that so as to take material off the center mass of the piston.Like they said above it is normal and doesn't weaken the piston really at all.
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