4.0 Rod Bearing Size
10-10-2016, 12:05 PM
#1
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Year: 1999
Engine: 4.0L
4.0 Rod Bearing Size
Hey I've been over in the New Pistons thread, but had to start a new one to get help on a different question.
My Rod Bearings are different.
Top: Standard
Bottom: .001
The top bearings are all worn more. right at the top and middle of each bearing.
Considering the wear on the Standard Tops, I'm worndering which bearings to buy.
Should I express order a set of .001 undersize real quick? Or standard?
My Rod Bearings are different.
Top: Standard
Bottom: .001
The top bearings are all worn more. right at the top and middle of each bearing.
Considering the wear on the Standard Tops, I'm worndering which bearings to buy.
Should I express order a set of .001 undersize real quick? Or standard?
10-10-2016, 08:24 PM
#3
Old fart with a wrench
Yeah, the top shell always wears more from the pressure of combustion. All the bottom shell does is contain the rod from centrifugal force. Think about it. At idle, the pistons change direction every .04 seconds.
Last edited by dave1123; 10-10-2016 at 08:29 PM.
10-12-2016, 11:27 PM
#4
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Year: 1999
Engine: 4.0L
I like the math there Dave. That's a good way to look at it. When the piston goes boom its gonna slam that top bearing. Never really thought about Rod Bearings in detail like that.
10-13-2016, 04:29 AM
#5
Old fart with a wrench
If you're really interested, think about the inertia stress on pistons at, say, 3000 rpm! You begin to wonder how any engine stays together for long. We've had over 100 years to design something better and we haven't done it. Well, we have if you consider turbines. They are fuel hogs.
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