Originally posted by DemonSVT:
Originally posted by Thinkmoto:
Originally posted by fastcougar:
How many miles TOTAL on the engine? I tend to subscribe to Terry's theory on PM Rod stretch.




On the early 2.5L engines. Maybe.

With how far the technology has come, not a chance. Period!

The same PM style rods support 600-700 wheel TQ in the new Ford diesels.

People indiscriminately claiming PM rods are weak just don't understand the technology and metallurgy behind them. In most regards they are superior to a standard casting of the same design. That's a fact of physics and not an opinion.

Yeah, I'm sure that the rods DESIGNED and SPEC'D for 700 ft/lbs are indeed MUCH Stronger. If you believe that 2.5L and 3.0L gasoline engine rods are made to same specs as 7.0L diesel engine rods are the same, you need to go see a shrink

So, why does the bearing spin? Let's analyse this for a minute if you will. Rod bearings in ALL engines spin for one simple reason ... the forces acting on them overcome the "nip", or bite that they have in the rod journals. Once the bearing has no "seating", it's free to rotate. Now, what causes this to happen is the question.

If you want to believe it's an oiling issue, so be it. I choose not to. Let's just leave it at that and agree to disagree. I'm sure that you will never believe that the PM rod is to blame and I know that I will never be 100% convinced that lack of oil is the issue. So, why beat our heads against a wall?

Just to clarify my use of the term "rod stretch" ... I'm not insiuating that the rods themselves actually strech to any measureable degree. It's more a matter of the notch where the bearing slots into the journal weakens over time and eventually gives way and whalla ... the bearing picks up and spins within the journal. That in turn causes all kinds of nasty things to happen. I for one don't have to worry about this in my rebuild because I taken the necessary precautions (ordered Pauter rods).

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