engine and drivetrain About polishing rocker arms

[Guest Anonymous]

Bottom is stock BMW, middle is stock Febi/Bilstein, top is polished Febi/Bilstein. All edges have been removed in order to avoid concentrating stress that could develop into cracks.

[Guest Anonymous]

Better distribution of the load with the Febi parts (left and center), cam side.

Also better distribution of the load with the Febi parts (center and right), valve side.

Underside is also polished. See modified Febi on right. BMW rocker (left) came already polished.

[Guest Anonymous]

URL: http://www.bmw2002faq.com/store/2002books.html

(nt)

[Guest Anonymous]

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[Guest Anonymous]

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[Guest Anonymous]

(nt)

[Guest Anonymous]

Some people will prefer BMW rocker arms at twice the price, but I still feel that Febi have a few improvments over BMW.

[Guest Anonymous]

Aluminum parts under repeted loading are different than you may think. First surface finish unlike steel parts (not cracks) is not significant with aluminum parts. Second aluminum has strength ranges all the way from 10ksi to 75+ksi. The less shine the higher the strength is a rule of thumb. Since the rockers are cast the number of variables for fatigue strength goes off the chart. The casting process with the same alloy ,Which of course we don't know the alloy, can vary + or - 50%. The % elengation at failure from the same cast alloy makes a huge difference in fatigue life and is dependent on the casting process and again we don't have clue from looking at the final cast part what gremlins are lurking inside the part.

I would buy brand name parts from producers with a real history of making the part.

[Guest Anonymous]

(nt)