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Old 09-22-2019, 10:16 AM
mgarblik mgarblik is offline
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Join Date: Mar 2005
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Quote:
Originally Posted by ponjohn View Post
What does a collapsed piston skirt mean?

It's worn, it suffered trauma?
A collapsed piston skirt is a situation where the lower part of the piston, (skirt) crushes in toward itself in operation. From here, it gets rather complicated. The tendency for a skirt to collapse depends on a huge number of factors. Here are a few: 1. piston material 2. piston head design 3. piston skirt design 4. piston pin box design and support 5. cam grind on the skirt 6. piston skirt strut support and design. 7. oil drainback design in the oil ring groove 8. piston to wall clearance 9. amount of piston skirt that comes out the bottom of bore at BDC 10. piston to rod ratio 11. dwell time at TDC 12. detonation 13. mechanical interference 14. Dozens of other factors.

So it's a complicated series of compromises that go into piston design, machining clearances , and material choice, and application that determine the final outcome.