Piston Failure Analysis - Skirt Wear

Today, we're going over different examples of piston skirt wear to help you identify what's going on in your engine.

[superbee]

This video help out a lot at 0:25 because I’ve been trying to figure out the problem with alot of Honda 400ex piston skirts were this happens 👍🏻

[dcsymbols]

depends on the the cylinder position too, for instance a flat four engine will obviously wear the bottom of the skirt out faster than the top because of gravity. and also what the vehicle is being used for i.e hill climbs, time attack, rally....

[perrottarober]

I've never seen a piston come out of the bore with the skirt coating completely intact. Even with OEM coatings.

[busdriver]

how much piston scoring is too much? I had a flat tappet cam failure and my Mahle forged pistons are scratched from the debris in the oil. These pistons weren't cheap and I'd like to use them again if possible. Mine aren't as bad as the third piston he picked up, but still have many fine scratches. I will replace the rings.

[aaron___]

2:36 the shape issues wear, is that caused by a poorly performed piston?

[magnusdanielsson]

Im rebuilding a Camaro 3.4 V6 and the pistons in one bank are very scuffed on one side. Why would that be?

[Not-Sure-Viralade-ftw]

what engines are those pistons are they from?, in particular, the fully boxed and braced pistons?

[mjyan]

We have a new piston design which is by splitting the to be operated by a (valvetrain-like) piston-train controlled directly from the crankshaft (including the valvetrain) (see other YouTube). This is called the Differential-stroke cycle (D-cycle) that complete the 4 engine stroke in EVERY crankshaft revolution. This can be done simply by splinting the crown part from its skirt to pump gases during the exhaust and intake strokes and to be supported by its shirt for the heavy compression and power strokes.
The D-cycle is basically a hybrid of the powerful 2-cycle and the cleaner 4-cycle engines. So our car engines can be of 2, 3 or 4 cylinders, instead of current i4, v6 or v8 types. I had worked with MAHLE when developing an e-hybrid for BaymlerChrysler with MAHLE pistons. We are looking for a new partner. Can we talk?

[jefftougint]

At 2:05, if it was a clearance issue. Would it be due to too much piston to wall clearance or to little piston to wall clearances?

[ze_german]

Hi, I am building a Mercedes ALUSIL engine from the mid 90's and the cylinder walls are aluminum that has been polished. Can I get a piston made that would be compatible with this type of block that would prevent galling?

[____MC____]

My wear pattern looks like the second from the left but the finish looks faded since its not worn through yet. Only 500 miles or so and its got oily/gummy carbon residue on top of the pistons. I figure it never seated

[charlesstiles]

So, more clearance means less skirt rub? You would think the piston would rock more with more clearance

[CrizelUmali-splq]

The sleeves or liner is not damage or replace when it comes to piston slap

[stanleyshults]

Also check piston, s for trueness to be round on skirts. From bottom to midway. On

[chouchou]

Does the first ring (top ring)needs to be more clearense then the 2nd ring or contrary . Or which one should be more clearence then the Could you tell me please

[dangerousfreedom]

How much piston to wall clearance should you have 4” bore?

[xredhbb]

nice demonstration, thanks for the video !

[xushenxin]

I am at number 2 from the left. Do I need to replace this piston?

[mattm]

I'm not sure why you didn't say the the skirt being screwed up wouldn't cause oiling issues that's a no brainer that's what it's for and lack of oil in tern can cause the piston to seize in the bore

[waynedoran]

I also have never seen a coated piston coming out of a hole with much coating left on it. Everything from a 1/3 of the coating to almost all the coating gone. I don't buy coated pistons anymore if I can avoid it. There is something to be said about the coating rubbing off and embedding in the cylinder wall providing some extended protection however I have never seen proof of this.