Starting a youtube channel

[Eggman]

Watch this video on skirt wear from Mahle.

https://www.youtube.com/watch?v=6uK7i4NHuEA

I watched the video, and found it informative. Thanks for posting it.

Rings have a 'back clearance" or "duck under" dimension. .0008" to .0010". Gas pressure behind the ring holds the top ring against the wall and the sealing then is ring to ring land and ring face to wall. The higher and tighter the ring pack is the more stable it becomes. Why? The wrist pin is a fulcrum. The lower face of the piston one contact point and the ring pack the other. Both need a film of oil to slide upon less we scuff the skirt or polish the bore. So, the further those two contact points are the more stable the ring to wall intersection is.

Yes there is a limit. Enough thickness to prevent collapse of the areas between the rings and above the top ring.

Did you know that pistons are both barrel ground, top to bottom and ovate at the center? Shows up when you scuff one,

Attachment 26853

Sorry, I'm not following you here. And that speaks more to me - I'm just not that familiar with the terminology you're using.

[Fummins]

Hop in the comment section of that 524k engine tear video. There's a bunch of people saying the noise was probably lifters, some saying timing chain slap, worn guides and tensioner.

A Mitsubishi dealer tech commented saying it's piston slap and they've seen it a lot(not a direct quote but that's what I recall with my crap memory). I'm with that guy.
I feel dumb now after reading other comments explaining that it's normal to have more wear on one side of the piston, makes sense to me. I just never really diagnosed too many engine noises. If an engine was knocking I'd just replace it with a used one or sometimes a rebuilt or crate engine rather than rebuilt it myself.

That one video took off pretty well! I had 570 subscribers on Sunday afternoon. Last time I checked it was up to 684.

316 more to go then I can quit my day and evening jobs and become a full time monetized lube-tuber!


Planning a camping trip for 2 weeks from now probably where it's cold and snowing. I want to take the van but I still haven't replaced the drone-muffler, it's hard on fuel and I should get new tires...But It's got a heater, I can sleep in it, way more room inside, it's 4wd and it looks cool.

[Grumpy Bear]

I watched the video, and found it informative. Thanks for posting it.

Sorry, I'm not following you here. And that speaks more to me - I'm just not that familiar with the terminology you're using.

Okay, I can work with that. No need to be sorry. We don't know what we don't know. Besides, you set the table for a stone killing two birds. Thanks!

A piston isn't a true cylinder. It's fatter in the middle than at top or bottom, barrel shaped. It's also fatter 90 degrees to the wrist pin than under the pin. As the 3A9* pistons haven't a full skirt the portion remaining is 'cam-ground'. Thus, the wear area is the spot around the fat spot.

Pistons heat unevenly and all this monkey motion of barreling and camming is done so that when the motor is at full heat it's much closer to round than when cold.

Okay, so, in the video you saw that last piston and it showed no wear at all used. That is ideal lubrication, ideal oil selection and ideal OPERATION.

Most drivers are not aware of the role they play in how the motor wears. We are not taught it, and the manufactures have idiot proofed the motor enough to get it past the warranty period well enough as to not become a financial burden. Because this is true and because humans love their anecdotal evidence, we resist the truth that could add years to the motor life. 300K miles / 500 Kilometers is strong evidence indeed. How long do you expect it to last? Right?

Then there is also the practicality of 'doing it better'. Sometimes you just can't.

The photo I showed of a scuffed piston says it 'nipped up' or had many mild partial seizures. And yet the motor did not overheat. Driver never knew it was happening. Never set a code or made a noise.

Most of our modern engines use cast pistons and most of those are hypereutectic. These types are fit extremely tight as they expand very little. But they do indeed expand. Until the motor is fully warmed, summer or winter, the cylinder and piston are 'growing' at different rates. And the piston wins that race always. Heat of combustion is driven via the crown down through the piston until it reaches equilibrium. This happens much faster with LOAD and SPEED. The cylinder, water cooled, takes longer. The oil even longer yet. Only when all three are at full operating temperature does everything play nice together. This is complicated by cold fueling which is diluting the oil as fast as it is applied.

Meaning the warm up is critical. And I'll leave it there.

https://www.youtube.com/watch?v=lCEKJxHiEIM

[Fummins]

Holy, that one video took off a little more than usual. I wonder if that’s Doug that posted the nice compliments that I pinned to the top��
Attachment 26864
Edit: unpinned now. No point giving trolls any extra attention.