OEM Piston Fact

Ever wonder what that notch that the top of the piston was for?

[blefyplayswowable]

Archaeologists 10k years later: "it was ceremonial"

[AmritGrewal]

"Sound during startup"

- no, they're doing it to increase the *longevity* by reducing piston slap; the sound is just a side effect of piston slap in worn out engines

[lian]

Subaru: Is piston slap a concern to you?
"We dont care"

[Daniel-oygu]

200k mile chevy 5.3l on a cold day: *Diesel noises*

[mannys]

Interesting. I never knew why they were directional. Something very cool about my car's 2ZR-FE engine is that the cylinder bores themselves are offset from the crank away from the thrust side. That means the rod is much more vertical during almost the entire power stroke, reducing side loading and piston rocking considerably. The rod is more sharply angled during the exhaust and compression strokes as a result, but the amount of side load thrust on those 2 strokes is less than that of the power stroke. Since the iron sleeves are not replaceable, this offset design and the reduced egging it provides is appreciated for sure. Less egging means less boring oversize and a shallow honing allows the block to remain usable.

[jakethesnake]

Gotta do the uncle tony move and flip the pistons around for that extra power

[treasurethetime]

Yeah. Exactly what I was explaining to my mother in law over dinner last night.

[CheckUrSole]

YouTube has been feeding me engine building shorts lately I think it’s trying to tell me something 😂

[PiDsPagePrototypes]

Not just that, it also directs more thrust towards the direction of rotation of the Crank, keeping the engine rotating the correct direction.
There's some people who say you can get more power by reversing this, but they never provide any Dyno sheets comparing only this one change.

[pfsantos]

You had me at the covered bolts. A true professional.

[PumpkinKingXXIII]

I think gm forgot to do that on there ls engines, I’ve bought 4 new trucks and everyone has cold startup piston slp

[iknowyourebrokeauto]

It's also there so the valve relief will be on the correct side for larger intake valve

[creed]

I've built atleast a dozen Italian engines and never seen this. Most aftermarket pistons had an arrow towards exhaust whereas original pistons often pointed towards inlet. Sometimes the marking was faint or worn off. A notch is simple idea to avoid any doubt or mistake.

[___Eldritch]

I've been inside a lot of engines man. I've never seen that until this video.

[humblehombre]

Thanks brother. This is extremely in depth and thoughtful info. Nice to see a guy who knows so much, give us the incite we love to hear. Thanks so much.

[MiamiBomber]

Oooh, look at those covers on the connecting rods’ studs

[slantedperspective]

Flip it and the offset will add a bit more power, UTG has a great vidieo on it

[Legally_its_a_joke]

Every 01-06 5.3 gm truck engine laughing in cold start noise

[timdixon]

And for racers out there turn them around on the rod and the piston dwells a bit longer at tdc. This will cause a slight increase in cylinder pressure on the power stroke. More torque is the result.

[saharatransport]

you guys are great. tnanks for all the years of education/entertainment.