How'd I do /o/
Polishing LS2 pistons.
If they aren't notched then how will the valves have clearance when you put in the high lift cam?
>>14764094
why is there a hole in your piston crown lad?
>>14764094
Is it normal to not have cutouts for the valves?
>>14764119
sometimes, yeah
>>14764119
the relief cuts for valve clearance are known as "fly cuts" and no, not all engine shave them.
I know the 2E-FE engine from toyota doesn't have flycut pistons.
>>14764104
>implying i want to kill my low end street drivability with a shitty cam.
Why the fuck would you polish a piston?
Waste of time.
>>14764108
so when the factory assembles the engine, they can look at the holes to make sure
they installed it the right direction.
the rods also have a little bump on them
it's actually lean manufacturing tips from Toyota.
>>14764108
depends on the car.
LS have mild cams from the factory and don't need Valve reliefs.
>>14764108
speed hole
>>14764227
resistance to carbon buildup and knock.
new pistons come with an (almost) perfect finish, if he's re-using old pistons (look at the hole) then chances are they were coated with crap and needed a good clean/polish.
>>14764108
Weight reduction
>>14764227
several reasons for polishing pistons.
1. reduced surface area for carbon to form.
2. remove hot spots that may cause detonation
3.I'm a bit autistic
>>14764094
While you have them out you should send them to have the domes thermal coated.
Or if you're cheap put some white VHT flameproof on it.
Here's the rest
>>14764271
a guy I know does thermal coatings and anti friction shit for the skirts.
i may or may not even use these pistons and rods
>>14764251
>2. remove hot spots that may cause detonation
Hot spots?
dude the surface not being polished isn't going to cause a hot spot, a tiny burr of metal poking will cause a hot spot, which your piston there does not have.
Also that carbon thing is bullshit, carbon will form and adhere regardless of surface finish.
>>14764311
these pistons don't really have hot spots like an old SBC piston, but the principle is the same.
also, a polished surface is more resistant to carbon deposits
>>14764271
better to do the head, especially the exhaust ports
really helps keep the coolant temps down
>>14764339
>also, a polished surface is more resistant to carbon deposits
Source?
I've polished pistons before and it did nothing to stop carbon.
>>14764372
NASCAR and F1 use near mirror finishes on their pistons.
every major forged piston manufacturer also polishes their pistons before shipping.
those race teams wouldn't do it if it didn't help.
>>14764347
I'm gonna use ZL1/ZR1 heads and those have near perfect intake and exhaust runners.
on an old SBC ya, polishing the exhaust helps a fuc ton.
>>14764396
Just looked up nascar and F1 pistons, none of them were polished ????
>>14764372
You are a real slack fuck mate. Nearly every thread you repeat some absolute nonsensical horseshit then put out your hand and say 'show me I'm wrong, show me, show me.' Look around you and learn instead of appearing a total fool.
Ten seconds in your favorite search engine - http://www.austincc.edu/wkibbe/porting.pdf Page two mid-left.
Twenty seconds - https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/49_2_Philadelphia_10-04_1143.pdf
Carbon and Carbon Black will adhere to a surface with imperfections. Polishing the surface reduces the effective surface area available for the Carbon to adhere to.
Turn your brain on champ, and stop laying the shit on other users when you couldn't wet a tissue in the depth of your mechanical knowledge.
>>14764412
shitty pic but ya, CNC and polished NASCAR piston.
>>14764445
I don't see any polish, all I see is CNC machine finish.
Also for the other 100 pics I've found via google images, CNC finish no polish.
>>14764439
I posted my experience, a polished piston did nothing to prevent carbon formation.
This was my personal experience and why I don't bother polishing anymore.
It's a waste of time.
>>14764454
a proper CNC finish is a polish.
all pistons go through a vibro deburr before being coasted. NASCAR stuff and aftermarket forged pistons are just run through 2 or 3 more polishing steps.
>>14764482
>I posted my experience
>It didn't work for me, therefore it doesn't work.
that shit don't hold up senpai.
>>14764495
Ok, sate your autism and polish the pistons, cya later.
>>14764482
So you fucked a job up, so it's a waste of time for every other application? That's piss poor.
>>14764513
Good, off you fuck with your shithouse attitude.
>>14764279
Slang up some picks of your build man.
>>14764094
>polishing pistons
enjoy your knocking
Lol @ those LS pistons.
11.8:1 compression on this Husaberg I just rebuilt.
Fly cuts in piston, TDC really is at the top of the cylinder... head isn't even really domed.
100hp per litre is love and life.
>>14764528
why did you even start this thread 2bh?
just to show off your pistons?
>hurr durr look at me i have some pistons look at my pistons i'm a real mechanic i have pistons looooool also how do i polish pistons, jk i already know how just needed to start this thread to show i can take an engine apart also i'm gonna polish these because f1 and nascar polish pistons now i will be just like an f1 car hurr durrrrrrr look at muh pistons xdXD xD
Oh wow, I have some pistons too, guess that makes me special eh?
wow man expert mechanic in the house!
>>14764583
Ok it's a little domed.
>>14764589
>Hurr look at me I talk like I know stuff durr
>>14764589
You incompetent fuck, I'm not the OP.
I thought you were off, you cunt.
>>14764640
That's you tho nice projection broseph but nice try anyways my man
>>14764645
I don't care who is who you're both tools.
>>14764589
lol bucket of penis
stop replying to the furfaggot, just report his posts
>polishing piston tops on street engine
>definition of wasting time and energy
>autism level 9000
>>14764583
>mfw my stock ls1 gets 50hp/l
Brah
>>14764659
Report it for what exactly?
>>14764575
that Bait is beyond low quality.
>>14764652
Come on now. You have to face your failure eventually.
Ya tool.
I can see it didn't work for your pistons. Neither did the number two enjoy the overheat.
Tip for next time - Don't lay your cylinder head like that. You never rest on a mating surface.
>>14764094
There is no point to this, right?
>>14764662
>100Hp per liter
so 100 horsepower then
>>14764663
for being a fucking faggot?
>>14764671
>Don't lay your cylinder head like that. You never rest on a mating surface.
It's not laying flat, there are alignment pins in the head that space it off.
>number 2
>implying that's not number 1
>implying you can even tell it overheated
>implying you know anything at all
>>14764694
Number one is closest to the camshaft sprocket, if your manufacturer follows industry guidelines and you aren't so completely useless that you would mix two pistons up.
Number two indicates piston crown overheat. The ring land has also overheated. Doesn't bother me if you don't like this.
Yes, I can tell if a piston has overheated. I am employed to do this, any other things, while floating.
You seem quite upset by the physical, demonstrable and measurable phenomena that Carbon and Carbon black resist adherence to polished surfaces.
Weren't you having a tantrum and leaving a few minutes ago? Can you?
![500_12408_3[1].jpg](https://i.imgur.com/3pwxyz1.jpg "500_12408_3[1].jpg")
>Most advanced piston engineering on the planet is in F1
>Piston crowns not polished
polishing piston crowns on street engine is just like spray painting a dog turd
>>14764716
Don't you have something better to do, like polish pistons?
Lol I should use that as a new way to tell people to fuck off
>go pound sand
>go polish pistons
Both are just as fruitful.
I am not joking, what's the supposed benefit of this? .00001% more complete combustion?
>>14764759
It really has no benefit. For street or racing. Eventually, the engine will be started and used.
>>14764727
Does this generation not? Cosworth CA F1 engine loses approximately nine brake horsepower over 1300 miles, with all of this attributed to carbon buildup on the exhaust valve and piston crown.
>>14764743
You are a strange young teen, I must admit. I do have better things to do in two and a bit hours when I am back on watch. This generator unit is playing silly games with cold starts. I polished these pistons when I rebuild it too, how delightfully wicked. Perhaps you too have better things to do, like pop sick mono's on your two cylinder squid mobile.
>>14764759
>>14764771
Medium to long term retention of as-built power due to the prevention of carbon and carbon black buildup on the exhaust valve and piston crown. This is not to prevent a thin layer of carbon adhering to the surface. That is going to happen regardless of the finish or coating.
>>14764727
god damn that looks lightweight
Set them on the Lapmaster and go have a beer.
Then finish them on the polishing stand with some .3 micron paper.
It'll be like looking in a mirror.
If not available, substitute all of the above for good quality paper on a glass plate. Go slow with no added downward pressure.
>>14764782
>Medium to long term retention of as-built power due to the prevention of carbon and carbon black buildup on the exhaust valve and piston crown. This is not to prevent a thin layer of carbon adhering to the surface. That is going to happen regardless of the finish or coating.
I am confused.
>black buildup on the exhaust valve
How does polishing the piston prevent build up on the exhaust vallve? Or you mean if you polish the valves too?
>>14764821
If the carbon is able to adhere to the piston crown it allows light carbon produced by the power stroke to bond to the surface of the crown. See >>14764589 for medium to heavy build up on the number two piston crown (the left one for Mrcummy).
This buildup occurs until the carbon can break from the piston crown in a small lump. These thick deposits of carbon settle on the back side of the exhaust valve increasing the impedance to the flow of exhaust gas. It also settles within the exhaust runner and manifold further increasing the impedance. Polishing the exhaust pocket, runner and manifold yield medium to long term results retaining as-built power over time.
The backside of the valve can indeed be polished which will aid in resisting the buildup of carbon but if clag is coming out through the exhaust valve it will be hard to shed these deposits, especially at low exhaust gas velocity.
>>14764876
Good explanation, cool.
>>14764894
No worries man, have a good one.
>>14764899
shop, pixels, etc
>>14764222
this.
the only thing i'm woried about is carbon build up in that small recess in the corner.
>>14764589
I agree with you. this isn't a blog, no one here cares that OP can polish pistons
>>14765423
That's funny, coming from a Honda enthusiast. Can you find the right direction to turn the bolts for your bolt-ons?
>>14765423
Pot. Meet kettle.
http://archive.4plebs.org/o/search/tripcode/%21NBld.TdwUs/
>>14765516
with a few simple mods I can chop anything you throw at me, as long as it's from a rolling 20. If you'd like I could start making threads about it for you :]
>>14765547
90% of my trip posts are in /hg/ containment threads, I dont make threads blogging about how I can clean my headlights or polish my alternator.
>>14764583
What does it redline at?
>>14765563
The few simple mods meme is a bit old kiddo.
Cleaning headlights compared to surfacing an internal component? wew lad, fitting the Honda stereotype there. I suppose everything looks as easy as polishing your alternator when you've never opened an engine.
Why polish them? I would sand the sharp edges around the valve cut outs a tiny bit (not your pistons but for others) also the sharp edges on the head. This will greatly reduce the chance of knocking.
Sand the tiny hole a tiny bit so its not a razor sharp edge
>>14764583
>not getting 180 hp/L
>not living the 2-stroke life
>>14764104
>having an interference motor
Fuck that.
>>14764652
Why that fox tryna catch the dick
>>14765578
Rebuilt a few engines both during and outside of work/college. Just because I currently own a shitbox honda doesnt mean I'm ignorant or inexperienced when it comes to automotive..
It's great that OP is posting content relating to /o/ but this thread doesnt seem to have a purpose, like cummy said.
>>14765699
> Hands on anon doing work
> Good info with source
> No purpose
Really man? Not OP, but it was on track until you and your friend's efforts. I see ignorance and anime come as a package deal.
Your ownership of a Honda is nothing, what you drive is completely up to you and if it ticks the boxes for you, awesome. You are complaining about threads turning into blogs about auto by turning a thread into a blog, about you.
Don't you and your mate cuminme already have a super secret auto club where you don't discuss anything automotive in /hg/?
>>14765756
sorry for derailing what you've got going on, I'll slither back to my containment thread of fixing shitboxes
>>14765782
Nice one. Enjoy the respray if you still got that going on.
>>14764094
>polishing
Needs more shine. Should look like fucking chrome m8.
>>14765976
i'll try.
So if I got this right, you wet sand them with really fine grit, then maybe some pastes, until it's really shiny? Exposed to heat, fuel, air and constant explosions; how long does something like this last?
>>14764589
I enjoyed seeing a picture of OPs pistons. Fuck you.
>>14765620
>not getting 300 hp/L
>not living 4g63 life
>>14766633
fuck that
just used black rouge polish followed by white rouge with a buffing wheel.
>>14766653
but ur pistons are ugly and have shitty Subaru square designs.
mine are shiny
and dont melt ring lands.
>>14764589
but ur pistons are ugly and have shitty Subaru square designs.
mine are shiny
and dont melt ring lands.
>>14765566
Husaberg doesn't have a rev limiter.
It's a race motor, I'd say keep it under 9k rpm.
>>14765630
What a silly thing to say.
>>14770429
'Merica, he can't into performance.
>>14770439
Miatas are non-interference.
>>14764279
well done, could be truly mirrored but not bad at all man.
>>14764589
> boy....
>>14764589
This is why /o/ sucks. Here this guy is, actually posting OC and having a mature and informational conversation about it, and these tripfags come in and give him the business, fuck this place.
