What should pistons look like?

[GeoffM]

I remember doing my plugs and plug seals last spring. I peered down the holes and the pistons looked like they were rusted. Is that normal?

[C91BLX7]

They should look black/metallic black.

[C91BLX7]

fuck those are big.

[deevergote]

Pistons are aluminum... they don't rust.


They're also insanely light. Shocked me the first time I picked one up.

[Straight Success]

H22 and F22 are small compared to many others I've seen. Motorcycle and dirt bike pistons are even smaller, depending on motor size.

They should look like carbon caked and covered saucers with possible burnt metal blemishes (hot spots) depending on the condition of the engine.

EDIT: Just type in used pistons in Google search, and look at the images.

[GeoffM]

The attached images seem about right. I could only see through the spark plug hole and had limited light.

I don't think all pistons are aluminum. I picked up one today and it seemed about the correct weight for steel.

[Straight Success]

http://www.hoon.tk/tech_tips/pistons.html

If you ever hear someway say they have forged pistons, it usually refers to forged aluminum.

[GhostAccord]

The top pic of the BHB piston looks like a screw dropped into the intake and went for a bounce around the combustion chamber for a little bit.


To be honest. There has to be over 100 build threads around with members showing their engine with the head off during the tear down.

New on the left old on the right, you can see a bit of wear on the skirt, aka side load.


Here is what most good running 200k+, 8.8:1 compression piston tops would look like. There is an area of light brown around the edges, same as the carbon on the insulator of a spark plug.


This is what they should look like

[GeoffM]

The top pic of the BHB piston looks like a screw dropped into the intake and went for a bounce around the combustion chamber for a little bit.


To be honest. There has to be over 100 build threads around with members showing their engine with the head off during the tear down.

New on the left old on the right, you can see a bit of wear on the skirt, aka side load.


Here is what most good running 200k+, 8.8:1 compression piston tops would look like. There is an area of light brown around the edges, same as the carbon on the insulator of a spark plug.


This is what they should look like

I noticed the scratches. I just ignored them.

I have no way of telling what the sides look like. When I did my oil pan gasket the underside of my engine looked orange/greenish.

The pic of the pistons in the head looks about right. The one on the right looks like it has more carbon than the rest though. Would fuel injector cleaner help restore them?

And I'm pretty sure that your number 3 pic changes as soon as they start firing

[Straight Success]

... the one on the right looks like it has more carbon than the rest though. Would fuel injector cleaner help restore them? ...

I think the piston on the right has more build up due to uneven detonation of air/fuel in each cylinder (very minimal though). Over the course of x amount of years or miles, every cylinder has experienced very slightly different conditions than the next cylinder. Over time, the cylinder on the right is the result.

I'm honesty not sure. I know it usually destroys deposits in the fuel systems, injectors, and EGR system. I'm not sure if it would aid with cleaning of the tops of the pistons. I'm sure some will post it though.

[GhostAccord]

And I'm pretty sure that your number 3 pic changes as soon as they start firing

Nah...... That's why I polished them and the combustion chambers. To reduce heat and carbon build up. It should take a wile for them to show any signs. They will never look like those stock pistons.