Matt H

Is oven cleaner an effective, efficient method of cleaning the tops of pistons? Will it harm the cylinder walls? There is a ton of buildup and I am trying to find the easiest way to clean it all.
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Sufnituning

Hi Matt.
I got the "Purple power" industrial strength cleaner and I mixed with "Ammonia" and water (Mix ratio 2 part P P 3/4 ammonia 1/2 part water)
I used a little sponge from the kitchen and soak it with the mix squeezed out most and start rub off carefully .
Try only the top and don't let the "special mix:-)" flow down in between the cylinder wahl and piston!!!!! Take your time DON'T RUSHED!!!

Good luck Csaba

Matt H

Problem is I got a little overspray on the cylinder walls when I was spraying the two at TDC and I have to tell you I think this block is trashed. BTW, worked fine to clean the tops of the pistons.
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BoostGuy951

You know Matt, I did the exact same thing. I got some oven cleaner spray on the cylinder walls, and it seemed to create a crusty film which I could not remove. I don't think I really dont think the walls are trashed, I think it just stuck itself to the walls of the cylinder. I put the engine back together and I am in the process of running it a few hundred miles to see if the rings will scrape off and re-polish the cylinder walls. I have not pulled the head off again, but I have noticed that the car seems to run just as well as it did before.

Hope that helps!

Danno

Don't vorry about it! Oven-clean is sodium-hydroxide (NaOH), or lye. It's a strong organic solvent, used to dissolve carbon-based compounds like bodies or crusty-food bits or the stuff off your pistons! It also reduces the oxidation that naturally occurs on the surface of aluminium. That's the natural anodized finish, which is very thin. But it will not dissolve the metal underneath itself, you'll need an acid for that. Since the aluminium is already below the surface of the exposed silicon crystals, you've done no harm. That's also why you couldn't remove the difference in coloring BoostGuy, it's below the surface. Next time, I'd spray some onto a rag first and wipe down the surface of the piston. This will keep it off the cylinder walls.

jdog

Danno,
Has anyone ever told you that you know too much!!
Holy man I feel much more dumb every time you post!!
Jr

Mike S

Now on bare aluminum....that might be a different story. I used oven cleaner on some intake pipes to remove the black anodize from the factory. I had a spare one and left it on there for a day or so...forgot about it to be honest. Well....it etched the surface of the aluminum.....I don't think it did anything structural....but if you left it on there long enough I imagine it could on something thin like a tube.

Matt H

So, I dony need to worry about removing it? i.e. get what I can get off and the piston rings will scrape th rest of it off?
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Alan C.

Sorry to say this but NaOH will go after aluminum. We use it in the lab for weigh strip weigh analysis of weight of aluminum on hot dip coated steels.

However, if the aluminum is anodized it will have little affect on the surface.

The cylinders are etched exposing the silicon crystals but you would be amazed at how much aluminum actually touches the ring. I know because I polished a cross section of a 'well' used cylinder and put it an electron scanning microscope to confirm with EDAX. The area fraction of aluminum surprised me.

Matt H

So Alan, is that a yes?
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Alan C.

Matt,
In my opinion the oven cleaner can etch the cylinders. Depends on how aggressive the cleaner is. Also how much oil was on the cylinder wall. It would tend to dilute the cleaner's effect. Would it hurt the cylinder? Not sure. What I can tell you is that I had a polished mark on one of my cylinders and I etched it prior to assembly. That was 2 years ago and it did not cause a problem.

Refresh my memory, which cleaner did you use and how long/how much did you leave on the cylinder?

Bri Bro

I asked this question to my trusted chemist (father) and here is what he said.

Al will react with "Oven-clean or sodium-hydroxide (NaOH)". Matter of fact, the way that aluminum oxide is extracted from Bauxite is by adding NaOH. This procedure is called the "Bayer Process".
2Al +2NaOH+6H2O = 2NaAl(OH 4) +3H2

NaOH without water will generate Al2O3 (aluminum oxide or Alumina).
2Al + 6NaOH=AL2O3 +3H2O

As Danno stated, Aluminum oxide (alumina white to ivory color) and is very hard to remove chemically. The oxide layer that forms on Al (air +heat) tends to be very thin so it doesn't take much abrasion to get to the aluminum underneath. His recomendation was to NOT use oven cleaner in this application.

Matt H

Everything seems to be okay, a few passes of the clyinders, clean it all out and it appears to be just fine.
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Jfrahm

I was wondering the other day if NaOH would work to expose the silicon after a cylinder hone. It eats aluminum like crazy. I would not get it anywhere near piston sides or a good bore.

-Joel.

Bri Bro

Matt, glad that everything work out.
I think the results are based on exposure time and the amount of Al exposed to the NaOH. I still rely on the advise of my trusted chemist...hasn't let me down to date.