Thoughts on ultrasonic cleaning pistons

[pampadori]

Generally speaking, will an ultrasonic remove the iron coating on these pistons?
If I plan to use them with freshly nikasil plated cylinders, is that going to be a problem? I understood it was mainly applied to deal with the alusil cylinder properties.

How thick is this coating and will the pistons be much smaller in diameter if it is removed?

Just wanting to make sure I don't ruin something if I can prevent it.

[smokintr6]

I used the ultra sonic cleaner at work on my 3.6 mahle pistons. It completely sucked. It made almost no difference in the baked on carbon. After reading on the internet, people have much better luck soaking in a warm simple green and water solution. Another friend at work used simple green and water on his kitchen stove, and laughed at me as the carbon wiped right off his pistons... D'oh. Other results online show the ultrasonic cleaner effective if the parts are left in for 24 hours. the same threads contained speculation that just sitting in the warm cleaning solution for 24 hours probably would have worked even if the ultra sonic part wasn't turned on. I have had astounding results on things that are cad plated, or "shiny" in the sonic bath.... Pistons, not so much.

[pampadori]

Tested it out on one piston this evening. About 15 minutes in a heated solution of water and purple power. They certainly do look different. And I don't know if I'm seeing a chemical reaction or something else there on the channel where the oil ring resides. It started out much cleaner looking there before the ultrasonic, but much darker there afterwards. Wonder why that is?



Also took some side by side pics of the 8.5 and the 9.3 95mm CIS pistons. Might be helpful in the future for someone trying to compare the two.

[Tippy]

I believe most of those chemicals are either caustic or acidic. Aluminum probably formed a barrier of corrosion to protect itself. I only use solvents.

[reclino]

Try aircraft paint stripper on the pistons. I soaked mine in a small tub of it for about 2 hrs and the carbon wiped right off.

[Tippy]

I just soaked mine in diesel, and the carbon came right off

[Dpmulvan]

Don't use purple power on Pistons !!! It's caustic. Ultrasonic cleaning works very well if you have the right chemistry, unfortunately it's pricey that's why my ultrasonic cleaner is on the shelf.

[JFairman]

Don't use alkaline based 409, Simple Green, or Purple Power on anything aluminum. They all slowly eat aluminum.

I've soaked pistons crown side down in aircraft paint remover for a few days and it softened the carbon but it still took some scrubbing with red scotch brite pads or steel wool and solvent to get it all off.

Wrap the sides of the pistons with a couple layers of masking tape and bead blasting or soda blasting would probably work well on the crowns.

[Tippy]

Overnight soaking in diesel followed by a little brass brush cleanup before and after:

[pampadori]

Any thoughts on why that one ring land reacted so differently than the rest of the piston?

[SCadaddle]

Originally Posted by pampadori

Generally speaking, will an ultrasonic remove the iron coating on these pistons?
If I plan to use them with freshly nikasil plated cylinders, is that going to be a problem? I understood it was mainly applied to deal with the alusil cylinder properties.

How thick is this coating and will the pistons be much smaller in diameter if it is removed?

Just wanting to make sure I don't ruin something if I can prevent it.

My KS Alusil pistons were soaked in individually marked tin cans (think non perishable food storage here) filled with acetone for a few days. Light scrubbing with a toothbrush in the ring lands and very fine green scotchbright dipped in acetone cleaned them up well.

EBS Racing plated my KS cylinders with Nikasil and supplied the rings for my original KS pistons and my engine has surpassed 10k miles with very very little oil use and hasn't yet blown up. Would I go this same route of Alusil pistons in a Nikasil plated cylinder again? No, I probably wouldn't in hindsight. It is too controversial and you must consider that my success story is only one data point when it comes to such "mis matching" of components.

The Maestro being the Late Great Harry Pellow of 356/912 engine fame preferred to clean everything in the dishwasher with HOT water if the wife wasn't around to find out.

[hcoles]

Originally Posted by Tippy

I just soaked mine in diesel, and the carbon came right off

I've heard this before. If nothing else, easy and cheap to try it and should not damage the surfaces.

[Tippy]

Originally Posted by hcoles

I've heard this before. If nothing else, easy and cheap to try it and should not damage the surfaces.

I also bought a $3 5-gallon bucket with sealant lid from Home Depot to hold the diesel and parts.

<$10 parts washer!

[chris_seven]

As long as you use a Goetze ring pack which is compatible with Nikasil the Iron Plating shouldn't really cause any problems.

Don't use KS Ring packs for Alusil Bores they just aren't compatible.

There was also a boundary layer of Tin used when the pistons were new.

You probably have two chances to successfully remove the iron layer - slim and none

They were plasma sprayed with iron so adhesion is excellent.

I believe if the rings are OK then the iron plating shouldn't be much of an issue.

Expansion shouldn't be an issue as cast pistons are generally around 12% Silicon which is virtually identical to Mahle 121 which is the alloy used for forging.

Alusil pistons in Nikasil Cylinders

The last post is worth reading and it f were my engine I would give it a shot.

[AVI_8]

Can someone explain why diesel seems to work really well going by the pics above, I would have thought that petrol would have worked better,?
I'm not doubting what your saying, just that petrol has always been my preferred de greaser and almost seems to work like a solvent, whereas diesel is more oily