Cleaning piston tops

[TominMO]

I've been cleaning off my piston tops with brake cleaner sprayed onto a paper towel, and gotten them fairly clean; but there is a caked-on deposit of oil on three of the pistons that isn't coming off. It isn't really a problem, but I would like to get them completely clean. Is there a good, non-scratching brush for Dremels or drills that we can use to clean the tops of aluminum pistons? Obviously I don't want to scratch them. Is copper softer than aluminum for instance, or do I need to find a plastic bristle brush?

[gergorian]

A brass brush might work. But it has a Brinell hardness twice that of Aluminum according to this http://www.drill-hq.com/2011/11/hard...ous-materials/. Although Copper is softer than aluminum but it is probably also softer than the material you are trying to remove.

[shadetree]

Acetone soak for three hours ,scrub gently with brass bristle brush then finish up with soapy water and a plastic bristle brush . Works great . Passing along Advice given by Advancedynamics .

[gergorian]

One thing you could also do is get a cheap ultrasonic cleaner from Harbor Freight ( I have one and I love it).

[TominMO]

Thanx for all the kwik replies guys!

[red90festyonair]

I have always soaked them while in the mid stroke position with wd40 or pb blaster. I spray enough to create a pool shallow enough to submerge the piston tops. Leaving sit at least overnight. The next day or two later the gunk will be dissolved in the pool. This can be then cleaned up with a simple rag. The buildup is normally petroleum and carbon so it can be diluted with most penetrating oils. My grandpa used to use 3 in 1oil but I am not sure that it is even still available...

[scitzz]

You can still buy 3 in 1! Love that stuff!

[Advancedynamix]

Boiling hot water, with a teaspoon of dawn dish soap and a firm bristled nylon brush. This will clean the stubborn black residue without removing precious piston material.

I actually boil my pistons on the stove in the kitchen. Yes I'm a bachelor. Haha

[Movin]

Throw them in the 5 gallon berryman carb cleaner, they come out like new with no scrubbing, just rinse.

[jbibb1]

Useless bit of information . . . . anytime you want to know which of any two materials is softer . . . . rub them together and whichever material receives the scratch from the other material is the softer of the two . . . that is all

[Advancedynamix]

^^Yeah, that works too. You could probably soak them one at a time in the little gallon can if you don't want to commit to the big one.

[TominMO]

Throw them in the 5 gallon berryman carb cleaner, they come out like new with no scrubbing, just rinse.

Pistons are still in the motor; but I'm getting the idea that all sorts of solvents, left on overnight, will do the trick.

[TominMO]

Boiling hot water, with a teaspoon of dawn dish soap and a firm bristled nylon brush. This will clean the stubborn black residue without removing precious piston material.

I actually boil my pistons on the stove in the kitchen. Yes I'm a bachelor. Haha

Are you a bachelor because you did this, or were you one before?

[blake4591]

I always use B12 chemtool for cleaning pistons and combustion chambers. It is available at most box stores and is advertised as a fuel system adative. It will melt carbon deposits in minutes but you need to wear good gloves and safety glasses because it will burn you if you get it on your skin for anytime.

I talked to one of my chemical engineering friends about it once and he said the active ingredient in it will melt the special nonreactive containers they use, if store undiluted.

[TominMO]

Went out and tried a buncha things I had laying around:

Piston #1: Simple Green. This piston was pretty clean anyway.
Piston #2: WD-40 Penetrant (yellow top, similar to PB Blaster but without the noxious smell; NOT the old red-top variety of WD-40)
Piston #3: brake cleaner
Piston #4: Pentron (some old spray can of solvent I've had for ~15 years)

Left 'em on for about an hour, then cleaned it off.
Simple Green did some good, but this piston was basically pretty clean already.
Brake cleaner just evaporated, as I expected, and did little good. I does work some when it is still there and you add elbow grease. It just doesn't hang around long enough to be a good penetrant.
Pentron didn't seem to do much; but this is a very old can too.
What worked best turned out to be the WD-40 Penetrant. So I am now soaking all four in this stuff, until this evening.

Just found some oven cleaner! Gonna try it out if the WD doesn't get it all. The pistons are fully functional; the buildup is super-thin, just cosmetic. Just thought it would be nice to have them super-clean like the combustion chambers.