Carbon Removal From Pistons

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What's the best/easiest/safest way to remove carbon deposits from aluminum pistons that have been removed from the engine? Ideally looking for a chemical to soften the carbon if not dissolve it completely.

These are expensive pistons, I won't be scraping them with a hacksaw blade or any of the old techniques, and if I can chemically soften the deposits in the ring lands enough that I can get it out with a Scotchbrite pad or something similar so much the better.
 
Soak them in Berryman's Chem-Dip......Then Mineral Sprits & Red Scotch-Brite pad for final clean-up.

The easiest is to put them in a Hot Water Spray Cabinet with a Aluminum safe detergent....The ones made for cleaning Transmission cases, But not everyone has access to one.
 
Just lacquer thinner. Cheap as hell and works great. Pretty certain its safe with brass, too.

Works so well I wouldn't for a second think about spending more money on something else.
 
A pan/container filled with this so it covers the whole piston will give great results if left for a couple of days.
A stiff nylon brush and water rinse will clean all the junk away. It is harmless to aluminum, brass, rubber, plastic, etc.

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When the engine is back together, consider this. Years ago here on BITOG a member posted photos of pistons after he had regularly run Marvel Mystery Oil in his gasoline for many, many miles. The pistons were clean—no carbon. None. But there are so many threads mentioning MMO that I can't find the exact one. And if your application isn't automotive but, say, aviation, using MMO might not be a good idea.
 
I understand that scotchbrite shoud never be used on an engine EVER. The theory goes that you thing all the abrasive has been removed, but somehow it remains hidden in tight spaces. Once the engine is reassembled, those particals get distibuted to the rest of the engine causing bearing wear and other damage.
 
ekrampitzjr said:
When the engine is back together, consider this. Years ago here on BITOG a member posted photos of pistons after he had regularly run Marvel Mystery Oil in his gasoline for many, many miles. The pistons were clean—no carbon. None. But there are so many threads mentioning MMO that I can't find the exact one. And if your application isn't automotive but, say, aviation, using MMO might not be a good idea.
Click to expand...
I think MMO may have cost me an engine when the carbon came loose, I totally believe it works as advertised and I would not use it again.
 
I've read the same thing about Scotchbrite. I have no observations to back it up but I do have an engine that I rebuilt in 2014 that I glass bead blasted the pistons and then cleaned them up with Scotchbrite pads, that engine is still plenty strong and doesn't smoke, burn oil, or make any bad noises. These were very expensive forged aluminum pistons, they are the ones that got scarred up by the MMO and carbon referenced above.

I think sometimes stuff gets put on the internet and repeated enough that it becomes our common sense, it sounds plausible, and it may be true under some circumstances in some restricted sense, but it still doesn't necessarily work that way.

This particular engine I just washed everything real good in hot soapy water and changed the oil at 50 and 500 miles, it seems to still be doing fine.

The pistons in question in the OP here won't get the same treatment, these are Keith Black pistons that are nearly new, they are just carboned up hard from a bad head gasket. I will do a little experimentation with the recommendations here.

Thanks all!
 
NitroM3 said:
This is a no brainer, you take them to a engine machine shop and have them hot tanked and cleaned. Plain and simple. About 50 bucks for a set of 8!
Click to expand...
DIY are not likely to be able to clean up all the areas on a piston that is carboned up like in the ring lands (without damaging them) and gas ports (if you have them) wrist pin and under the piston crown area's .
 
Not really applicable to the OP since his pistons are out of the engine,,,,,, but if one has a running engine with some carbon build up there is very easy way to remove carbon deposits as the engine runs.

Water injection. It’s that simple. Don’t overdo it as you can get into hydro-lock territory.

just take a spray bottle and with the air cleaner off give it a couple of pumps . Repeat every 15 seconds for a couple of minutes. If the engine dies you’re using too much. After the engine cools take out a spark plug and inspect the piston tops.

Anyone who’s had a head gasket leak coolant into the combustion chamber can attest how well this technique works. The cylinder with the coolant leak will have a perfectly clean piston top. The others will be carbonized. It’s steam cleaning at its simplest.


Z
 
Listen to what Clienbarger says to do. If the pistons are still in the block red scotchbrite with berrymans. I've used chlorinated brake cleaner and red scotchbite also but it requires a lot of elbow grease.
 
Gimpy1 said:
Listen to what Clienbarger says to do. If the pistons are still in the block red scotchbrite with berrymans. I've used chlorinated brake cleaner and red scotchbite also but it requires a lot of elbow grease.
Click to expand...
Just remember if you get contamination behind ring and ring groove you can break a ring!!
This is by far the most common mistake DIY do and then wonder later what happened to their engine!
 
zray1 said:
Not really applicable to the OP since his pistons are out of the engine,,,,,, but if one has a running engine with some carbon build up there is very easy way to remove carbon deposits as the engine runs.

Water injection. It’s that simple. Don’t overdo it as you can get into hydro-lock territory.

just take a spray bottle and with the air cleaner off give it a couple of pumps . Repeat every 15 seconds for a couple of minutes. If the engine dies you’re using too much. After the engine cools take out a spark plug and inspect the piston tops.

Anyone who’s had a head gasket leak coolant into the combustion chamber can attest how well this technique works. The cylinder with the coolant leak will have a perfectly clean piston top. The others will be carbonized. It’s steam cleaning at its simplest.


Z
Click to expand...
nice!^^^^^^(y) :cool: (y)^^^^^

All my vehicles run some form of water injection or water/meth and recently I even built a sorta water vaporizer. Go look at my thread.

I have also been building custom water injection and have sold and used almost everyone water injection ever available on the retail market. I still have Marvin Miller water injection parts dating back in the mid 70's. LOL

NitroM3 Mazda 3 2018 2.5 Automatic

Purchased new at the end of 2018 Mazda3 Touring and immediately started modding.
bobistheoilguy.com
 
NitroM3 said:
Just remember if you get contamination behind ring and ring groove you can break a ring!!
This is by far the most common mistake DIY do and then wonder later what happened to their engine!
Click to expand...
Never had that happen. I did it with the pistons in the block with the heads removed during a head swap. If you're tearing down the engine completely, then hot tank the reciprocating assembly and rebalance it. You should remove the rings anyway, to get the piston groves clean. Just get everything hot tanked at that point.
 
JohnnyG said:
I understand that scotchbrite shoud never be used on an engine EVER. The theory goes that you thing all the abrasive has been removed, but somehow it remains hidden in tight spaces. Once the engine is reassembled, those particals get distibuted to the rest of the engine causing bearing wear and other damage.
Click to expand...

You never use a Scotchbrite abrasive "whiz wheels" on a engine. Using Red & Green Scotchbrite PADS with Solvent/Mineral Spirits to polish surfaces in perfectly acceptable, Though I do rinse the parts with solvent, Then blow them clean with Virgin Solvent, Then blow them dry with compressed air. As you're blowing pieces dry.....You'll see any residual debris as darker streaks meaning you got to clean it again.

Building Engines & Transmissions is labor intensive....A good chunk of it is cleaning & keeping things clean, Which is why I invested in a Hot Water Spray Cabinet.
 
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