Cleaning Carbon off piston tops during HG change

[BOP4ever]

Is this worth doing and if so what is the best safest way to do it..

 

[charlief1]

Unless you've got extensive carbon build up it's not really worth it.

 

[BOP4ever]

I'd considerate light just a thin hard coating that laughs at carb cleaner.

 

[charlief1]

Don't worry about it. Once you get the engine back together add a slight amount of water to the alky for a short run and it'll go away, if you're running alky that is.

 

[BIGPSI]

diesel fuel and a scotchbrite. i had a 41k motor that had been laying around and i cleaned it up and put it in with ported heads. not sure if it matters,but looked nice and clean when i assembeled it

 

[turbo nasty]

No way use scotchbrite!! That abrasive lint will get all in the ring lands, between the rings, etc and eat the bores and pistons.......Asemble the engine...and do a top end clean with the engine running...with Seafoam.....typically plugs are changed after this as well as oil

 

[BIGPSI]

so you think a red scotch brite which is 600grit will eat cyl bore and pistons? dude you are nuts!

 

[chopped39]

Leave it. Dont use any kind of abrasive pads or anything else while heads are off. That stuff is nowhere around when I assemble an engine. What happens if it gets past the rings? Plastic razor blades to clean deck and head surface. Alcohol to clean surface. I love when I see guys cleaning surfaces with roloc discs plastic or not They should not be used. We used to get heads that someone cleaned with a plastic disc. I would take 2 thou off and you cold see the low spots. Leave the carbon and add water to alky kit as stated above. good luck

 

[deezdad]

Pretty sure a tech bulletin was put out by GM back in the day warning against this, the resulting metal wrecking the motor. It was shown to me by R.C. after he saw 1st hand what GM goodwrench did to my motor back in 2005

 

[BIGPSI]

well i did it by hand with red pad and and no roloc ,had each piston at the top then cleaned with brake clean and compressed air been driving it for 2yrs after and no problems, oh well

 

[turbo nasty]

so you think a red scotch brite which is 600grit will eat cyl bore and pistons? dude you are nuts!

Well slick you spouted off with scotchbrite and you are wrong.....You gave bad advice...now you have a sandy vag due to being called out on it.

Bottom line, your saying to use a abrasive in an area that it shouldnt be.

Common practice in industry not to use it on a assembled engine........It will also contaminate your bearings as well.

If nuts is doing it the right way then ...yep im nuts.

Have a nice day

 

[gnloyalty8777]

Well slick you spouted off with scotchbrite and you are wrong.....You gave bad advice...now you have a sandy vag due to being called out on it.

Bottom line, your saying to use a abrasive in an area that it shouldnt be.

Common practice in industry not to use it on a aseembled engine........It will also contaminate your bearings as well.

If nuts is doing it the right way then ...yep im nuts.

Have a nice day

I would NEVER use scotchbrite to clean the carbon off pistons. Thats crazy!!! I have a friend who has built mine and many other 109's as well as stage motors and if i told him i was going to do that he'd have a BIG problem.

 

[garyk1970]

Jason is right...never use adbrasives on internal engine parts....like scotchbrite, etc...

 

[turbo nasty]

 

[deezdad]

Pretty sure a tech bulletin was put out by GM back in the day warning against this, the resulting metal wrecking the motor. It was shown to me by R.C. after he saw 1st hand what GM goodwrench did to my motor back in 2005

GM tsb 87 61 24 is the bulletin number if ya wanna Google it

 

[BIGPSI]

well i am truly sorry for the bad advice! i didn't think it was hurting it since all i cleaned was the top of piston while it was at tdc. i didn't touch cyl ,bearings etc and it was a small 1x1" piece that was used already all was cleaned and blowed off one again Sorry!

 

[Jerryl]

On my setup, I have not seen the piston crowns “clean” after spraying a lot of alky for a long time. Maybe my definition of clean is different, but there were significant carbon deposits on the piston crowns. I was fighting KR at the time and decided to clean the piston crowns.

As far as methanol cleaning abilities; I soaked the head bolts in VP methanol and was surprised it did not really clean the oil as well as I expected. Not sure what I did wrong there as the results should have been different.
I realize there is a great temp/pressure difference in the intake and combustion chamber, but refer to the first paragraph.

Turbofabricator had told me to NEVER use Scotchbrite, and that was good enough for me . . . Since I like to start with clean parts, I used a “SOFT brass wire wheel” on the top of the pistons. With a very light touch it did a great job cleaning the carbon to my satisfaction.

"In Service" cleaning; I also conducted a test on an old piston with GM Top Engine cleaner to see what it would do later on. Here are my results. If it is sprayed it on a cold piston, it does not appear to remove much (If any) carbon. I heated the piston with a hand torch and re-sprayed it, and there was a significant difference I the carbon deposits. Matter of fact, the difference was so great, that I just had to repeat the experiment on another piston. It ended up with similar results.

I conducted the same test on the piston with methanol and even "burned the soaked piston" but did not notice any difference in carbon deposits.
I know there is a great temp/pressure difference in the chamber, but refer to the first paragraph.

I realize this is a long post . . . Just wanted to share my experiences.

 

[garyk1970]

well i am truly sorry for the bad advice! i didn't think it was hurting it since all i cleaned was the top of piston while it was at tdc. i didn't touch cyl ,bearings etc and it was a small 1x1" piece that was used already all was cleaned and blowed off one again Sorry!

No problem....we are here to help each other.I personally ruined A new engine...did a search here and found out why .....scotbrite circulates in the oiling system and ruined my bearnings.

 

[turbo nasty]

well i am truly sorry for the bad advice! i didn't think it was hurting it since all i cleaned was the top of piston while it was at tdc. i didn't touch cyl ,bearings etc and it was a small 1x1" piece that was used already all was cleaned and blowed off one again Sorry!

No sweat

 

[DR BOOST]

sanding or scuffing with a scotchbright will leave a finish on the piston that promotes carbon builup. Just leave it alone.