Author Topic: How to get carbon build-up off of valves ???  (Read 17397 times)

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Offline carl

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How to get carbon build-up off of valves ???
« on: October 11, 2007, 02:45:21 PM »
Got any cleaning tips/suggestions ?

tia!,
-Carl



Offline OldSchool_IsCool

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Re: How to get carbon build-up off of valves ???
« Reply #1 on: October 11, 2007, 02:49:14 PM »
I haven't tried it myself, but I hear that straight water will bust it loose.  Seafoam also claims to do a nice job of it when it is injected straight into the cylinders.
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Offline BobbyR

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Re: How to get carbon build-up off of valves ???
« Reply #2 on: October 11, 2007, 02:54:25 PM »
Water works very well. Just spray it into the carb throat or if you have ports for carb synch just spay it in. It takes a bit of water so one spray and you are not done. Spray, let the motor recover, and spray again.
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Offline carl

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Re: How to get carbon build-up off of valves ???
« Reply #3 on: October 11, 2007, 03:01:32 PM »
Hmmm - water? I've actually got the head and valves off - trying to get them clean to check how they are sealing.

-Carl




Offline ProTeal55

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Re: How to get carbon build-up off of valves ???
« Reply #4 on: October 11, 2007, 03:07:00 PM »
I always heard the best way to get carbon off valves is to get some racegas int he tank and do some "aggressive" riding  ;D
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Offline 750essess

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Re: How to get carbon build-up off of valves ???
« Reply #5 on: October 11, 2007, 03:23:25 PM »
I use  walnut shells in my sandblaster cabinet, but have in the past scrapped it off, used oven cleaner, scotchbrite pad, etc.
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Offline BobbyR

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Re: How to get carbon build-up off of valves ???
« Reply #6 on: October 11, 2007, 03:31:03 PM »
Hmmm - water? I've actually got the head and valves off - trying to get them clean to check how they are sealing.

-Carl


Well Carl you can boil them in a pot. They get much hotter in the engine than they will in the pot. You can torch off carbon also, but a touch of the torch and then a wire brush and repeat until they are clean..
But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?



Offline Bob Wessner

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Re: How to get carbon build-up off of valves ???
« Reply #7 on: October 11, 2007, 03:40:20 PM »
Hmmm - water? I've actually got the head and valves off - trying to get them clean to check how they are sealing.

-Carl



Since you have the head off and valves removed, I have read that spray oven cleaner will remove the carbon. It certainly works on carbon resulting from splatters in an oven. Might be worth a try. I've never done it though. Might take several applications depending on how thick the carbon is. Wear gloves and be sure to clean and dry the parts thoroughly afterward.
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Offline Short Round

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Re: How to get carbon build-up off of valves ???
« Reply #8 on: October 11, 2007, 03:53:50 PM »
I have my top end off right now as well and am in the same situation.  I have yet to take the valves out but that is going to be done in a week.  I found that the intake valves come clean with ease but the exhaust valves are the ones that are a pain.  I havent used oven cleaner yet but I think I'm going to give it a try tonight to see if it will loosen it up a bit.
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Offline hcritz

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Re: How to get carbon build-up off of valves ???
« Reply #9 on: October 11, 2007, 03:56:34 PM »
Hey Guys...
Wire brush on a bench grinder will make quick work out of cleaning up really nasty exhaust valves!



Offline carl

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Re: How to get carbon build-up off of valves ???
« Reply #10 on: October 11, 2007, 04:25:11 PM »
The wire brush idea kinda scares me. I don't wanna reshape the metal (aluminum) in any way. It'd be nice if there was something that just broke down the carbon into a liquid that could just be wiped away.

I will try oven cleaner and some scotchbrite (great idea!) pads, and let you guys know my results.

thanks!,
-Carl



Offline hcritz

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Re: How to get carbon build-up off of valves ???
« Reply #11 on: October 11, 2007, 04:30:56 PM »
Carl. are you cleaning the head or the valves????
The valves are made of an extremely hard steel...the head is of course alum.
No way you will hurt the valves with a wire brush.
Several ways to clean the actual head...Loctite makes a gasket remover that seems to remove carbon pretty well, but it will also remove the paint from the head if that's an issue for you.



Offline carl

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Re: How to get carbon build-up off of valves ???
« Reply #12 on: October 11, 2007, 06:07:18 PM »
I am cleaning both the actual valves and the head. Totally appreciate everyone's help - I tried the oven cleaner, and it worked very well.

Woo hoo! Maybe I'll get to ride before it starts snowing... :)

thanks all,
-Carl



Offline rhinoracer

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Re: How to get carbon build-up off of valves ???
« Reply #13 on: October 12, 2007, 01:29:12 AM »
I believe you're talking about hard carbon deposits vs black soot. I had to put my valves in a drill press at high rpm and polish them with emery cloth.

Nothing else would cut thru the hardened carbon coating. Not gasoline, not diesel, not wire brushes. I didn't try a wire wheel on a hand drill with the valve on the drill press, I guess it would have worked like the emery cloth.
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Offline Terry in Australia

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Re: How to get carbon build-up off of valves ???
« Reply #14 on: October 12, 2007, 07:28:52 AM »
The "wire wheel on a bench grinder" is the best method I've used, for sure.

A quick word about "de-coking" the combustion chamber and valves with water though, just to emphasis that the water should be sprayed in a fine mist from something like a little plastic spray bottle directly into the carb bell-mouth or as Bobby said, trickled thru the vacuum take off while the engine is running.

Don't over-do it though, water doesn't compress so if you just use your garden hose to spray it into your carbs, you might just end up with some bent rods! Cheers, Terry. ;D
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Offline Helo229

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Re: How to get carbon build-up off of valves ???
« Reply #15 on: October 12, 2007, 07:34:42 AM »
Just a thought, but if you have the valves off, try sticking them in a freezer. Like someone said on here before, you could boil them, but it gets much hotter inside the engine, so the carbon is likely to stick on through metal expansion. If you get them frozen it might compress the metal enough that some carbon may break off.

I've never tried this and don't know if it would work or not, but in theory it seems sound.



Offline rbmgf7

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Re: How to get carbon build-up off of valves ???
« Reply #16 on: October 12, 2007, 07:39:24 AM »
i used a wire brush but on a dremel. it's a lot softer than a bench grinder grade wire brass wheel. polishes them up really nice. you can also use them inside the chamber to remove deposits on the head. but do try to avoid the valve seat.



Online greenjeans

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Re: How to get carbon build-up off of valves ???
« Reply #17 on: October 12, 2007, 11:12:24 AM »
 ???So.....to clean them off while everything is still together - you just mist some water with a spray bottle into the carbs?  While the engine is running ?  Wait a bit (if that doesn't stall it out)  and repeat until they are clean .....????   That seems too easy, I think I give it a try when I get my projects running again.
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Offline goon 1492

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Re: How to get carbon build-up off of valves ???
« Reply #18 on: October 12, 2007, 11:24:27 AM »
just a warning about using water in the head while its running, if you do this do it when the motor is cold or you run the risk of cracking the head, when we did this trick in automotive votec 10 years ago in highschool the teacher said always do it with the engine cold or the massive cooling of the head when the water is introduced can crack the head, im sure its a similar concept with thes heads, and also we used 1 part brake fluid and 3 parts water and ran the throttle about 3/4 full or the water would bog it down too much. Hope this helps and if you try it do a search on the net first and learn as much as you can before its too late to turn back. 8) :P
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Re: How to get carbon build-up off of valves ???
« Reply #19 on: October 12, 2007, 11:27:21 AM »
Helo229

The valve operates at temps from say70deg to 1400? deg.

freezing it to 20 deg from 70 may not make a big difference.

I like the ideaof spinning in drill pres or lathe, but to err on side of caution I would use a thin shim like beer can, to prevent marring stem.. if you do, your guide is gonna hate you!

Also use fine emery and dont get too aggressive, before you know it you could loose 1/2 thou..
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Offline BobbyR

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Re: How to get carbon build-up off of valves ???
« Reply #20 on: October 12, 2007, 12:38:18 PM »
???So.....to clean them off while everything is still together - you just mist some water with a spray bottle into the carbs?  While the engine is running ?  Wait a bit (if that doesn't stall it out)  and repeat until they are clean .....????   That seems too easy, I think I give it a try when I get my projects running again.
Yes it is that easy. You can mix some alchohol into the water. Since you are doing one cylinder at a time the motor should not stall. That cylinder will miss badly which means you are getting enough water in there. The water turns to steam and blows the carbon off. 
 
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Offline morini

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Re: How to get carbon build-up off of valves ???
« Reply #21 on: October 16, 2007, 06:05:37 AM »
Glass jar, a dessert spoon of caustic soda, warm water, let valves soak for a few days.  Crud will brush off...

 

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