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Thread: Removing carbon deposits?
11-10-2007, 10:34 PM #1
I have a cylinder head apart right now, and am wondering what the best way to remove carbon deposits from the valves and cylinder head, particularly the exhaust ports.
The head is an aluminum head, and standard (not SS) valves. I have tried a wire wheel on the exhaust valves, but the deposits are pretty hard and heavy.
Any good chemical solution? If I drop the head off at an automotive machine shop to have it hot tanked, will that remove the carbon or is that a seperate procedure?
11-10-2007, 11:57 PM #2
Old fashion carburetor cleaner you get from an auto parts place works pretty well. I have no idea what the horrible stuff is but it works. You can also take it to an auto parts place that does machine work such as boring cylinders and grinding/milling heads and ask them to "vat" the head. Their "vat" has who knows what hazardous waste in it that takes off the carbon etc. Last time I had that done the charge was small but that was before EPA mindset got out of control.
11-11-2007, 12:03 AM #3
take a piece of 1/2" copper tubing and flatten one end of it and use for scraper, the cooper is softer than the aluminum and should not damage it, lots of elbow grease required.
11-11-2007, 12:05 AM #4
Try oven cleaner. That is the name it is marketed under over here. It is a spray can with a foamy white stuff used to clean kitchen ovens.
11-11-2007, 02:50 AM #5
Thanks for the replies.
I have thought about the oven cleaner, at least on the valves, but the active ingredient is sodium hydroxide (lye) and that is VERY bad for aluminum. It might be OK if I do not leave it on for very long, but I'm not taking that chance. There is also the question of how it will react with the bronze guides.
The upswing is, I was going to have an engine shop do the actual head casting, I am mostly concerned with the valves. I have them all organized to which hole they came out of, and I am afraid if I bring them to a shop, they might mix them up on me. So I might be able to use the oven cleaner yet.
Thanks again, and still open to suggestions!
11-11-2007, 03:12 AM #6
Let the parts soak in full strength Simple Green cleaner. You'll probably have to soak them overnight, then rinse off with water and a stiff bristled brush. Try it, you'll be amazed! I never thought much of Simple Green, but I read somewhere it would take carbon off of pistons, so I tried it. Worked very well, the pistons cleaned up like new!
11-11-2007, 03:49 AM #7
As you already have the valves out of the head just throw them in the lathe & clean them up. I've used my drill press before with good results...Start with metal to knock the big lumps off & work your way to red scotchbrite for a final polish.
Simple Green will also work, it really does a number on carbon... good way to kill an alterator is to use SG to clean down the engine bay of your vehicle. Althernators don't work too well when you dissolve the carbon brushes.
11-11-2007, 06:32 AM #8
I second the carburator cleaner from the auto parts store. Comes in gallon and (I think) 5 gallon pails, with a little basket inside. In my experience It doesn't seem to do anything bad to aluminum, red metals, or steel, as the label claims. I left a carburator in it for a week by accident, and when I got it out, it was still fine, and VERY clean. you wash the stuff off with water in your shop sink, after letting the chemicals drain off back into the tank. then blow off the water with air or wipe dry. can be reused a bunch until too much junk settles to the bottom.
The gallon is a nice size for valves, carbs and the like. larger would probably be better for anything bigger than a motorcycle carb. you can do them one at a time overnight if you want to keep them organized, or wrap in window screen and tag them. I suppose you could wrap them all in individual window-screen pouches and tag them and send them off to the pro's too.
I wonder if glycol based brake fluid is probably the same stuff as the carb cleaner, or if not if it would also work well. takes off paint well enough, can't see why it shouldn't strip carbon off as well.
hope this helps,
11-11-2007, 06:45 AM #9
It is years since I have had any head work done, but I am pretty sure they bead blast the combustion chambers and ports. Gets all those hard-to-reach parts of the ports without doing any damage, looks like new.
I guess you could engrave the valves (air grinder) to identify, but IMHO a decent head job would normally include refacing valves and seats, so numbering not so important.
11-11-2007, 06:58 AM #10
----Try oven cleaner. That is the name it is marketed under over here. It is a spray can with a foamy white stuff used to clean kitchen ovens.----
DO NOT use this stuff or you WILL NOT have a decent article when that lot is thru with it, it WILL eat into the ally where ever it touches the ally.
These spray cans of oven cleaner have Caustic Soda in the make up of the ingredients, which is used in part of the process of making aluminium.
No need to ask how I know about this, just say voice of experience talking here.
11-11-2007, 08:15 AM #11
Go to a chevy dealer and get some GM top end engine cleaner. There are two formulations, the older one in the steel can works better. This product was designed to eat carbon.
A lot of folks swear by this stuff for cleaning the carbon out of firearms.
11-11-2007, 08:26 AM #12
Use paint stripper. It is methyl chloride. The same chemical as carburetor dip cleaner. It is safe for aluminum. It is sometimes called aircraft stripper, being it is safe for aluminum. It will clean the carbon on your head easily as it strips paint.
Wear gloves, and keep it out of you eye.
11-11-2007, 08:34 AM #13
Oven cleaner will ruin aluminum. Don't use it!
11-11-2007, 08:45 AM #14
for the valves ...wire wheel on a bench grinder .
following is old post of mine copied to here
The combustion chambers and the ports were cleaned with paint stripper and toothbrush....here you see the old carbon just dissolving on contact with the paint stripper and oozing out. .
Make sure you wear goggles..
Caution only use methanol type paint stripper, should say on the label methanol or methylene-dichloride
other paint strippers contain caustic ...that corrodes and turns alloy black
After a rinse it will look like this.
I also cleaned the cavity ,above, around.inside head were lots of dirty oil residue accumulates..
This I did with paint stripper,toothbrush,paint brush ...and pressure washer.
all the best.markj
11-11-2007, 12:18 PM #15
Ever do this experiment:
Take off a head, clean all the carbon deposits
off of it. Put it back on the engine, and
run for an hour. Take it off again and look
at it. Guess what you find...?
m stoner liked this post
11-11-2007, 12:35 PM #16
this works good to antifreeze in a pot then heat on low for small parts a crock pot works great pistons in the pot come out like new jim
11-11-2007, 12:49 PM #17Caution only use methanol type paint stripper, should say on the label methanol or methylene-dichloride
other paint strippers contain caustic ...that corrodes and turns alloy black
Also had to drain the stuff out of the aluminum tank & carb on my old JAP 500 speedway bike for the same reason....
& it's not too good for lawns... (don't ask)
11-11-2007, 04:12 PM #18
I had not observed that Methanol affects aluminum directly, but it is hygroscopic (attracts water) and that causes the aluminum to corrode. Most people running aluminum blocks and heads in race vehicles add a bit of soluble oil to the water to stop this problem. Your street driven vehicle should be protected by the coolant they use these days, although it will wear out eventually.
You can have the heads hot washed at any place that has one (hot water and soap only) and then bead blasted as another member posted. If you do have bead blasting done, it is critical to get all the glass bead material removed from the head. Normally first high pressure air, then soapy water from a pressure nozzle and then the same with clean water and blow dry. Those little glass beads are bad news in an engine.
11-11-2007, 05:28 PM #19
methylene chloride stripper does work great, but your body metabolizes it into carbon monixide, so beware. use ina **WELL VENTILATED SPACE!**
11-11-2007, 05:36 PM #20
Unless you plan to do more work to the heads than removing the carbon deposits (port and polish) you are just going to make extra and unnecessary work for yourself. Carbon really likes to hang out in all the little imperfections caused by mass production casting, Jim Rozenís experiment will show this, but that sounds like a lot of extra work too. However, excessive carbon buildup can raise your compression ratio and make bad things start to happen inside your combustion chamber. To answer your question, the spongy abrasive material that is available for dremels and grinding tools works very well. If you are going to remove some aluminum from inside the ports be careful!!!! Grinding stones and carbide bits will eat up aluminum heads pretty quick. Most people will tell you that if you donít know what you are doing donít mess with them. Those people are probably afraid of you being faster than them. Smoothing out the casting imperfections wonít hurt them any. Donít get carried away and remove as little at a time as you can possibly stand. Here's a pic of a set of Harley heads that I am working on.