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Discussion Starter #1
I'm cleaning the valves on a Y8 head I recently bought used. After searching this forum and others for some tips and experimenting on my own, I've found that soaking the valves in Seafoam does a decent job of removing or softening carbon buildup. However, there always seems to be 10% or so that won't rub off. For that, I used a brass Dremel wire wheel. On 1 valve I tried a steel wire wheel and it removed the carbon as well as what seems to be surface coating. How important is it to avoid doing this? I've seen some write-ups with photos of super shiney valves.
 

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if your head is still in the car and its running get a small mix of water and atf fluid and it will clean it, its an old trick. also if its out of the car i would just get a new setup
 

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At work, when rebuilding heads, we use a wire brush to remove carbon. The wire brush is spinning on a bench grinder and you just knock all the carbon off. Typically, stock honda valves bake that carbon on there very hard, so a bead blaster is very handy. I'll get some pictures of a finished set up here sooner or later. It's night and day!


I bet that if you took your valves down to a machine shop, it would cost less to have them clean, face(grind a new valve seat contact area), tip(grind a new stem tip contact area), and possibly bead blast the combustion chamber side (only if the carbon is giving them a really hard time). They would be as good as new, but the valve seat needs to be grinded as well, plus lapping would be even better! I would at least bring the valves and head (disassembled and cleaned is usually cheaper) to the shop and have them do the work. Tell them no reassembly and no cleaning, and it should be quick and cheap. Probably cheaper than if you bought just new valves! And, it would perform much better. You could lap them in when you get the stuff home. When lapping, mark the valve position (intake:1-8 and exhaust:1-8 ) and make sure it gets back to that spot. Good luck with the motor.
-josh-
 

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Discussion Starter #7
A set of new valves are $96 + shipping from Majestic Honda.

I've managed to remove the carbon from the combustion chamber and ports. I think the guides are ok and new valves will help compensate for some minimal wear there. I will lap in the valves and see if I can get a good seal based on a water test. If this doesn't work out, I'll have a machine shop re-cut the seats and try again.

The rest of the head is clean so the only other thing I'll have the shop do is re-surface it.
 

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About 2 years ago, I took my z6 head to the local v8 machine shop (coincidentally the same one I work at now...) and I brought it in assembled. I asked for a 3 angle seat and .020" mill. They cleaned/faced the valves as well, and cleaned it up to be assembled. They charged me 110.00 out the door for the work without reassembly. I think that's about what you paid for just the new valves + lapping compound.
 

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Discussion Starter #10
Well in my case, it's not necessarily about saving money or getting the work done by a professional. For me is a learning process and the satisfaction of doing it myself no matter what the results are.

Since this is a used head, I don't know it's history, and I don't think I have the means to accurately determine if they are out of spec (bent or worn), getting new valves alows me to be sure the valves have no defects. I've also noticed some pitting on the exhaust valves where the stem starts to widen where it forms the face.
 

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sql_civic said:
Well in my case, it's not necessarily about saving money or getting the work done by a professional. For me is a learning process and the satisfaction of doing it myself no matter what the results are.

Since this is a used head, I don't know it's history, and I don't think I have the means to accurately determine if they are out of spec (bent or worn), getting new valves alows me to be sure the valves have no defects. I've also noticed some pitting on the exhaust valves where the stem starts to widen where it forms the face.

used head? buy you some new valves and call it a day.
 

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Discussion Starter #13
I started this thread hoping to get a discussion on how to remove carbon from valves as opposed to what should I do with head I'm working on now. The idea is to remove carbon without damaging the coating.

After surfing around reading many DIYs and post on various forums including this thread. Here's a list of suggestions:

Low Impact

Brake fluid
Seafoam
ATF fluid and water
Techron
Acetone
Oven cleaner

High Impact

Wire brush on bench grinder
Dental pick
Dremel steel brush
Dremel brass brush
Scotch pad
Glass bead

or of course,

Buy new ones!

I'll try some more of these ideas, but so far seafoam has worked the best but not completely.
 
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