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Discussion Starter · #1 ·
Can anyone point me to an existing thread about how to properly clean my Exhaust Valves?

Subject car: 2005 9-5 Aero (160,000 miles)

While I'm doing the head gasket I decided to refresh the Timing Chain, Guides and Gears, and replace the Valve Stem Seals. I have decided to clean the valves up which is easy for the Intake Valves but I have questions about the Exhaust Valves.

Questions: (for reference see pictures)
  • Is there a coating on the exhaust valves that I need to worry about?
  • It seems that there is a lot of buildup on the valves (unless its coated). Is this normal?
  • If this is a coated valve it seems that some of the coating is chipping off. Is this an issue?
  • Is it recommended to just replace them? I'd rather not given the cost.
Thanks to everyone for any help you can provide.
Cheers - Aaron
  • Wood Audio equipment Ball Jewellery Circle
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I just used a brass wire wheel to remove that scale when I did the head on our '02 Aero. The brass is soft enough to keep from doing any damage to the steel valves.

You'll probably want to clean the head domes and maybe the tops of the pistons if they have a lot of deposits. Those can also be done with a brass wire wheel but you'll want to have a light touch when doing this. You don't need to apply pressure on the wheel; just let it lightly rest on the surface that you're cleaning and keep it moving around. Don't use those abrasive discs or pads as they are like sandpaper and can mess things up very quickly.

After you clean the valves and domes you should re-lap the valves to their seats in the head. That doesn't take too long to do by hand. Hopefully you know exactly where each valve came from so you can put them back the same way.

Finally, only use a flat scraper on the head gasket mating surfaces. Those have to be very flat and fairly polished.
 

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I agree 100%. I cleaned the exhaust valves the same way. It's pretty amazing what a brass wire wheel can do to clean those up. I also hand-lapped the valves afterwards and was careful to keep track of which one went where.

Edit: that's not a coating on the valves that's chipping off. That's just carbon buildup that's chipping off. If you go the wire wheel route, make sure to wear face protection. When chunks of that go flying, you don't want them smacking you in the face.
 

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Discussion Starter · #5 ·
Hi guys - Thanks for the advice and information.
The brass wheel sounds like a great idea. Unfortunately I didn't see the post soon enough and I only have one valve left to clean. I ended up using a RED Scotch Bright pad, WD40 and mounted the valve to a drill to turn it quickly (note: be carful to protect the valve stem). The results are fantastic but it takes about 20 - 30 minutes per valve. 😬
I have been tracking proper position of each valve and I'm planning to lapping the seats as well. I've already cleaned the pistons and I will be cleaning the domes. I'll post some before/after pictures once I finish up the work.
 

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I've used something much more gruesome for non-wearing parts to get the carbon off. Like a good Norweigen hardened HRC59 blade.... Good effort for doing it with Scotch bright pads. That's the last pass for me. Yes the seats need lapping if looking at that exhaust valve, but not much. Only the fine paste and by hand not drill. A few swipes either direction will do it.
 
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