I have a used head I am using to replace my head with the burnt valve (thanks Ski). The used head is currently disassembled and I would like to clean up the exhaust valves before reassembly. They have quite a build up of carbon - especially at the stem radius. Any ideas?

Thanks,

 

soak them in some cleaner, carb dip is not bad neither is motoroil, then brass brush the bigger chunks and when you get them pretty clean chuck them in your drill press or lathe and finish them off with some fine steel wool or scotchbrite try to stay away from the valve guide area as well as the valve seat. the porsche valves are pretty tough but i never take a chance on them not sealing. DO NOT media blast them with glass or sand, you will surely hate yourself in the morning. just make sure they are 100% clean before going back in.

 

a wire wheel works best in my experince, one of the bench mounted ones, or a wire brush on an air tool/dremel type thing

 

Mount the valve stem on a drill, set the drill on the lowest speed and use a wire brush (steel) for the hard deposits.

 

Mine were so caked up I chucked them up in a lathe and spin them using emory cloth
to sand off the carbon

 

I have always cleaned mine on a wire wheel on a bench grinder. If you are having the faces recut (which you should) then hitting them wont matter. As a previous poster stated, don't go up the valve stem to the part that runs in the guide .. leave that alone. You can also wire wheel the grooves for the collets.

 

seafoam?

 

Just don't go too crazy with the abrasive and put scratches in the metal, i.e. stress concentrations where a crack can start.

Carb cleaner takes most everything off but smells like $%*!.

Good luck!

 

I am pretty sure you can push a valve against a wire wheel for as long as you want, and it will never scratch. I have done this many times, never a problem.

 

^^ True

 

ditto- wire wheel on bench grinder. I've done it hundreds of times without any problem ever.
It's quick and easy.

 

Glass bead them if your going to reface them.

 

Wire wheel on a bench grinder did the trick. I would have thought it would scratch the surface but it didn't leave a mark.

Thanks guys.