Don Terrill’s Speed-Talk

Buying some new valves for my 292 heads I'm starting to work on and was thinking about buying some of the Nitrided Black valves. They claim more smooth finish on the stem and better corrosion for exotic fuels. I run alky, never a problem with chrome stems and bare stainless. Has anyone used these with decent results? Want some actual feedback, just didn't want to fall for a marketing ploy and get something worse than what a normal race valve would be and pay more for it.

haven't used them on any race car stuff but have used and seen them in some import and quad cycles heads with hard time on them and have not seen any abnormal wear on the stems... Honda does not recommend to grind the nitride off the valves faces but I have seen the valves with and without nitride on the valve faces..

I have seen a lot of stuff on import forums and the OE. Not much else though. The valves I was looking at looks like to me they have the faces without nitride. I don't know why it would hurt to remove it on a stainless race valve. Every other stainless valve doesn't have nitride on the faces. I understand nitride is a surface treatment, similar to hard anodize. I've seen it mostly in the firearms world. Great stuff for in barrels, helps the life of the barrel and corrosion resistance. If its good enough for uncle sam to replace chrome lined barrels with nitride steel, there has to be something to it. I'm sure it was well tested in that application.

It's a bit harder than chrome, but probably thinner. Transfers heat better than chrome.
Chrome can be sprayed on a bit 'grainy" looking, intentionally porous which holds lube, but the nitrided does not have that advantage. So.....pros and cons.
I was hesitant to use nitrided valves with bronze guides, simply because it isn't often done. Works ok the few times I've seen it tried, but I don't think it's AS good a combination as nitrided on iron, and chrome on bronze
In hard iron guides they last a LONG time, that's for sure.

It was going to be used with liners. The guides in my heads are worn, I'm replacing the valves anyway because of service life. I was thinking the smoother surface wouldn't work on the bronze liners as much. Didn't think about the rougher surface holding oil, would the oil get past the valve seal?

I use "black diamond' ,made by Kibblewhite ( Precision Machine)valves on my Triumph ...Mostly because they are the best quality for my application....I do know the black coating wears off if a valve sticks in the guide... The valve seating surface is not black

Trying something new when there is no issue in having to make for such a search can lead to problems you may not expect!

Chrome has been used on valve stems for how many years now with no down side?

If your making enough power / heat to need the aid of a black colored valve stem to save you then your barking up the wrong tree!

If speed talk would have been around 60 or 70 years ago, someone would have been on here asking about one of those new fangled roller camshafts. If truly not many people have had experience with them, I will probably stay stainless with chrome, they have been out for quite a while now, I would have thought there would be more feedback is all.

I use the nitride coated valves with bronze guides on Harley motors. Have been for years. Never a problem. Use them in cast iron guides as well.