Beryllium Copper Seats/Bronze Guides and Titanium Valves

[bob460]

Just get them CRN coated, the valve's will last longer!!

[fabr]

I think I pretty much said that in the first post.

[Alaskaracer]

I run Ti valves and beryllium seats on my stuff. Intakes are crn coated, exhaust are not....ZERO issues, and intakes have never had to be ground the last three freshens on the heads...actually, exhaust didn't either for that matter.....seats needed minor touch and done....

[fabr]

Thank you for that but if I recall correctly,your application is drag racing. My application is non competitive baja type off road running and needs to last at least 4-5 K miles between yearly refreshes. I cannot see uncoated (CrN) titanium valves doing that. Seems like apples to oranges to me.

[williamsmotowerx]

Ti dirtbike valves have to be coated. Dirt gets through filters and wears valves

[fabr]

Ti dirtbike valves have to be coated. Dirt gets through filters and wears valves

Ah,good point. I would be similar. I will definitely run CrN coated. It just does not make sense to me not to regardless of the application. FWIW,the guys trying to sell me a new set of heads and telling me I would be fine running uncoated Ti valves on iron seats lost a sale. Honestly,I feel they were being dishonest with me. I have little tolerance for that.

[Momus]

CrN 110% It is a superlative coating: very hard, very tenacious, not expensive, low friction and aesthetic.

My feeling is anyone selling uncoated, or moly coated valves have very old stock they are trying to quit.

[Alaskaracer]

I could be wrong, but I think the Corvette runs Ti valves......I know Ducati does as well.....If they last in those applications, they will in others

[fabr]

I could be wrong, but I think the Corvette runs Ti valves......I know Ducati does as well.....If they last in those applications, they will in others

Coated Ti intakes and sodium filled exhausts. Back to my original question. I don't think there is anyone that will doubt the much greater endurance of CrN coated valves. If anyone can point to even one example of any current OEM using uncoated Ti valves I'd like to see it.

I'll spill the beans on who it is that tried to BS me into buying their heads for an endurance application with uncoated Ti valves running on iron seats. It was http://mmcompetitionengines.com/ . I was led there by an article where Scott Shafiroff used them to supply the heads he used on his street SB2.2. https://www.enginelabs.com/engine-tech/ ... gen-i-sbc/ Yes ,he used steel valves for the project but I figured if Shafiroff trusted them ,so could I. All was going well until I said i wanted coated Ti valves .They said coated were not needed . I asked them how much more durable coated vs uncoated was. He said he had no idea but uncoated was fine and they did not keep coated in inventory but had uncoated on the shelf and they supply none with coated. FWIW,I agree with a previous poster that it appears they were just interested in clearing out old inventory regardless so long as I would fall for that BS. Well,they aren't going to make the sale to me. I just do not appreciate the feeling of smoke being blown up my ass for any reason.

[Alaskaracer]

That would piss me off too....

[David Redszus]

Years ago, we were asked to consult on an engine problem that a NASCAR team/builder was having with Ti valves
and CuBe seats.

They were evaluating unleaded race gas and the Ti valves would not last longer than 100 miles.

Cutting to the chase, the problem was micro welding of the valve to the seats when using unleaded
gas; problem disappeared when leaded race gas was used. NASCAR insisted on going green so a solution
had to be found.

The solution was to use coated Ti valves when using unleaded gas. After a great deal of experimentation,
the proper coating was found.

[fabr]

I have read of that being the issue with uncoated valves whether using copper or iron seats especially with 55-60 degree seat angles. If I'm not totally full of it,the coating settled on was/is CrN. I'm running true E85 and would think it is just as bad as unleaded so far as valve/seat erosion. Thanks to all for the replies!

[Momus]

I could be wrong, but I think the Corvette runs Ti valves......I know Ducati does as well.....If they last in those applications, they will in others

Coated Ti intakes and sodium filled exhausts. Back to my original question. I don't think there is anyone that will doubt the much greater endurance of CrN coated valves. If anyone can point to even one example of any current OEM using uncoated Ti valves I'd like to see it.

I'll spill the beans on who it is that tried to BS me into buying their heads for an endurance application with uncoated Ti valves running on iron seats. It was http://mmcompetitionengines.com/ . I was led there by an article where Scott Shafiroff used them to supply the heads he used on his street SB2.2. https://www.enginelabs.com/engine-tech/ ... gen-i-sbc/ Yes ,he used steel valves for the project but I figured if Shafiroff trusted them ,so could I. All was going well until I said i wanted coated Ti valves .They said coated were not needed . I asked them how much more durable coated vs uncoated was. He said he had no idea but uncoated was fine and they did not keep coated in inventory but had uncoated on the shelf and they supply none with coated. FWIW,I agree with a previous poster that it appears they were just interested in clearing out old inventory regardless so long as I would fall for that BS. Well,they aren't going to make the sale to me. I just do not appreciate the feeling of smoke being blown up my ass for any reason.

Some of the Japanese bike makers are supplying the Ti valves in their high performance road and possibly MX engines with what appears to be a moly coating. I recently bought some Suzuki valves for a ancient Honda single project and they were matte grey in colour, seemingly moly.
None that I've seen are using uncoated, that's for sure. The Honda Ti valve equipped MXer engines are using iron guides. This may be because typically a motocross bike has a low WOT duty cycle but it indicates that Ti valve tech is maturing and the metallurgical caution of relatively early adopters and now effective coatings make their use hum ho these days.

[fabr]

I'm thinking but have no info that it would be a DLC coat if black or dark gray.

[Momus]

I'm thinking but have no info that it would be a DLC coat if black or dark gray.

Not DLC.
I have plenty of DLC parts to compare.