Are valves surface hardened?

[G.W]

A buddy of mine is working on building up the 79cc predator engine I gave him for a little more performance. He wants to lap the valves and possibly send the head in to get a multi angle valve job done. He's concerned that the valves exterior are either coated or case hardened and doesn't want to lose their longevity by doing this. So does anyone know if just the exterior of the valve is hardened or coated? Thanks!

 

[Master Hack]

I found this:

Inlet Engine Valves are made from Chrome Silicon Alloy Steel and Exhaust Engine Valves are made from Chrome Nickel Silicon Alloy Steel (to operate under high temperature and high stress conditions).

So they should be the same all the way through.
When parts are made in china all bets are off. Could be Yak hoof alloy.

Do yaks have hooves? or are they like camel toes?

Never mind...

 

[G.W]

I found this:

Inlet Engine Valves are made from Chrome Silicon Alloy Steel and Exhaust Engine Valves are made from Chrome Nickel Silicon Alloy Steel (to operate under high temperature and high stress conditions).

So they should be the same all the way through.
When parts are made in china all bets are off. Could be Yak hoof alloy.

Do yaks have hooves? or are they like camel toes?

Never mind...

Makes sense. Thanks.

 

[Denny]

Heat treating a part that gets red hot is kind of a waste. No they are not hardened.

 

[Whitetrashrocker]

We cut new surfaces on car, race car, and airplane valves all the time.

 

[Master Hack]

I fail to see how a fancy valve job is going to help with performance gains. Unless the valve surface is burned to begin with.

 

[Denny]

Fancy valve jobs as you call them improve airflow through the valve and seat area and increase the airflow. It’s as important or maybe even more important than porting. But they compliment each other also. The old standard used to be 3 angle valve job now a days it’s not uncommon to see 5 and 7 angle valve jobs. It’s all about the flow man! Ask momma about flow she can tell you how important it is.

 

[Master Hack]

Yeah, l get all that, though ya over sold it some.
that alone, with 79cc to work with isn't really worth the effort.
my $0.02 thats all.

 

[Denny]

I totally agree with you about that!

 

[panchothedog]

There are a whole heck of a lot more things that could be done to that engine that would do more than any amount of angle grinding on the valves.

 

[G.W]

Although a multi angle valve job isn't the most important thing, he is doing it because he already has the head off to shave it for higher compression and smooth out the port castings.

 

[panchothedog]

That's good to hear. That makes a lot more sense. Tangible gains.