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I have titanium intake valves. When you make a hot rodded race motor everything is give and take. The bad things about titanium valves are: #1 You have to run special larger valve seat inserts. Normal valve seats will get beaten right out of the heads with high racing spring pressures. #2 Very hard to machine. That's why most every race team using them just throw them away during every head rebuild. #3 Type of guides and stem clearances are not the same as with SS. #4 The cost of $70 or so apiece really offset replacing $250 quality sets of springs.
The only real plus is because the valve is 1/2 the weight. lighter springs can be used - less spring heat - less spring fatigue......... Within one year my sollid roller springs had lost up to 25#'s of spring pressure anyway. I just throw them away and bought new K-Motions
So in simple terms NO they don't last as long and neither do titanium collars (retainers) They just aren't as strong. I threw away a set of them and went back to Chromemoly for my 1.56 springs
I have run sodium filled exhaust and titanium intakes on 8000+ rpm engines where they definately benefit. I really couldn't recommend usuage for under 8000 rpm.
My experience has also showed valve face cracking under extreme conditions ; when stainless would have survived.
i have a set and if i can use i don't need to buy a set of SS for a mild 383 (cast crank).. So the main thing is is the duty cycle as good or better as the SS valve's ??? Thanks
I have run sodium filled exhaust and titanium intakes on 8000+ rpm engines where they definately benefit. I really couldn't recommend usuage for under 8000 rpm.
My experience has also showed valve face cracking under extreme conditions ; when stainless would have survived.
About those sodium filled exhaust valves... Why are they used?
ZD - Sodium is a metal at room temp. It was an idea thought up for aircraft motors around WWII. At least that's the first time frame I've ever read about using them.
The exhaust valve is subjected to teriffic heat especially in compressed air intake systems. Metal fatigue and just pure hot gas errosion is a fact of the poor exhaust valves life.
So anyway along comes some genius. He figures out that if you make the valve head and stem hollow and half fill it with sodium that will melt at very low temps. Then your using the liquid pulling the heat out of the head and face of the valve and transfering it stem and guides as you shake the valve up and down at 1000's of times per minute.
[QUOTE=gkull]ZD - Sodium is a metal at room temp. [QUOTE]
Sodium is a metal at all temperatures. The key is that's its melting point is about the same as water. At room temperature it is soft and pliable - like a firm putty and can be cut with a knife.
When it melts the valves reciprocating motion causes it to wash up the valve stem and transfer heat away from the valve head. Since it's a metal it has good heat transfer and thermal capacity properties.
LS6 and LS7 both use a sodium-potassium alloy inside the valve for cooling. Potassium melts at about 144F.