Titanium valves....less spring pressure?

[kfxguy]

Well Im gonna order them. I just called wiseco and kibble white and asked if I could reduce spring pressure due to the lighter valve. Neither had a clue. Kibble white just kept recommending using the copper alloy seat. Well I'm not to concerned with that. The valves I'm buying are coated and the manufacturer says they will be ok with the stock seats. My main concern is easing up some spring pressure to:
-reduce friction and heat
-reduce wear on the valve and on the cam lobes
-help the cam journels last longer.

So I have the kibble white spring setup right now. I wondering if I can omit the inner spring. Or maybe use a stock outer spring only. Or what combination may be lighter that a full on double spring setup. Maybe someone can ask eddy on thumpertalk if no one else knows.

[sandman74]

Even with lighter valves, wouldn't reducing the spring tension lower the float RPM???

How to Build, Modify & Power Tune Cylinder Heads - Peter Burgess, David Gollan - Google Books

[YOURADHERE]

Theoretically yes, since the valves are lighter you'd think you could get away with reduced spring pressure. The whole reason for heavier duty springs is to support the heavier valves. Look at it in a positive way.....you've have less of a chance for valve float.


Personally I wouldn't risk it and stick with the Kibblewhite springs or DRZE springs.

[TRMN8TR]

Like the others have said, valve weight is a small concern but valve float is a bigger issue. Exactly how much lighter are the valves, or won't you know till you get them?

When I built the engine for my car I put bigger valves in but they were lighter and I still had to put stronger springs in. I was also raising the rev limit by 1000 rpm so valve float was the bigger concern.

[ltz4-rum]

Spring pressure and valve weight have nothing to do with each other. Spring pressure is determined by max RPM the motor is intended to reach. The little bit of weight difference of the valves (a few grams) isn't worth worrying about. You will see no noticable difference in H/P or any other performance gain. The KW and Weisco valves are a good choice, but for durability only.

[TRMN8TR]

Well they do have something to do with each other, which is a lighter valve is technically easier for the spring to return. However, I agree that the difference in weight of a few grams is negligible.

[kfxguy]

Lol. It's more than just a few grams....

[kfxguy]

Originally Posted by ltz4-rum

Spring pressure and valve weight have nothing to do with each other. Spring pressure is determined by max RPM the motor is intended to reach. The little bit of weight difference of the valves (a few grams) isn't worth worrying about. You will see no noticable difference in H/P or any other performance gain. The KW and Weisco valves are a good choice, but for durability only.

I think I have to disagree with your first sentence. Heck most all of them except the last one. If you use lighter valve train, you need less spring pressure to control it (valve float). How could you possibly think that spring pressure is only affected by rpm. It has everything to to with weight, rpm and harmonics all at the same time. That why I had a small block chevy (383 stroker) that turned 7800 rpm in my daily driver. Because I made efforts to lighten the valve train as much as I could. And I used less spring pressure in the process.

[zookie400]

the valve weight is not what causes float (in an OHC engine), the spring compression/decomp speed is.

the spring is slammed down FAST and actually bounces up and down while the cam is lifting/lifted off the valve, and since the spring isnt holding solid the valve is not held tight against the seat. it actually wiggles and rotates and bends the valve stem all over when its happening.

another type of valve float is from heavy valvetrain components, but was more of an issue in the old pushrod and rocker engines. there were so many heavy components that carried a lot of inertia when high rpm/aggressive cam was thrown into the mix the massive amount of kinetic energy was enough to hang the valves open longer or open farther than intended, causing the piston to slap the valve back into its hole. this type of float is a non-issue with almost all OHC engines.

for a better understanding...watch:

Valve Float - YouTube

Valve Float - YouTube

in this video halfway through you can see slow motion of the valve inside the head, the bright green line can be seen dancing on the seat. after that they show the stem inside the guide bouncing around.

Short Valve Float Movie - YouTube

Short Valve Float Movie - YouTube

[beaverclever02]

Nice vids Zookie. I wish they would get together with some newer ameras and redo them

[kfxguy]

So are you trying to say its pointless to run titanium valves?

[z455]

[QUOTE=zookie400;786056]the valve weight is not what causes float (in an OHC engine), the spring compression/decomp speed is.

the spring is slammed down FAST and actually bounces up and down while the cam is lifting/lifted off the valve, and since the spring isnt holding solid the valve is not held tight against the seat. it actually wiggles and rotates and bends the valve stem all over when its happening.

If I read this right then a lighter valve would float less at high RPM's in that situation. If the valve is lighter than the spring could maintain more control of it at high R's and reduce the bouncing on the seat. As far as the moving in the stem, im not sure it would seem like a lighter valve would also be more controlled and stable in the guide.

IMHO I would weigh the valves to see how much of a difference there actually is. I would see that SEAT pressure could be reduced but I would try to keep the same "spring rate" so to speak.

Just went out and try to start my Z for 15 mins, Guess who needs new valves?

[kfxguy]

Well I have some ferreas I could sell you when they come in. They should get here tomorrow. I'll take a loss on them. I'm gonna do ti valves regardless. Lemme know if you want em.

[z455]

Pm me details. Thanks

[kfxguy]

I don't like these instructions...
http://www.wiseco.com/PDFs/Manuals/TitValveInstall.pdf