Exhaust Valves

[opeltwinturbo]

Now that I managed to bend six exhaust valves when I took out the motor, its time to replace them. I tried beating them straight with a hammer but that didn't work.

Two questions: 1. What is the correct valve length. How much should be above the retainer. 2. Should I replace them with S/S or titanium.

 

[JoyOf6]

Now that I managed to bend six exhaust valves when I took out the motor, its time to replace them. I tried beating them straight with a hammer but that didn't work.

Two questions: 1. What is the correct valve length. How much should be above the retainer. 2. Should I replace them with S/S or titanium.

John,

I measured 5.42" total length on a GM S2 exhaust valve. FWIW, I wasn't sure what I wanted to use last winter but decided on Ferrea superalloy for exh on my S2 heads.

The "Steers and Queers" may have their own ideas. I'll check around here and get back to you.

Art

 

[opeltwinturbo]

that Boys From Texas. "only Two Things Come From Texas"......lg

 

[NastyGn]

Hey, Hey, Hey, Now.

I also had the Ferrea valves in the GN1's. I had issues with the S/S valves bending or I should say the valve itself sagging or deforming from being pulled up into the head, after a number of runs and adjusting the valves to correct lash made it worse. I was told by the head guy to stay away from the titanium valves because they are to hard and will not bend but break apart and cause more damage.

Also for most of us down here having horns is required

 

[EightSecV6]

I use titanium ,those suckers are light and we really dont run them long enough for the heat to bother them. There are many different lengths that will work as well as install heights (retainer location) as well as different degree locks.
Sorry,not much help!

 

[Big Stu]

Of course I don't have a running stage motor, but.... Titanium if you don't plan on putting that many runs on the motor before changing them out. Inconnel is also supposed to be very good.

 

[EightSecV6]

Inconnel is the best but HIGH RENT! I think the titanium last as well as any in a race engine, I wouldnt consider them for a street car.

 

[GARY HARVEY]

Enkonelle"= French for peso's.

 

[ChrisChow]

Titanium has a short life cycle in a turbocharged motor. Speaking about exhaust valves only. Mine go bad every season. Not all of the valves go bad, but a few. I'd like to try the Sodium-Potassium filled exhaust valves next time and see if that helps.

 

[10SV6]

Chris, What material are your exhaust valves ?

 

[lazaris]

I used a tuliped Inconnel.

 

[ChrisChow]

Chris, What material are your exhaust valves ?

At the moment, I have all titanium exhaust valves from Del West.
It's a once a year maintenance item to remove and check them.

Previously, I've tried Ferrea, Manley...exhaust valves in "super alloy" and HD stainless alloy XH-428. But a few have slightly tweaked after a full racing season.

 

[EightSecV6]

Titanium has a short life cycle in a turbocharged motor. Speaking about exhaust valves only. Mine go bad every season. Not all of the valves go bad, but a few. I'd like to try the Sodium-Potassium filled exhaust valves next time and see if that helps.

Chris,
When you say they go "bad" what are you actually referring to? I have seen some mionr flaking on the stems but have never torn one up.

 

[ChrisChow]

Exactly waht I've seen on the Titanium valves (exhaust). Flaking on the stems where they just exit the guide in the exhaust port.

To be more specific when we put the all the exhaust valves in a valve milling machine/fixture, 2 or 3 valves cannot be refaced (the area where the valve contacts the seat) becuase the stem or the tulip area have stretched...making the valve eccentric.

Chris,
When you say they go "bad" what are you actually referring to? I have seen some mionr flaking on the stems but have never torn one up.

 

[opeltwinturbo]

How concerned do the head guys get if the intake valve is recessed below the exhaust valve.

 

[GARY HARVEY]

Fwiw

Inconell is the material of choice for performance applications.
From a tech standpoint, having them cryo'd and the head ceramic coated has demonstrated to aid in scuff and heat maintance/control. It is a added process(s) that has been used for years with budget minded racers that are tech oriented.

For those with unlimited budget, Titanium is the material of preference. It is lighter, does an excellent job but has duty cycle limit(s).

Mr. Chows experience with stretch, is a good case in point.

IMO

 

[EightSecV6]

How concerned do the head guys get if the intake valve is recessed below the exhaust valve.

Detonation will cause the valves to "sink" in the heads, sometime stretching them, sometimes pounding the seats in. Have your heads always been like this or has something changed? Maybe new seats have been installed in which case I would consider this normal.