Hollow Stem Valves

[JCChildress]

How long do most of y'all run hollow stem valves in Super Stock ? This is a 327 stick car. Just curious how many runs most get out of them.

[JeremyDuncan]

Originally Posted by JCChildress

How long do most of y'all run hollow stem valves in Super Stock ? This is a 327 stick car. Just curious how many runs most get out of them.

We don't. Besides a very few exceptions(some 428 CJ) hollow stem valves are illegal in traditional SS & GT.

[bubski]

Originally Posted by JeremyDuncan

We don't. Besides a very few exceptions(some 428 CJ) hollow stem valves are illegal in traditional SS & GT.

You sure ?? the nice people at patterson are advertising hollow stem valves in thier SS engines !! Wheres the stock ,super stock police on this one ?? Billy ?? the damage is done !! More egregious than the 283 intake travesty !!

[SSDiv6]

Section 11A, page 3, Stock Cars, Cylinder Heads:

"Any aftermarket steel valve permitted, must retain stock head and stem diameters. Only engines OEM-equipped with sodium-filled valves may use sodium-filled replacement valves. Titanium prohibited."

Super Stock Section 12A, page 2

"Any aftermarket steel valve permitted; must maintain stock head and stem size; titanium valves prohibited. (OEM sodium-filled valve may be replaced with titanium, provided weight is equal to or greater than original.)

The current rule as written for Stock, can be interpreted that as long as they are Steel and not Sodium Filled or Titanium, they are acceptable.
For Super Stock, Sodium filled can be replaced with Titanium.

[JCChildress]

I appreciate the response. I knew they were legal, but I was just trying to see how long folks run them before they replace them.

[Mike Mans]

Well for some quick comparison, Stainless is about 30% stronger than Titanium - and we run our Ti valves in modified about 250 runs at least. I wouldn't have a problem running a stainless hollow stem 300+ runs if you've got a stable valvetrain that doesn't kill springs and make it impossible to get the keepers out of the retainers when you pull it apart.

A Manley and Ferrera hollow-stem valve has around .080"+ wall thickness, so you've got plenty of meat in there. They aren't making anything on the edge from what I've seen.

Mike

[Mike Pearson]

I would be afraid to run hollow stem valves in my engine. I have had issues with the Manley exhaust valves dropping the head off and killing the engine. Now I change the valves every time I freshen the engine if they have around 75 runs on them. Not worth the risk.

[Jim Hanig]

Originally Posted by Mike Pearson

I would be afraid to run hollow stem valves in my engine. I have had issues with the Manley exhaust valves dropping the head off and killing the engine. Now I change the valves every time I freshen the engine if they have around 75 runs on them. Not worth the risk.

Mike how much spring pressure do you run? your scaring me .

[Hacksaw]

I know it was a few years ago that Manley had a bad run of valves and the heads were falling off. Had nothing to do with spring pressures.

[Mike Pearson]

Originally Posted by Jim Hanig

Mike how much spring pressure do you run? your scaring me .

About 320 seat. Comp triples.