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-   -   Hollow stem intake valves (https://classracer.com/classforum/showthread.php?t=66961)

SDT1DYI 07-22-2017 11:03 AM
Hollow stem intake valves
 
Are hollow stem intake valves legal in stock if they were not OEM for the engine? As well is it legal to change valve stems sizes in stock but keeping the same valve angles?

ss3011 07-22-2017 11:26 AM
Re: Hollow stem intake valves
 
In the rule book , it says "Any aftermarket steel valve permitted, must retain stock head and stem diameters" . Says nothing about hollow stems being illegal .

Alan Roehrich 07-22-2017 07:30 PM
Re: Hollow stem intake valves
 
Quote:
Originally Posted by SDT1DYI (Post 539939)
Are hollow stem intake valves legal in stock if they were not OEM for the engine? As well is it legal to change valve stems sizes in stock but keeping the same valve angles?

It is NOT legal to change valve stem size. Not in Stock Eliminator or Super Stock.

But hollow stem valves are legal, even if not originally equipped. We run them in everything, we use Ferrea.

ss3011 07-22-2017 07:48 PM
Re: Hollow stem intake valves
 
In Super Stock the valve stem needs to be the stock size , but aren't you allowed to use necked down stems near the valve head , like the Manley "Pro-Flo" style valves ?

Alan Roehrich 07-22-2017 07:51 PM
Re: Hollow stem intake valves
 
Quote:
Originally Posted by ss3011 (Post 539974)
In Super Stock the valve stem needs to be the stock size , but aren't you allowed to use necked down stems near the valve head , like the Manley "Pro-Flo" style valves ?

Yes, they can have an undercut stem behind the head of the valve.

SDT1DYI 07-22-2017 11:59 PM
Re: Hollow stem intake valves
 
Titanium valves can not be used but are titanium retainers legal?

Todd Gross 07-23-2017 11:10 AM
Re: Hollow stem intake valves
 
Section 10A says "Titanium prohibited". Although that's vague and you don't know if they're referring to valves only or all of valve train. But I know when the Drag Paks came out they had titanium retainers and were allowed one year to remove and replace with steel (I read that anyway). Everyone uses lightweight tool steel retainers for the most part.
Quote:
Originally Posted by SDT1DYI (Post 539993)
Titanium valves can not be used but are titanium retainers legal?

SSDiv6 07-23-2017 03:46 PM
Re: Hollow stem intake valves
 
Quote:
Originally Posted by SDT1DYI (Post 539993)
Titanium valves can not be used but are titanium retainers legal?
Titanium valves can be used in Super Stock classes as a replacement for OEM engines that had Sodium filled valves.


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