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02-07-2019, 11:13 AM
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#1 |
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Join Date: Apr 2007
Posts: 194
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Hollow Stem Valves
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.
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02-07-2019, 06:26 PM
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#2 | |
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Join Date: Apr 2010
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Re: Hollow Stem Valves
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02-07-2019, 11:15 PM
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#3 | |
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Re: Hollow Stem Valves
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02-07-2019, 11:35 PM
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#4 |
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Location: Glendale, Arizona
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Re: Hollow Stem Valves
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. Last edited by SSDiv6; 02-07-2019 at 11:40 PM. |
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02-08-2019, 11:02 AM
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#5 |
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Join Date: Apr 2007
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Re: Hollow Stem Valves
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.
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02-08-2019, 11:54 AM
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#6 |
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Join Date: Jan 2006
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Re: Hollow Stem Valves
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 |
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