Hollow Stem Valves
Thread Starter
Racer
Joined: Sep 2007
Posts: 333
Likes: 27
From: East Coast
Hollow Stem Valves
To All:
Besides the weight and the cooling effect(exhaust), what are the advantages/disadvantages of having hollow stem(intake) and sodium filled(exhaust) valves like in the LS6 heads? Stronger? Weaker?
Besides the weight and the cooling effect(exhaust), what are the advantages/disadvantages of having hollow stem(intake) and sodium filled(exhaust) valves like in the LS6 heads? Stronger? Weaker?
Safety Car
Joined: Sep 2007
Posts: 4,359
Likes: 6
From: Los Alamitos California
St. Jude Donor '09
I'll let a couple of others here chime in, but some feel the hollow stem valves aren't durable enough. The sodium filled valves are usually used for FI applications because of high heat.
San
San
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Very few fail on the hollow stems but the failure rate isnt zero. By construction they are 3 piece welded valves. Some will have you believe that failures of hollow stems are all due to installer error but aside from spring tension, there isnt anything adjustable in our valve train. In the event of a mechanical over rev or a weakened older spring, I would want a stronger valve in there if a piston does make contact. The failure rate while not zero should be compared to the failure rate of a stainless one piece valve which is zero.
My car runs a 2.165 stainless intake valve and since I can rev to 7100rpm without float with that heavy valve, there is no reason the stainless one piece valve shouldnt be chosen over a hollow stem. They are also cheaper than hollow stems.
My car runs a 2.165 stainless intake valve and since I can rev to 7100rpm without float with that heavy valve, there is no reason the stainless one piece valve shouldnt be chosen over a hollow stem. They are also cheaper than hollow stems.
Last edited by SpinMonster; Jan 4, 2009 at 06:56 AM.
Burning Brakes
Joined: Sep 2007
Posts: 903
Likes: 0
From: New Orleans LA
Very few fail on the hollow stems but the failure rate isnt zero. By construction they are 3 piece welded valves. Some will have you believe that failures of hollow stems are all due to installer error but aside from spring tension, there isnt anything adjustable in our valve train. In the event of a mechanical over rev or a weakened older spring, I would want a stronger valve in there if a piston does make contact. The failure rate while not zero should be compared to the failure rate of a stainless one piece valve which is zero.
My car runs a 2.165 stainless intake valve and since I can rev to 7100rpm without float with that heavy valve, there is no reason the stainless one piece valve shouldnt be chosen over a hollow stem. They are also cheaper than hollow stems.
My car runs a 2.165 stainless intake valve and since I can rev to 7100rpm without float with that heavy valve, there is no reason the stainless one piece valve shouldnt be chosen over a hollow stem. They are also cheaper than hollow stems.
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