Hollow Camshafts.....
Thread Starter
Instructor
Joined: Apr 2002
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Hollow Camshafts.....
As I have read, the stock cam is rifle bored, and is hollow.
A lot fo motorcycles have gone to hollow camshafts in order to lose weight and make for a lighter valvetrain in OHC applications.
From the things I have read about the LS1, it was done to lower NVH.
So....
All you guys who are running aftermarket cams, are they hollow as well?
Or are they lopey enough so that the NVH aspect of a more aggressive cam is cancelled out?
A lot fo motorcycles have gone to hollow camshafts in order to lose weight and make for a lighter valvetrain in OHC applications.
From the things I have read about the LS1, it was done to lower NVH.
So....
All you guys who are running aftermarket cams, are they hollow as well?
Or are they lopey enough so that the NVH aspect of a more aggressive cam is cancelled out?
Safety Car
Joined: Jan 2000
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From: Midlothian, VA
Re: Hollow Camshafts..... (99 Corvette)
The stock cams are hollow (don't remember why) and the Z06 valves are sodium filled (not hollow) :cheers:
Jerry
Jerry
Melting Slicks
Joined: Nov 2000
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Re: Hollow Camshafts..... (99 Corvette)
The stock cams are hollow (don't remember why) and the Z06 valves are sodium filled (not hollow) :cheers:
Jerry
Jerry
"With the higher lift, we needed to reduce the mass of the valvetrain or start getting into a float condition," John Juriga commented. "We went to hollow stem intake and exhaust valves, very similar to what we used in the ’96 LT4. We pushed the edge with a state-of-the-art, 0.8-mm. (valve stem) wall thickness–very thin stuff. The exhaust stems are sodium-potassium filled."
They would have to be hollow to fill them with something, eh? :D
Racer
Joined: Feb 2001
Posts: 286
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From: Bayville NJ
Re: Hollow Camshafts..... (DucaT)
My guess for the hollow cam is that it's hollow because it can be. GM finally started making cams with bigger journals (the LS1 is 55mm). This allows a lot of advantages. Base cirle is bigger. That means lower presure angles and quicker accelerations without negative radius flanks. The cam is stiffer so natural frequencies are raised a bunch. Whole valvetrain is more controllable. Which brings me to the hollow core. There's so much camshaft now, they don't need the middle any more.
Team Owner
Joined: Jun 2001
Posts: 100,672
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From: Cleveland OH
Re: Hollow Camshafts..... (99 Corvette)
The stock cams are hollow (don't remember why) and the Z06 valves are sodium filled (not hollow) :cheers:
Jerry
Jerry
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Re: Hollow Camshafts..... (Walt Donovan)
My guess for the hollow cam is that it's hollow because it can be. GM finally started making cams with bigger journals (the LS1 is 55mm). This allows a lot of advantages. Base cirle is bigger. That means lower presure angles and quicker accelerations without negative radius flanks. The cam is stiffer so natural frequencies are raised a bunch. Whole valvetrain is more controllable. Which brings me to the hollow core. There's so much camshaft now, they don't need the middle any more.
Melting Slicks
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Re: Hollow Camshafts.....
I've installed numerous aftermarket cams in LS1's and LS6's... from Lunati, Comp Cams, and Crane.. all were rifle bored..
Thread Starter
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Joined: Apr 2002
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Re: Hollow Camshafts..... (NewVetteLover)
Great, Thanks neverenuf
That was exactly the answer I was looking for.
I am not really sure if I understand why they are hollow beyond the weight advantage. Yeah, OK, the cam is larger and so now it is strong enough so that it can be hollow.
Like I originally posted, I can't figure what the hollow part has to do with the Noise/Vibration/Harshness aspect.
Whatever the advantage is, I'm glad that the aftermarket cams have included that in their construction.
Thanks fellas...........
That was exactly the answer I was looking for.
I am not really sure if I understand why they are hollow beyond the weight advantage. Yeah, OK, the cam is larger and so now it is strong enough so that it can be hollow.
Like I originally posted, I can't figure what the hollow part has to do with the Noise/Vibration/Harshness aspect.
Whatever the advantage is, I'm glad that the aftermarket cams have included that in their construction.
Thanks fellas...........
Melting Slicks
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Re: Hollow Camshafts..... (DucaT)
I'm told that the hollow bore is a stress relieving process and that it allows the heat treatment to be more effective..
