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Re: Vaccuume Advance - Rebuild with Hot Cam and Roller Rockers?

To: David Hall <>
Subject: Re: Vaccuume Advance - Rebuild with Hot Cam and Roller Rockers?
Date: Wed, 05 Mar 1997 10:58:00 -0800 (PST)
As the rockers "tilt" and push down on the valves there is a horizontal 
component due to the fact that the rockers are pivoting on an axis. When you 
put in a cam with higher lift, the horizontal component of force applied to 
the valve increases. This can cause increased wear in the valve guides and 
on the lobe of the rocker. In addition, the friction associated with rubbing 
the rocker lobe back and forth accross the valve stem robs power and causes 
wear on the rest of the valve train. To overcome this the roller rocker has 
a roller on the end of the rocker where it contacts the valve stem 
eliminating the effects of the horizontal component and reducing the 
friction in the valve train.You can change the valve lift by changing the 
cam or by changing the ratio of the rocker assembly. Really an unnecessary 
cost unless your doing some serious mods to your engine IMHO.

Chris Reichle
The main advantage of roller rockers is to lessen the parasitic losses
from the valve train. Our LBCs valve lift is pretty modest, not much
more than a third of an inch, but that still requires our little rockers
to tilt something like 30+ degrees. That is a lot of rotation and force.
The cups at the end of the pushrods keep everything in contact but there
is some stress there and the rocker shafts can wear. I don't know how
you would replace the bushings in those rockers. I guess it only takes

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