Don:
The smaller lateral valve loadings are only part of the advantage.
The frictional losses associated with rotating the rocker around
the rocker shaft also are eliminated, and the frictional losses
at the rocker tip are eliminated.
The net result is more power by virtue of the reduced
losses. Reduced lateral loadings on the valves and extended
valve guide wear are just gravy. If you are a racer, you also
appreciate the fact that roller rockers can function with
reduced or no lubrication, which means a bullet proof top end.
Roller rockers also tend to be much more accurate, so
that cylinder to cylinder matching is improved. This allows
you to push the whole setup to the hairy edge of detonation
without one cylinder acting up before the others. This is
improved margin for 'pushing the envelope' for the gear heads
out there.
The disadvantage is cost, as always.
Cheers,
Vance
------------------------------
1974 Mimosa Yellow Triumph TR6
Cogito Ergo Zoom
(I think, therefore I go fast)
-----Original Message-----
From: Don Malling [mailto:dmallin@attglobal.net]
Sent: Tuesday, January 07, 2003 6:54 PM
To: 6-Pack
Subject: Valve lift and lateral forces on the valve guides
List,
I understand that one of the advantages of roller rockers is that they
reduce or eliminate lateral forces on the valve guides at higher valve
lifts.
At what valve lift does this become important? For example, if I have a
cam with .425 valve lift using stock 1.45:1 rockers, do I have a
problem? How much valve lift can I have before I start needing roller
rockers. I understand this is not a binary thing -- If I have a little
too much lift I will have a little too much wear. Lots of lift, means
lots of wear. I have no feel for the range -- little problem to big
problem.
Thanks,
Don Malling
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