Steven,
>From my own work and seeing what was done on your polished rockers
I can say that the areas that were lightened make nearly no difference
in the inertia of the valvetrain.
I can see that the meat under the rocker has been ground away as well as
small amounts of metal at other regions of the rocker.
The bulk of the mass reduction is in the least desirable place, that is
that the mass was nearest the pivot point of the rocker.
This really wont enhance higher RPM opperation, the effect is negligable.
The work involved in "lightening" the rockers is definately NOT worth
the trouble.
So if the mass reduction is essentially useless, the only other functional
reasons for the polishing relates to stress relief, and making the oil
come off easier.
Thanx to all who responded to my rocker inquiry.
Steven you can titanium retainers that can be modified to fit your engine.
This is definately a significant reduction in mass.
Other worthwhile valvetrain mass reductions were...
1) Bigger yet lighter Z-car valves.
2) Crane cams springs (higher rate and preload, yet lighter too).
Jarrid Gross
-----Original Message-----
From: owner-alpines@autox.team.net
[mailto:owner-alpines@autox.team.net]On Behalf Of Steven Silverstein
Sent: Friday, February 09, 2001 2:36 AM
To: Sunbeam
Subject: Polished Rocker fingers
I am finally back from classes.
Below is a close up photo polished rockers and there is a substantial amount
of material removed. These wereon the car when I bought it. Actually, I
should say, "with the car".I haven't measured the weight differences between
a regular rocker and one of the polished rockers but If I can find the extra
loose polished one I will and post the results.
I also have Isky pushrods, shortened lifters, and aluminum retainers which
in combination must make a significant difference in overall moving valve
train weight. Ironically, they (when it was raced in the 60's) limited the
car to 6000/6300 rpm.
The machine shop that I have worked with really recommends against the
aluminum retainers. The other option is to cut off the lower portion of the
retainer where the "O-ring" seal is located. Then use Perfect Circle seals.
I have found a few of this style retainer, too. I will have to weight the
differences between aluminum, steel cut down, and stock. I don't know how
much difference this all makes unless you are running higher rpms.
I guess the devil is in the details. I am sure it all added up to increase
longevity (stress relief of the rockers) and did remove some valve train
weight.
http://www.sunbeamalpine.org/racing/Web%20pages%20for%20Sports%20Car%20Forum
/Engine%20Rockers.html
Steven Silverstein
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