This question was raised a couple weeks ago. I thought is was time for
a technical discussion. A couple years ago I decide to measure the
rocker ratio. Using a dial indicator and degree wheel, I measured the
lift curve at the cam (no rocker assembly). Then I installed the rocker
assembly and measured the lift curve at the valve. I took the ratio of
the two curves and got the graph at
http://home.swbell.net/cartrip/RockerRatio2.gif . I was surprised and
confused by the fact that I did not get a horizonatal line. Later I
realized I'm looking at compression of the valve train. After measuring
the valve springs constant and installed spring pressure, I was able to
estimate a valve train stiffness of about 60,000 lb/in. Sounds like a
big number, but with 100 lbs of seat pressure (150 lbs at the cam), you
get 2.5 thousandths deflection. I guess this sort of thing is common
knowlege in mechanical engineering circles, but it was news to me. So,
even though the rocker ratio is 1.49 you don't see that much more lift
at the valve.
EDWARD BARNARD wrote:
>My documentation is showing two different numbers for the stock ratio. One is
>1.49/1 the other is 1.5/1. Hope that is some help. - Ed
>
>Stutzman <stutzman@adelphia.net> wrote:what is the TR3/4 stock rocker ratio? I
>always thought it was 1.4 but I can't
>find it in the manuals.
>bruce stutzman
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