Don,
Thanks for the great information again!
I pulled the intake manifold and tried to get a dial indicator on the
lifter body. I could not get to the cam lobe with the dial indicator I
have.
The dial indicator could not get a straight shot at the lifter but after
several tries I did get consistant readings of 0.318" on and intake
lifter. IF I have a reasonably good reading it looks like the cam is
somewhere around 0.477" lift. This is a little more than I would
probably like for a street only car but I'm not going to change it.
If I do change it in the future what is a nice cam for good low end
torque street only application with reasonable fuel economy? This is a
383 with a 4-speed. I am planning on installing a 3.23 rear.
Thanks
Dennis C.
Don Dulmage wrote:
lobe lift (off the pushrod since that is working for you) X 1.5 -.006=
net
valve lift for hydraulic cams. Because a hydraulic lifter bleeds down
it is
almost impossible to get a lift figure using it.. If you had adjustable
rockers you could pop in a solid lifter and set it at zero lash. The -
.006
and the amount the hydraulic lifter sucks up in the process of
absorbing
the wack. BUTTTTTTTTT if that was a solid cam there would not be .006
but
.024 to .032" valve lash.
Since we are on the subject anyway let me say Cam specs area given even
for
solids at .000" lash for most manufacuturers. No one thinks of this so
they
run a .510 list solid lifter cam thinking that will be better than a
.510
lift hydraulic forgetting in the process that the solid cam specs are at
.000" lash and in reality that cam will have only .486 lift with its
.024
valve lash whu ile its hydraulic twin will give the whole .510" minus
about.006 for 504" lift in actual running conditions. On top of that the
solid cam has long ramps to ease the lifter up snug and let it down so
it
doesnt bounce . These take up about 7 degrees either end of the lobe so
it
wastes about 14 degrees total duration just getting ready to work. The
hydraulic doesnt need this since it is right there snug on the end of
the
pushrod all the time so less duration is required for the same RPM.
range.
That is why we often compare durations at .050" and .100" and even .200"
just to make sure what we are actually gettting. So whay do we use
solids?
Because first years ago before the late sixties it was not possible to
turn
higher Rpms with hydraulics so solids were an automatic choice. Even now
my
Max wedge never sees above 6500 . It doesnt need to so i run a hydraulic
cam
of similar lift and duration as the old Max Wedge solid cam but I get
more
performance for the above reasons. Since i never need to go to 7000+ it
is
for me a no brainer.
Now i know your buddies with their little duntov corvettes and such will
get
ticked off if you try and explain this to them and those who are in love
with solids will also. That is the wonderful thing about the truth. It
doesnt matter who believes it. It is not a demoratic function based on
votes. It is just the truth , period. Sometimes in a racecar you cant
find
a cam you like in hydraulic grinds and so you search solids keeping in
mind
the principles mentioned above. If you do your math right and allow
extra
duration and extra lift because of the ramp thing and the valve lash, it
works. If not it doesnt.
----- Original Message -----
From: "Dennis C." <dennis.2914@xxxxxxxxx>
To: <1962to1965mopars@xxxxxxxxxx>
Sent: Monday, January 26, 2009 12:45 AM
Subject: Cam Questions
>
> Hello,
>
> Does anyone know what the stock rocker ratio is for a 383?
>
> Do the stock rockers have the same ratio for intake and exhaust?
>
> And last, is it possible to get a rough idea what the lift is of an
> installed cam with hydraulic lifters by reading the lift at the pushrod
> end of the rocker with a dial indicator? I can not reach the valve end
> of the rockers with my dial indicator stand.
>
> Any help will be appreciated.
>
> Dennis C.
>
> 1996 Dodge Ram 3500 Van Conversion
> 1964 Plymouth Belvedere 318 Auto
> 1963 Plymouth Sport Fury 383 4-speed
> 1949 Dodge Pickup 289/C4 soon to be changed
> 1998 Honda Valkyrie Standard
>
>
> ----
> Please address private mail -- mail of interest to only one person --
> directly to that person. I.e., send parts/car transactions and
> negotiations as well as other personal messages only to the intended
> recipient, not to the Clubhouse public address. This practice will
> protect
> your privacy, reduce the total volume of mail and fine tune the content
> signal to Mopar topic. Thanks!
>
> '62 to '65 Mopar Clubhouse Discussion Guidelines:
> http://www.1962to1965mopar.ornocar.org/mletiq.html.
>
>
1996 Dodge Ram 3500 Van Conversion
1964 Plymouth Belvedere 318 Auto
1963 Plymouth Sport Fury 383 4-speed
1949 Dodge Pickup 289/C4 soon to be changed
1998 Honda Valkyrie Standard
----
Please address private mail -- mail of interest to only one person --
directly to that person. I.e., send parts/car transactions and
negotiations as well as other personal messages only to the intended
recipient, not to the Clubhouse public address. This practice will protect
your privacy, reduce the total volume of mail and fine tune the content
signal to Mopar topic. Thanks!
'62 to '65 Mopar Clubhouse Discussion Guidelines:
http://www.1962to1965mopar.ornocar.org/mletiq.html.
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