Scout Racing Cam Profiles
$175.00 per set of cam lobes.
I found it necessary to come up with my own new performance cam
profiles, because they are just NOT available anywhere (untill now!). After
determining the physical characteristics of the cam chest, I concluded that
.422" lift is the practical limit for a Scout motor. I have designed so far (8)
seperate cam lobe profiles (4 for Street/Strip, and 4 for Land Speed Record
Racing, that can be used for dirt track racing as well). I first started by
designing cam lobes that were similar to the "Shunk Daytona Racing" cams, which
have a large rounded lobe circle, and concave lobe flanks that dish inwards.
After much consideration, I am looking at more modern shapes that are more flat
sided as well. The dished lobe flanks get to maximum lift too quickly, and can be hard
on valve train components. I have a set of the Shunk Daytona Racing cams in both
my Stroker Scout, and my Super Chief, and the performance is very strong! My SS1
cam will show similar performance. I have chosen to use John Andrews of Andrews
Cams to custom grind some of my lobes, and Andrews Cams is a very good choice for cam
lobes. They can take my target lift data, and durations at the .050" lift
locations, and their computer will design (and grind) the best profile for both
performance, and longevity.
My Street/Strip cams (SS1 & SS2) will both have
.390" lift (which should require no modifications to the motor to install them).
The "SS1" cam will have 245 degrees duration at the .050" valve lift locations,
while the "SS2" will have 250 degrees. Both will be very hot for street, and the
"SS1" should have a little better low end, while giving up a little bit of top
end power compared to the "SS2" cam. My (3) Land Speed Racing cams (LSR1, LSR2,
and LSR3) will all have the max lift of .421" valve lift, and will vary in
degrees of duration. The higher lift will require some trimming of metal inside
the cam case. The pinion bushing aluminum boss already has (2) clearanced areas
that need to be enlarged by about .020", so the cam lobe won't hit the case.
Plus the rear cylinder's push rod guides need to have their exposed bottom
portions showing in the cam chest ground off clear to the base aluminum, or the
lifter will hit them. The LSR1 will have 255 degrees at the .050" valve lift
locations, while the LSR2, and the LSR3 will have 260, and 265 degrees
respectively. These cams will be very hot! These durations are somewhat less
than those used in drag racing. I am trying to preserve a good portion of torque
that is needed at Bonneville. Cams that work well at Bonneville work well in
road racing, and dirt track racing as well, where strong mid-range power is
needed to pull away from turns. All of my cam lobes will be drilled for the 1/4"
hole to pin the new lobe to the cam/gear that has the old lobe ground off,
except it is shifted to one side of center by 2 1/2 degrees of crank rotation to
advance the cam for better low end. "Pop Shunk" always had his cams slightly
advanced, while Ollies weren't. To precisely control a cam's advance position, I
like to make special off-set pins for installing the cam lobes.
Initially I am
making only replaceable cam lobes, that need to be installed to original gears.
Later I will have complete "cam-on-gear" assemblies like factory cams, but for
right now, I am making seperate lobes only to serve my Bonneville project. I
prefer seperate lobes, because I have better control over the cam timing. Other
people that don't want the extra work of seperate lobes will appreciate the full
assemblies, but there is no control of timing available. They will average a 2 1/2
degree advance position, and any error from there will be attributed to your
component error.
Here you can see my racing lifters in the cam case with (2) of my early
dished flank cam prototypes.
See my "Tech Talk" section for instructions on installing cam lobes.
CONTACT INFORMATION:
James R. Mosher
(505) 466-7870
