Chapter 3: Transmission Geometry, CV Joints, Stuffing Boxes, and Engine Mounts and Beds
Figure 3-9.
Universal
joint shaft
configurationsCVs (and most CV joints) should have a mini-
mum^1 / 2 -degree angle at each joint. Further,
there are maximum installation angles for CV
joints (and U-joints too). Be sure to follow the
manufacturer’s recommendations.
Whether using universal joints or modern
CV joints, the shaft or the close coupling
should be splined, enabling it to telescope,
thus absorbing axial changes in length. This
truly allows the engine to float, and it absorbs
the changes in shaft length that universals,
especially, can introduce at high angles. In-
stead of using a telescoping shaft, Aquadrive
CVs have axial movement built into the CV
joints themselves. The axial play ranges from
approximately^1 / 4 inch (6 mm) on the small
Aquadrive joints, to well over 1 inch (25 mm)
on the larger models.
A practical example of the advantages of
a modern CV joint occurred on a 60-foot
(18.2 m) aluminum motor cruiser I designed.
The builder did a fine job in general, but had
installed the engine compartment overhead
and insulation 4 inches (100 mm) lower than
we had drawn. As a result the forward upper
end of the engine was poking up through the
overhead. It would have been costly to re-
work the overhead, so we cut down the alu-
minum engine mounts instead and installed
the engine at a flatter angle. This could never
have been done with a straight-shaft system,
but we had already specced Aquadrive. In-
deed, this couldn’t even have been done with
standard universal or Cardan joints as the
carefully worked-out equal angles would
have been ruined. With the modern double