Racepak
Racepak
Racepak
Racepak
949-709-5555
www.Racepak.com
Hardware Installation: Driveshaft Sensor
and Collar
A drive shaft rpm sensor and mounting bracket used to mount the sensor to the vehicle are included in the
Sportsman Kit. However, the drive shaft split collar is sold separately. These collars can be purchased direct from
Racepak and are offered in many different sizes to accommodate multiple yoke configurations. These collars are
available with either two or eight magnets. The rpm sensor is a magnetically sensitive sensor that is polarity
sensitive each time a magnet passes in close proximity.
The first step in installing the kit is to determine where the split collar will be mounted. Normally the split collar is
mounted on the pinion shaft/yoke. However, it can also be mounted on the transmission tail shaft/yoke. If your
transmission and/or bell housing is removed frequently, you should mount the collar on the pinion shaft/yoke. Thus
avoiding possible damage to the sensor during clutch, and/or transmission service.
After you have selected a location, position the split collar over the shaft, and fix the collar onto the shaft by
tightening the two bolts connecting the two collar halves. Tighten the two bolts equally such that the gap on both
sides of the split collar is equal. This will ensure the magnets are 180 degrees apart.
Next, secure the mount bracket, and rpm sensor to the vehicle as shown below. The mount must be installed to a
solid member of the vehicle that does not move relative to the placement of the split collar assembly. This will
prevent contact between the sensor and the split collar. Insert the rpm sensor in the slotted hole in the mount
bracket, and position the rpm sensor such that the sensor is centered over the magnet in the split collar. Next,
adjust the gap between the end of the rpm sensor and the split collar between .050” to .100”. Secure the sensor by
tightening the two jam nuts located on the sensor.
NOTE: SPLIT COLLARS ON CARS USING A COUPLER
When the driveline is equipped with a coupler rather than a U-joint, the best location for mounting the split collar often changes. Because most of the
couplers have the female portion mounted on the pinion, and the radius on the backside tapers right to the pinion seal, this does not leave any room to
mount a split collar in the traditional location. In this case, we must move the split collar forward onto the male portion of the coupler.
When mounting the split collar on the male half of the coupler a new problem arises. This portion of the coupler needs to have some longitudinal
movement in order to function properly. It must be able to slide forward and backward a small amount. This presents a problem for the split collar in
trying to keep the magnets positioned under the sensor. When the magnet moves out from under the sensor, the signal is lost and the drive shaft RPM
is not recorded. In order to avoid this problem, Racepak has made collars that contain two pairs of magnets (total of 4). Each pair of magnets is
mounted longitudinally (inline) on the collar, which allows it some freedom to move without the sensor losing contact with a magnet. In most cases,
the male portion of the coupler will have two outside diameters.
These collars are sold separately and are available directly from Racepak.
8
Note:
If you are using a collar other
than the one supplied by Racepak
you can use the supplied magnet
with the sensor to test the polarity
of the magnets in the collar
.050 to .100 clearance
between sensor and magnet
Sensor
U-Joint Yoke
Rear
End
MEASURE YOKE
O.D. HERE
Yellow Painted End
INCORRECT
Magnets
will repel
each other
CORRECT
Magnets
will attract
each other
Magnets
Yoke is shown separated from pinion.
In most cases, installation does not
require yoke to be removed
H
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