CHECKING CAMSHAFT TIMING
In order to check cam timing, you will need
some specialty tools. You will need a degree
wheel, dial indicator with magnetic base and a
heavy wire for a timing pointer. Choose a large
diameter wheel as they are easier to read and
more durable. Some manufacturers sell kits
with a rigid, adjustable pointer that mounts
easily to the front of the engine. The other
option is a heavy wire that is mounted to the
block and bent into position.
Start with placing the dial indicator and stand
on the right side block deck to measure travel
of the CENTER of piston number 1 (passenger
side, front). Bring number 1 to TDC (Top Dead
Center) by observing when the dial indicator
stops moving. Bolt the degree wheel to the
front of the crankshaft, and attach the pointer
to the front of the block so that the pointer
is positioned at the zero degree reading on
the wheel. To find exact TDC, first set the
dial indicator to zero at the point of highest
piston travel. Next, turn the crankshaft
counterclockwise about 90 degrees. Then,
slowly rotate the crankshaft clockwise (the
normal direction of engine rotation) until the
indicator is .030" below the TDC (zero) setting.
Note the reading of the degree wheel at this
point. Then, continue turning the crankshaft
clockwise past the TDC about 90 degrees.
Slowly rotate the crankshaft backwards
counterclockwise until the same .030" below
TDC is seen on the dial indicator. Again, note the
degree wheel reading. Next, rotate the degree
wheel so the pointer falls at the AVERAGE of
the two observed readings. Lastly, relocate the
pointer exactly over the zero reading of the
degree wheel, and you will have perfectly dialed
in TDC. Redo the procedure to satisfy yourself
that the setting is correct, and then proceed to
measure cam timing.
Install the number 1 cylinder intake lifter in
the proper lifter bore. Position the dial indicator
so the tip is on the edge of the lifter or in the
center of the lifter. Extensions for the dial
indicator may be necessary. Carefully line up
the dial indicator so the travel of the indicator
is linear to the lifter. Rotate the engine and
observe the action of the lifter. Make sure the
fully open and fully closed positions of the lifter
are within the travel range of the dial indicator.
Rotate the crankshaft until the lifter is at the
highest point of its travel, and set the dial
indicator to zero. Continue rotating the engine
clockwise until the lifter starts to travel up
again. Slowly continue until the lifter is
.030" below the point of maximum travel,
and note the reading of the degree wheel.
Start rotating the crank again until the lifter is
.030" below the maximum travel on the closing
side of the cam lobe. Note the degree wheel
reading. The AVERAGE of the two readings
taken is the location of maximum intake lift
ATDC (After Top Dead Center).
Compare this to the installation recommendation
of the cam manufacturer, as it should be
relatively close. The timing should be within
one degree of the recommended setting. If
there is a need to adjust the timing, FRPP has
multi-index timing chain sets which have nine
keyways to adjust cam timing.
NOTE: Many cam manufacturers provide
.050" lift cam timing information. To check
this, reset the dial indicator to zero with the
lifter at zero lift. Then rotate the crank in the
clockwise direction until .050" lift is shown on
the indicator. Note the intake open degrees.
Then proceed clockwise until the intake closing
at .050" lift is reached. Compare the readings
to the cam card. Together with the maximum
lift information, this data will tell you where the
cam is degreed. Once corrections are made,
measure the cam timing once more to verify
the fix was correct.[justify]