Milodon Gear Drive - Full Cover Style 12000-12250, 12600-12900, 13000-13250 - Manual (Page 2)

chevrolet gear drives. The modifications allows the balancer to move outwards away from the
cover. However, in some cases such as when a stock type balancer is being used, the balancer
may need to be machined approvimately, 150-.160 (as shown in figure #1) to attain the desired
pulley alignment.
TIMING THE ENGINE
Once gear drive has been properly installed as far as lash adjustment, we can now proceed to the
timing. There are no dots or line up marks on our gears because these are usually inaccurate.
We start by finding the exact "straight up pattern" (no advance or retard). Once this position has
been found, advancing or retarding cam timing can be done quickly and accurately without
messing around with offset bushings and keyways. All Milodon gear drives use our venieer cam
bolt pattern to set and adjust cam timing.
With the engine disassembled, install cam hub, less the cam gear, on the cam and crank gear on
crank snout. Install degree wheel on crank and set indicator on T.D.C. for #1 cylinder. Using
cam manufacturer's specs, find the #1 intake opening and move crank to that position. Place dial
indicator on #1 intake and open to what the cam manufacturer used for a checking clearance.
For example, if the cam specs were intake opens at 39 degrees BTDC at .050" cam lift, you
would set the crank degree wheel at 39 degrees and the dial indicator on #1 intake at .050" lift.
The cam and crank are now in the "straight up" position set EXACTLY with 0 degrees advance
or retard. The cam gear is now installed onto the cam hub, with no bolts as yet. It will engage
idler gear teeth and allow the cam gear bolts to exactly align with hub bolt holes in only one
position. (There are 7 bolt holes and, therefore 7 possible positions). Once the correct cam gear
to hub position has been found, install all seven cam gear bolts. These should be torqued to 22
ft/lbs.
Scribe an indicator mark on the cam hub adjacent to any cam gear bolt hole. Mark that bolt hole
with #1. Going clockwise mark the other bolt holes #2 - #7. Now using the chart supplied, you
can advance or retard the cam to any position, from any position. There will be two tooth
locations possible for each bolt hole position. The one for which the cam must be rotated
clockwise to align holes will advance the cam. The one for which the cam must be rotated
counterclockwise will retard the cam.
The Milodon “Gear Drive Install and Cam Degree” video gives clear and easy to under stand
direction, if needed. Contact your parts supplier for part # 14900.
Position # Advance Retard
1 0 0
2 6.5
7.5
3 12 2
4 4 10
5 10 4
6 2 12
7 7.5
6.5