Milodon Gear Drive - Full Cover Style 12000-12250, 12600-12900, 13000-13250 - Manual

MILODON
2250 Agate Court
Simi Valley, Ca 93065
(805) 577-5950
GEAR DRIVE INSTALLATION
#12000-12250, 12600-12900, 13000-13250
Small Block Chevy, Big Block Chevy and Big Block Chrysler - Wedge & Hemi
Milodon makes three basic models of gear drives:
1. SUPER STOCK - to fit under the stock water pump.
2. UNBLOWN COMPETITION- includes fuel pump drive and adapter plate.
3. SUPERCHARGED ENGINE - includes fuel pump extension and drive.
INSTALLATION INSTRUCTIONS
(Chrysler engines must have a 3 bolt cam and not the stock single bolt.)
Remove the stock timing cover, chain and gear. These will not be used. Clean the face
of the engine and remove the stock dowel pins(2) from the block. Be sure to remove any nicks
or burrs on the front of the block. Place the three piece thrust bearing assembly on the camshaft
(washer-bearing washer). Place the hub on the cam. Secure with three (3) allen bolts that are
furnished. Install the large cam gear on the cam hub at this time using two or seven bolts. Any
bolt location is o.k. Install the crankshaft gear.
Install the complete front cover assembly over hex on the cam hub. (On superstock
models), just position the main cover in place and install the cover bolts, but do not tighten.
Start all the cover bolts. USE NEWSPAPER TO ESTABLISH THE PROPER CLEARENCE
BETWEEN ALL THREE GEARS. A single long strip of newspaper will work best. Be sure it
is placed between idler gear and crank gear as well as the idler to the cam gear. Apply pressure
to the idler side of the timing cover to hold the clearence tight. With the newspaper between the
gears, tighten all the cover bolts. The center removable cover plate can be removed at this point.
Rotate the gear drive to remove the newspaer, then check for smooth rotation.
MAKE SURE YOU HAVE DONE THE ABOVE INSTRUCTION CORRECTLY BEFORE
YOU CONTINUE!
At this point, drill and ream the block through the front covers drill bushings. The
hardened drill bushings stay in the cover permanently. Remove the cover assembly from the
block. Then install the 5/16 dowel pins into the block, with the larger end in the block. With
this assembly completed, your gear drive can be reemoved and reinstalled without additional
adjustment. The lash will always be the same. Cam timing may now be set.
NOTE: Unblown and Supercharged gear drives include a silver laminated shim washer that may
be peeled apart in .003 increments to set cam thrust clearance. This shim goes on the cam hub
between the secondary cover and the cam hub bearing register. The end play must be .000 to
.005.
Note: 12600, 12700, 12900 due to the many different Harmonic Balancers available on the
market at this time, Milodon has had to modify the lower crankshaft gear on all the big block