Milodon Cam Gear Drive

[Garys1969RR]

Took this 496 apart, and it has a Milodon 13000 gear drive turning a Comp Cams solid roller. So when I put this on the 512 I'm building, I will need to degree in the cam. Instructions are pretty straight forward, but how do you degree it in with the heads on, and valve train on, since it doesn't have timing marks to get it close first? If I put in 1 set of push rods for #1, the cam will prob turn from spring pressure. So do you put the dial indicator on the lifter, and for .050 valve lift, that would be .034 at the lifter. Wish they had put timing marks on the gears, just to get it close first. Has anyone done this before? Thanks.

 

[451Mopar]

Remove the rocker arms so valves won't hit pistons when setting up the timing.
Use a piston stop that screws in through the spark plug hole, and find TDC, where degree wheel reads the same degrees before and after TDC when the piston reaches the stop. With the degree wheel reading correctly, remove piston stop, and rotate the crank to the desired iCL Installed Centerline.
With the cam disengaged from the crank, use a dial indicator on the #1 Intake pushrod (or use a real long indicator extension), and find the cams max lobe lift.
That should get the timing close to check. Install the idler to engage the crank and cam gears, then rotate the crank back and then come up to 0.050" before max lobe lift, take degree measurement #1. Rotate past max lob lift to 0.050" after max lobe lift and take degree measurement #2.
Add the #1 and #2 measurements together and divide by 2 to get the actual Intake installed position.
I think you adjust the advance/retard with using offset bushings in the cam gear.

 

[Garys1969RR]

OK thanks! The gear has 7 positions for cam timing. Straight up, 3 advance and 3 retard spots. The Intake valve opens at 34* BTDC @ .050" lift. So can I use the intake opening point for cam timing? Seems that would be an easier way to do it. Thank goodness I have a degree wheel and dial indicator. I can do all this before installing the heads. Will just need to put the dial indicator on the lifter, and raise it .034". That would be .050 at valve with a 1.5 rocker arm ratio. Is this method as accurate as the ICL method?

 

[steve340]

You need to piston stop it like 451Mopar said to find true TDC or you can be out a little due to the dwell of the piston at TDC while the rod rolls over the top.
All 0.050 figures are at the lobe.

 

[Garys1969RR]

You need to piston stop it like 451Mopar said to find true TDC or you can be out a little due to the dwell of the piston at TDC while the rod rolls over the top.
All 0.050 figures are at the lobe.

OK, I'll do that. Heads will be off, so I can either make a positive piston stop for it, or use a dial indicator to measure piston height before and after TDC, making sure it is the same degrees either side of TDC.

 

[steve340]

Just use a piece of flat bar with a couple of holes in it and short bolts in to 2 headstud threads. With a nut under it. So long as the crank stops in the same place before and after TDC. The middle of that will be true crankshaft TDC. Make sure to use number 1 cylinder.

 

[451Mopar]

If using the open/closing points, they are the 0.050" lobe lift at the cam.
I start by installing the cam using the Intake Centerline method, then verify the open/close points.