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  • 1 Post By Henry Rifle
  • 3 Post By techinspector1

Thread: Degreeing a Cam-Step 1-Do I have this right?

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  1. #1
    Rdobbs1977's Avatar
    Rdobbs1977 is offline CHR Member Visit my Photo Gallery
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    Jan 2016
    Car Year, Make, Model: 1972 Z28 Camaro Drag Car,2500lbs w/motor

    Degreeing a Cam-Step 1-Do I have this right?


    At some point I'd like to degree my cam for the first time with the heads off. Wanted feedback from forum members if this sounds right on finding true TDC as a first step:

    1. With degree wheel on and loose and with a pointer in place, move #1 piston close to TDC, set the wheel so that TDC or '0' aligns with pointer, and tighten wheel down.

    2. With stop plate over the cylinder, rotate crank clockwise until it stops against the plate and write down the degree shown. Rotate crank counterclockwise until it stops against the plate and write down the degree shown. Add the two together and divide by 2. This should give me the true point of TDC.

    3. Adjust my pointer so it points to this measurement. Loosen wheel and move it to where my pointer is now. Now rotate crank clockwise until it hit plate and observe the degree measurement, rotate crank counterclockwise and observe degree measurement. If both measurements are the same then I know my pointer is positioned right for true TDC.

  2. #2
    Henry Rifle's Avatar
    Henry Rifle is offline CHR Member Visit my Photo Gallery
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    Apr 2004
    Little Elm
    Car Year, Make, Model: 34 Ford Low Boy w/ZZ430 Clone

    You don't need any help. You've got it right.
    techinspector1 likes this.

    Gone to Texas

  3. #3
    techinspector1's Avatar
    techinspector1 is offline CHR Member Visit my Photo Gallery
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    May 2003
    Zephyrhills, Florida, USA
    Car Year, Make, Model: '32 Henway

    In order to keep the degree wheel from slipping, install a harmonic damper onto the crank with its key, then use the 3 bolts to secure the degree wheel to the damper hub. I used to keep an old damper in the garage that I had honed out with a dingleberry brake cylinder hone....
    Brush Research BC Flex-Hone Tools BC14M18 - Free Shipping on Orders Over $99 at Summit Racing
    .....so that it was just a slip fit onto the crank snout to do this operation, like shown on the video below. You will want at least an 11" diameter degree wheel so you can easily read the numbers. It doesn't matter if the inertia ring has slipped in relation to the damper hub, you will not be referencing the inertia ring for anything, just using the three bolt holes in the damper hub to secure the degree wheel. You could even cut the inertia ring off the damper if you wanted to and remove the elastomeric material. That would certainly keep anyone from trying to use it as a damper ever again, because a damper has to be a press fit on the crank snout to transfer harmonics to the inertia ring properly.

    As far as the solid lifters required for this operation, I have purchased genuine solids for the motor I was working on and also have modified hydraulic lifters for the purpose of degreeing the cam. You can take 'em apart and fill 'em with flat washers like the stock and super stock class drag racers do or you can fill the lifter body with JB Weld, re-install the pushrod cup and let the epoxy set up. JB Weld is available at any auto parts store and McMaster-Carr has washers that will work.....

    You mentioned in your PM to me that someone told you claying the pistons is old school and that you should use a dial indicator with lightweight checking springs. I would answer that you can do it either way, whichever one blows your skirt up. Matter of fact, if you're not in a hurry, do it both ways and add the info to your repertoire of how to do things. As far as cost between the two methods, oil-based modeling clay from the craft store will be a couple of bucks. Checking springs, dial indicator and magnetic base will be a little more money.

    Use a bolt to secure the harmonic damper that will use all available threads in the crank snout and torque to spec. Matter of fact, I used to use a bottoming tap to finish out the threads in the snout when I was building a motor, then use a little longer bolt to secure the damper hub. Install a flexplate on the rear of the crank so you can hold the teeth with a large flat blade screwdriver against the engine stand to keep the crank from turning while you torque the bolt. With the bolt tight, you will be able to turn the crank counter-clockwise with your ratchet without backing out the bolt.

    Last edited by techinspector1; 03-08-2016 at 02:23 AM.
    NTFDAY, Rrumbler and glennsexton like this.

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