Boosted Apex

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DIY: Degree Your Cam

YOU MUST ALWAYS FOLLOW THE INSTRUCTIONS AND SPECS OF THE CAM'S DESIGNER, THERE USUALLY IS A CAM CARD WITH ALL OF THE TIMING SPECS FOR THE CAM. FOLLOW THOSE SPECS EXACTLY.

You need:
Cam card or cam specs IE Centerline, or X lift at X duration.

Degree wheel, the bigger the wheel the better.

(1) Dial indicator w/ Stand its good to find one that reads at least 1/2″ (.500″) of travel and has increments every 1 thousands of a inch.

(2) Degree Wheel

If dual cam you need 2 indicators and stands.
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Set up motor with tools listed above.

I remove the one valve cover stud, bolt down that exhaust flange, you need something very solid and metal for the magnetic of the stand to grab.newhead016.jpg

Make sure the dial is pointed on the same axis as the valve, and make sure you have a good surface for the point to ride on, you dont want it slipping off the retainer or into the keeper cup.
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First: Find true TDC using a dial indicator on the piston. On a short rod motor there will be very little dwell, long rod motor you will need to use a piston stop for find true TDC. You want to find the exact moment the piston is at TDC, make a pointer out of thick wire and have it pointing at 0 TDC on the degree wheel.

Measure the valve lift in relation to crank degrees, check your cam card some specs are with zero valve lash. Other with a given valve lash, follow the card.

Find Centerline:

If the card ask you to set the cam at 110 ATDC degree lobe center on the intake lobe means the centerline of the intake lobe needs to be at 110 degrees crank rotation after top dead center. Centerline is not max lift or peak of the lobe, since many cams hold the valve open at a static max lift for many crank degree there is no true “peak.” So many people use the 50k opening method for finding the centerline.

Which means you find the crank degree at .050″ of lift,and 50k from the seat closing.

Write down the degree number for both events.

Take those 2 numbers add them together, then add 180.

Then divide by 2, then minus the opening number.

Equals centerline.

Adjust cam gear to get the proper center line.

Double check.

The second way you can degree a cam is if the cam car gives you a X lift @ X degrees.

Hypothetically if my cam card said 50k of valve lift at 25 degrees BTDC it means the cam needs to be opening the valve .050″ at 25 degrees before TDC.

Rotate the engine in the proper direction until the valve has moved .050 off the seat. Check your degree wheel, if the degree isnt 25 BTDC loosen up the cam gear and rotate crank to 25.

Double check.

Zero on a cam gear means nothing, sometimes to get the cam in proper timing you have goofy cam gear setting due to whole host of factors.

Degreeing the cam puts the cam in the exact spot where it needs to be for power and clearances.

Hope this helps.

Dual Cam Video Tutorial

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