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Degreeing a cam

Mark Barnes

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I admit I have never degreed in a cam. 40 yrs. ago when I was fooling around with motors it was never an option, just line up the dots and lock it down.
My new cam card says "4 degrees of advance have been ground into this camshaft".
1. Will it be necessary to add advance when installing?
2. Will there be any benefit to doing so, or should I install it "straight up?"
Any light you can shed on this would be appreciated. I realize this is a broad question, and if further info is required, I'd be glad to fill in the blanks. Thanks.
20210221_184539.jpg
 
I would try and get the intake where the cam card says.
To do that you need to define exactly where tdc is and get a degree wheel and set up a method to measure the intake lobe.
You can do some research at comp cams and others. Get a good book as well.
It's worth the effort. You can't just trust that your TDC mark on your balancer and timing set are accurate to within a degree.
We put a cam in my son's 5.9 and I couldn't believe how far off the intake centerline was off.
6 degrees retarded measured it 3 times just to be sure.
Had to get another timing set with a few positions to get it where we wanted it.
Are you sure you won't have piston to valve clearance issues?
 
You will want to install it at the recommended 108 degrees lobe center method. The magic is already there doing it this way.
 
I would try and get the intake where the cam card says.
To do that you need to define exactly where tdc is and get a degree wheel and set up a method to measure the intake lobe.
You can do some research at comp cams and others. Get a good book as well.
It's worth the effort. You can't just trust that your TDC mark on your balancer and timing set are accurate to within a degree.
We put a cam in my son's 5.9 and I couldn't believe how far off the intake centerline was off.
6 degrees retarded measured it 3 times just to be sure.
Had to get another timing set with a few positions to get it where we wanted it.
Are you sure you won't have piston to valve clearance issues?

Almost absolutely sure I will...probably need pistons eyebrowed. Don't have the motor together yet though.
 
I would go with the 108 ICL and see how she runs. Course you need to find the perfect TDC to use. Myself I like to do the max lift intake lobe centerline method (yours calls for 108) and then after its set at 108 I then check all the cam specs for valve openings and closing to be sure the cam was ground right.
 
Sounds like you’re asking for the technical “how” more than the “where”. You’ll need: magnet mount dial indicator, degree wheel, piston stop. Can do it without the degree wheel and use a tape measure but you’ll need to be comfortable with basic math and not lose track.

First, using the piston stop in place of the #1 spark plug hand crank the engine (battery disconnected) clockwise until the piston hits the stop. Mark the harmonic balancer where the timing cover TDC mark is. Do the same counter clockwise. The timing mark should be right between the two. If it isn’t you’ll need to either get a new balancer or make a new mark for TDC.

Anyway, pull out the stop and put the engine at TDC. Set up the degree wheel so your wire (indicator) points at 0 degrees.

Now pop off the distributor cap and turn the engine so that the rotor is pointing toward #6. This is #1 180 degrees out.

Remove the driver’s side valve cover and set up your dial indicator so it’s on something that moves on the intake rocker. I like the dimple where the pushrod goes but you can use the valve retainer too. People will tell you at this point that it’s gotta be the lifter itself. Not for this. Crank the engine until the intake valve is at max lift. Now sit and watch it. You need to be sure the lifter is done collapsing before you do more. A moving target won’t work.

Set the indicator to 0.000”. Back the engine up counterclockwise until the indicator shows around .060 or so. Go clockwise again until it’s at exactly .050”. Don’t back up. Take the degree wheel reading. Turn further clockwise past max lift and back down to .050”, once again, don’t back up. Take the degree wheel reading **from TDC** some degree wheels go back down at 180, make sure you keep counting up.

Average the two numbers (angle 1 + angle 2)/2. That’s your cam centerline.
 
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