skidmarkracing

ok guys here is the text version of the how-to

How to Degree a Cam Shaft:

There are several ways to degree a cam shaft. This is the way that I have always done it, some may agree or disagree on the process. For that I say "To each his own". The basics of degreeing a cam shaft are to find the centerline of each cam.

To start you will need tools: everyone loves tools
1. dial indicator w/ magnetic base
2. dial indicator extension
3. degree wheel (summit has a whole kit pretty cheap)
4. pointer for degree wheel (comes with summit kit)
5. 18mm socket to spin the crank shaft
6. pair of solid lifters, the existing ones can be used if they do not bleed pressure during this process. You will know if they are bleeding if the measurements keep changing.

Engine prep:
1. remove spark plugs
2. remove valve covers
3. remove front cover from motor, to some removing the front cover may seem excessive, but it makes the process alot easier.

Degree process:
I check the cam events on cylinder 1 and 6. You can use any or all cylinders, but I use these two since they are on opposite banks and are opposite of each other in firing order.

****always perform the action spinning the motor clockwise, never counter clockwise. If you miss an event, then spin the motor all the way through clockwise to get back to that event. never rock back and forth.

First you will need to find TDC (Top Dead Center) of the cylinder you are checking. Use the dial indicator to watch the piston travel. This is where you will use the extension. Now at the top of the stroke there is dwell period. This is where the piston stays at the same location while the crank is still spinning. The way to test for TDC is to measure this dwell area. Watch the dial indicator and measure the piston at a set distance on the compression and the power stroke and then take the average of the two readings. I check the events at .050 on the way up and on the way down. Average the two and you have top dead center. Basically watch the dial as the piston is coming up. when it hits .050 from 0, write down what your degree wheel says. Then watch the indicator as the piston is on its way down, when it hits .050 from 0 write down what your degree wheel says. Split the difference and you have TDC.

Once you have TDC adjust the degree wheel and pointer so that they read 0. Set the dial indicator up on the rocker parallel to the valve. it is important you have the indicator set so that it is the same angle as the valve and as close to the center of the valve stem as possible.

Rotate the engine until you find max lift on the lobe you are checking. Set the dial indicator to 0. Ramp rates on the lobe are not the same on the ascent as the descent, so you will want to take an average. Much like you did for TDC to find the center line. Again use the .050. Take degree wheel reading at max lift minus .050 and again at max lift plus .050. The average is your centerline.

If you centerline is off, then adjust the cam accordingly. You will want your centerline to be at 0. Plus or minus 1 or 2 degrees is fine.

__________________
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Brahmus

Good stuff.

I have also heard advancing them or retarding them gives different effects to the power curve. How does that work? Or is 0 best?

skidmarkracing

Yes by doing advance or retard you can adjust your power curve. Depending on what you want to achieve.

l8tapex

bump
Thanks for your reply Skidmark!