Degree a cam

[1976kjell]

The 390 in my 63 Galaxie is from 67. The intake is a CJ-intake from 69. What I wonder is which cam the engine has. I have a deegree kit and the intake is off. How to determine if the cam is a GT-cam, a standard 390-cam or another? 

[cjshaker]

You'll have to map out the entire lobe for one cylinders exhaust and intake, then compare it to Ford's specs. That means you'll also need a good magnetic base and a dial indicator.

Find out the exact opening point, take a degree reading at .006, .010, .020 and .050 of LIFTER rise, then measure total lift. Then find the exact closing point. Once you do both lobes that way, then you can determine your lobe separation angle. That should be enough to figure out if it's a stock Ford grind or some aftermarket.

This link to Lunati should help you out: http://www.lunatipower.com/Tech/Cams/CamSpecTerms.aspx

[1976kjell]

Yes, the kit includes everything needed. Googled and red much about cams before started this thread, including the lunati site, but thanks for the link.

Im new to this stuff so here are some questions:

How to find exact opening point? Take a degree-reading exactly when the lifter begins to rise?

Why take degree-readings at .006, .010, and .020?

I guess finding the lobe separation angle is based on the opening/closing points (The degrees between the
"opening+closing divided with 2" points on the intake and exhaust lobe)

Not any disagrrement from me, just asking

[cjshaker]

Most all modern cam makers use a .002 and .050 measurement for their duration figures, but Ford used a much earlier opening figure back in the day (instead of the .050). I can't remember it right off hand, but I believe it was either .006 or .010. But those measurements I suggested will allow you to compare figures to both Ford and newer grinds.

Yes, opening point is the exact point at which lifter rise occurs.

You don't want to use the division method to determine the center of the lobe. Reason being that the front side of a lobe may differ from the back side. The best way is to find the point of maximum lift, noting the spot on your degree wheel, finding it on the other lobe, then determining the difference in degrees.

Edit to add that it can be a bit tricky to find the EXACT point of maximum lift when you have pistons and rings in the engine. It's not easy sometimes to just nudge the crank 1 or 2 degrees with the drag of the rings. That's why this stuff is probably best done with no rotating assembly other than the crank. But with some patience, it can be done pretty accurately.

[1976kjell]

Gave it a try today. I got these results (approximatly):

Cylinder 1 exhaust valve   

-lobe lift max: 0.253" (110° centerline)
-opening point: 69° BBDC
-closing point : 66° ATDC


Cylinder 1 intake valve

-lobe lift max: 0.246" (112°)
-opening point: 47° BTDC
-closing point : 115° ABDC

These opening/closing point are measured at 0.00 lift so the duration became over 300 degrees. My equipment didnt work 110 % as it should , and there may be some errors