To advance or Not
- Thread starter RAT ROD AL
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I put rings and bearings, oil pump along with a tc and gears and a bit of a cam. Couldn’t believe the difference. All around better car with pretty decent power and mileage. Kim
Ok enough talk about ford stuff. Lol. Let's get back to degreeing this cam. I found my cam card. And I mooched my neighbor's degree wheel. My plan is to use the Intake Centerline Method. According to the cam card, am I to check for a 102.0 install?
I do have a dial indicator also.
yellow rose
Overnight Sensation
When then you are golden. If the cam card calls for 102 that's where I'd start.
If you go to mgispeedware.com you can input all the data from you cam card and see graphically what your lobes look like.
The process is relatively simple. Find absolute TDC and set the degree wheel to TDC. Drop a lifter onto intake number 1 cylinder and I use a pushrod or something similar to that so you can set the dial indicator up in line with it.
Next, turn the engine over until the dial indicator reads zero. I never turn the engine backwards to degree the cam.
Look at your cam card. It will tell you lobe lift. What ever that number is, take atleast .050 off of it. For example, if the lobe lift is .380 use .350. Any number .050 or greater works.
Now that you are at zero on the base circle, and we have our fictitious number of .350, roll the crank until the indicator reads exactly .350 and read the degree wheel. Keep turning the crank in the correct direction of rotation and watch the dial indicator move to max lift (theoretically it should be .380) and then it will start back down towards zero. When it is at .350 exactly read the degree wheel again. add the two numbers together and divide by two and that is your intake centerline. If it's 102, you are in the tall cotton. If it's not, you need to correct it. 1 or 2 degrees off doesn't bother me, but it should be within a degree. At 102 if it came in at 101 I'd move it back to 103 and leave it there.
If you go to mgispeedware.com you can input all the data from you cam card and see graphically what your lobes look like.
The process is relatively simple. Find absolute TDC and set the degree wheel to TDC. Drop a lifter onto intake number 1 cylinder and I use a pushrod or something similar to that so you can set the dial indicator up in line with it.
Next, turn the engine over until the dial indicator reads zero. I never turn the engine backwards to degree the cam.
Look at your cam card. It will tell you lobe lift. What ever that number is, take atleast .050 off of it. For example, if the lobe lift is .380 use .350. Any number .050 or greater works.
Now that you are at zero on the base circle, and we have our fictitious number of .350, roll the crank until the indicator reads exactly .350 and read the degree wheel. Keep turning the crank in the correct direction of rotation and watch the dial indicator move to max lift (theoretically it should be .380) and then it will start back down towards zero. When it is at .350 exactly read the degree wheel again. add the two numbers together and divide by two and that is your intake centerline. If it's 102, you are in the tall cotton. If it's not, you need to correct it. 1 or 2 degrees off doesn't bother me, but it should be within a degree. At 102 if it came in at 101 I'd move it back to 103 and leave it there.
Ok heres my card. Forgot to post it up earlier.
Wyrmrider
Well-Known Member
You will end up retarded on an asymetrical cam, that's one reason guys advance them more than the cam card says
If you have the .050 timing adjust the cam so the cam timing is correct at .050 lobe lift
but here comp gives .006 timing at which the cam can turn lots of degrees to move from .004 to .006 to .0088
so maybe comp wants you to us YR's method- which also works on symetrical lobes
The fact that they are giving you a 102 Intake Centerline is a clue that it is an asymetrical lobe and 102 is not half the distance between intake open 36 intake close 63 which looks like 103.5
Which thumper is that?- does not look like one for stock low compression where you see cams with intake close in the 54 area
What I'm trying to say is that you do not want to use YR's method unless the grinder wants you to-- and vice versa
If you have the .050 timing adjust the cam so the cam timing is correct at .050 lobe lift
but here comp gives .006 timing at which the cam can turn lots of degrees to move from .004 to .006 to .0088
so maybe comp wants you to us YR's method- which also works on symetrical lobes
The fact that they are giving you a 102 Intake Centerline is a clue that it is an asymetrical lobe and 102 is not half the distance between intake open 36 intake close 63 which looks like 103.5
Which thumper is that?- does not look like one for stock low compression where you see cams with intake close in the 54 area
What I'm trying to say is that you do not want to use YR's method unless the grinder wants you to-- and vice versa
yellow rose
Overnight Sensation
I just ran the numbers.
If he uses my method and goes in 5 ahead, it looks like every other Comp grind.
If he uses my method and goes in 3 ahead, the overlap triangle will be centered.
Either way, I never care where the cam is at at .050 lift unless the lifter bores have been corrected and you use roller cam bearings.
Even Billy Godbold uses the intake center line method because he says it matters more where the piston is at max lift rather than where the piston is at .050 lifter rise. Or .006 lift.
If you want to see what he says about all of this, the article is in the March 2020 edition of Hot Rod magazine.
If he uses my method and goes in 5 ahead, it looks like every other Comp grind.
If he uses my method and goes in 3 ahead, the overlap triangle will be centered.
Either way, I never care where the cam is at at .050 lift unless the lifter bores have been corrected and you use roller cam bearings.
Even Billy Godbold uses the intake center line method because he says it matters more where the piston is at max lift rather than where the piston is at .050 lifter rise. Or .006 lift.
If you want to see what he says about all of this, the article is in the March 2020 edition of Hot Rod magazine.
yellow rose
Overnight Sensation
turboking15
Well-Known Member
I see that cam calc software is working out well for ya!!
yellow rose
Overnight Sensation
Did you post that??? I use that all the time. Looking at lobes graphically changes what you think about any cam. Even looking at the above lobes you can see the intake and exhaust lobes are substantially different, even though they are numerically fairly close.
I couldn't remember who posted that but yeah, I use it all the time.
THANK YOU!!
turboking15
Well-Known Member
Yeah, it definitely makes comparing cams alot easier and seeing what effects moving the centerline around will do. ive been using it to learn about what makes a "turbo cam" a turbo cam. great tool!
you gonna just leave us hangin LOL what's the verdict?
one other note, myself and YR found - the issue of Hotrod magazine is actually the April 2020 not the March. It is a good read
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