Cam degree

[crackedback]

Never used a piston stop to determine TDC. Always as PRH does it. Set dial indicator on piston down in bore and come up at the indicator in both direction, In the middle on the degree wheel is TDC. Asjust/Set the pointer and recheck.

 

[twayne24365]

I have always been fine with The indicator, but I will try the “in the bore” method to double check it, but I was pretty paranoid about it and called Lunati, they said that if everything on my end checks out it’s possible the cam could have been re ground, I did find the timing events were off as well,which is what Lunati also said would happen with a re grind. So if that cam were reground on a 99/100 icl ,retarding it to get back to the 105/106 would probably kill a bunch of low end.so I have another cam to try in it tonight so we will see how that one checks out

 

[rustycowll69]

Never used a piston stop to determine TDC. Always as PRH does it. Set dial indicator on piston down in bore and come up at the indicator in both direction, In the middle on the degree wheel is TDC. Asjust/Set the pointer and recheck.

I've done it both ways, but I prefer the dial indicator/split the difference method, myself. I've been very leery of getting a little too muscular hand-cranking the rotating assembly over and running a piston too hard into the positive stop. I'm pretty sure you can break the end of the stop off if you hit it hard enough, especially on some engines like a BB Mopar.

 

[PRH]

So if that cam were reground on a 99/100 icl ,retarding it to get back to the 105/106 would probably kill a bunch of low end.

I’m not following you here.
If the cam is ground with a 110lsa, and you install it at 106 intake c/l...... it’s 4 deg advanced....... period.
Makes absolutely zero difference where the profile is relative to the keyway, or what you had to do to get it there.
“Advanced” or “retarded” is only relative to the lsa.
If the intake c/l number is lower than the lsa number, the cam is advanced.
If the intake c/l number is higher than the lsa number the cam is retarded.
If the two numbers are the same, the cam is straight up.

For example, if you have a cam with a 108lsa, you line up the dots and it comes in at 114 intake c/l.
It’s 6deg retarded.
You use the 4* advance position on the timing set and recheck it, and it’s now at 110 intake c/l.
In this case, you did advance the cam 4*....... but at 110, it’s still 2* retarded.

You then go to the 6* advance position, recheck...... and you’re now at 108 intake c/l.
You’ve advanced the cam total of 6*....... but it’s now “straight up”.

The position of the cam, in terms of advanced or retarded, is referenced as it relates to the lsa.

In order to avoid confusion when talking about cams being “advanced” or “retarded” it’s best to just use the specific numbers.
What the lsa is, and what the intake c/l is.

As in; “the cam has a lsa of 108 and it’s intalled at 104 intake c/l”.
That would be advanced 4*........ regardless of what you did to get it there.

I just installed a cam in a 360. I started out by lining up the “zero” position on the bottom gear with the dot on the top gear.
It was right where it should be.
112lsa in at 108.
It’s 4* advanced, even though it’s dot to dot.