cam degreeing

[benno440]

Just saw another post regarding cam degreeing and now I am not sure whether I did it right.

* I installed timing sprockets dot to dot.
* put piston stop in and went clockwise then counter clockwise and found I was 1.5 degree off on one side so I corrected this.
* found my true TDC and removed piston stop, then lined up the wheel to show TDC.
* put my dial gauge on #1 intake lifter and went clockwise until found max lift, marked It on wheel.
* went clockwise .100 then backed it up .050 and marked what degrees it came up, then went counterclockwise past "0" all the way to .050 on closing side and marked what degree it came at.
* added my 2 numbers together then divided by 2 to find my LSA, I came in at 106 and my cam card says 108 so I turned cam sprocket and redegreed until I got it as close as I could and came in at 107.75 lsa.

does this sound correct?

 

[Hemi Rebel]

Well, no. Lobe separation angle is the difference in degrees between intake and exhaust lift. That has to do with the placement of the lobe on the camshaft. That number will be the same regardless of how advanced or retarded the cam is.

 

[IQ52]

You're close but no cigar yet. What is the LSA for the cam and what is the ICL according to the cam card. When checking the ICL always turn the engine in a clockwise direction.

 

[benno440]

Oh ffs, engines all back together and i have put it in wrong havent I.
agggrh here is cam card

View attachment 212246

 

[Meep-Meep]

What you described is trying to find the intake lobe center line NOT LSA. In order to centerline the cam you need to do a similar procedure as you used to find TDC. .025" or so before max lift and the same indicator reading past max lift. Then do the math. Trying to zero the indicator exactly at the tip of the lobe will introduce error and that is why you go a little before and a little after. If your error was only 2 deg I'd likely leave it alone.

 

[benno440]

cam card did not come out properly here it is again.
the process i did it, i came in at 107.75, is this too far out? what will happen running it like this? Do i need to be at 104? not 108?



- - - Updated - - -

i am not real savvy with all these numbers is there an easy explanation?

 

[383man]

This may help you some. The cam installed centerline is the max lift of the cyl#1 intake valve measured in crank degrees at the crank. In other words if the cam card says to install the cam with a 106 installed centerline that means the max intake lift will be at 106 crank degrees after top dead center. And always go in the same direction (clockwise) when checking the cam ICL. Since it to hard to go to the max lift and get a good readings since you can move the cam a few degrees at max lift most will take a reading like about .050 before max lift and write down that degree reading and then go to max lift and then to .050 after max lift. Then write that degree number down and add it to the first degree number ( the .050 before number) then divide that number by two and get the true max lift degree and then see where it reads to determine if its on or advanced or retarded so you know which way to move the cam if you have to. Ron
http://www.lunatipower.com/Tech/Cams/CamSpecTerms.aspx

 

[benno440]

thats the way i did it i marked the .50 readings both sides and added together then divided by 2 and i came in at 106, my card says 108 lobe separation, so i adjusted the cam gear until i got it to 107.75. is this wrong should it be installed at 104 centre line? or is 108 lobe sep the number, did i get my numbers mixed up? s**t d**n f**k

 

[Meep-Meep]

Altering the ICL will essentially close the intake valve earlier or later and that will have an effect on cylinder pressure. The proper way to install a cam is to go with the manufacturer ICL number and I'd say keep it within a couple of degrees. If you had a 4 deg error I'd do something about that.

 

[benno440]

so install at 104 centre line not 108 lobe separation

 

[benno440]

All good thanks guys got her degreed in at 104.125 cam card recommends 104

 

[benno440]

just a thought, cam card says intake centre line 104 and if installed at 104 it will be 4 degrees advanced, just want to know that this is the optimum setting to install at is'nt it?

and when first install aligning the 2 sprockets dot to dot, then finding true TDC, the cam sprocket dot is 12 o clock and the crank sprocket dot is also 12 o clock, this is right isnt it?

 

[Cranky]

Forget the dots and forget the LSA. Intake Center Line (ICL) is what you want to use and if you're using a degree wheel, the dots can be thrown away but here's another thing to cornfuse you some more. Once the cam is in, do a compression check and see what your numbers are then advance the cam a few degrees and check the compression again (PSI compression) and see if it increased.....if not, put the cam back where it was. No one ever said that extracting every last drop of power was easy.....but it's really not that hard once you get a hang of it and after doing all of that, you should be a pro.

 

[benno440]

thanks Cranky for confusing me some more haha.
Here is what i did and just want to know if my engine will run okay?

set dot to dot on both sprockets.
put degree wheel on at TDC.
installed piston stop and spun the crank both ways, cam up 21* on one side and 24* on opposite way, i added 2 figures together and divided by 2 the adjusted degree wheel to suit, then double check by spinning crank both ways and they were spot on, removed piston stop and set crank on TDC.
installed dial gauge on #1 intake lifter, spun clockwise until found exact base line on lobe, i zeroed the dial gauge. continued to spin clockwise until got to .050 on dial gauge and came up at 19*, i have a hex adjust sprocket so i advanced it a couple of degrees then rechecked the .50 and came up at 21* ( the cam card says IN OPENS 21*)
and (ex opens 49*) spun around and came up at 47* fairly close. so then i rechecked all degrees by going off the highest point of lift and went down .50 each side of lobe and added to degrees together then divided by 2 and came up with 104.125 * where cam card says 104. so i figure i am pretty damn close.

I dont have a compression tester anymore as my sun destroyed it so i figure i am close enough for the engine to run goo, is this correct?


also want to add for anyone else that will read this, when i reinstalled my fluiddampner harmonic balancer using the bolt on style timing tab with the engie still at true TDC, the zero mark on the timing tab was neally 5 degrees out so i corrected the timing tab.

 

[383man]

just a thought, cam card says intake centre line 104 and if installed at 104 it will be 4 degrees advanced, just want to know that this is the optimum setting to install at is'nt it?

and when first install aligning the 2 sprockets dot to dot, then finding true TDC, the cam sprocket dot is 12 o clock and the crank sprocket dot is also 12 o clock, this is right isnt it?

As Cranky said dont worry about the dots. They are there so you can put the chain on right and be in the ballpark. Then once you get true top dead center and check the cam timing of lets just say my cam called for a 106 installed centerline and it came out reading 109. Then if I want to go with the recomended 106 I need to advance the cam 3 degrees. Now it depends on what kind of setup you have to move the cam. I have used the offset bushings before where you have to drill the cam gear pin hole larger to take the offset bushings to move the cam gear and get it on 106. You dont worry about the dots anymore as they will still look lined up or close as your not moving the cam alot. You can also change the cam timing by moving the crank as I use the crank gear with about 8 different keyways to move the cam/crank timing. I like that setup as I did not have to use the offset bushings and when I used the keyway that was closest my cam came out at 105.5 and thats where I left mine. The dots are still lined up as using the different crank gear keyway actually retards the crank instead of advancing the cam and gave me the same 105.5.
When the cam gear dot is at the top (12 oclock) and the crank gear is at its top (12 oclock) the piston is at TDC on the compression stroke. If you line the dots up with the cam gear at the bottom (6 oclock ) and crank gear at the top (12 oclock) which is like the picture you see in most books and is usually called dot to dot the piston is still at TDC but on the exh stroke.
As for using the 106 or what ever the cam manufactor calls for thats fine for normal contitions. You can advance or retard it from the cam manufactors setting if you like as many racers do as it can raise or lower the cam power band and can give more or less low end or top end. Ron

 

[benno440]

thanks Ron, i am using one of those cloyes Hex adjust timing chains, 6* advanced or retarded, to get the 104 recommended setting i had to advance 4*