Comp cams degreeing issue

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matty wardle

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I just installed my new comp cam 285 extreme energy high lift hydraulic in my freshly built 451,here,s the problem the paperwork i got with the cam states that comp grinds these cams with 4 degrees advance for optimum street use,so anyway i line the dots up perfectly inline and centreline it in and it goes in at a 102 degree centreline ,the intake centreline for this cam is 106 as stated on the cam sheet i got from comp,so at 102 with the dots lined up is in 4 degrees advance ,so i reinstall it retarding it 4 degrees on the cam sprocket,recentreline it in and of course it comes in at 106,perfect,so now my centreline is to spec as to the cam card,but i miss out on the 4 degees advance that comp grind into them when the dots are lined up,this is bizarre,do i put it in at 102 degree with 4 degree advance or do i put it in at the correct 106 with 4 degree retard,has anyone else had this dilemma,my motor is a brand new 451 with compression at 10.25 to 1 it,ll have a 4500 converter i dont want it to overheat or ping,i currently have the cam in at 106 centreline,will this be fine,am i going to lose power off the line???????????????????????????????????? Matty!!!!!
 
4° is a lot in terms of cam timing change. If it were me I'd leave it as 102.
 
I think you are missing something here, the advance is a comparison of the cam Lobe Separation Angle and the Installed Centerline. IIRC, that cam is cut on a 110 LSA and has an ICL of 106. Installing at 106 is 4 degrees advanced from the 110 LSA.

DO NOT pay attention to where the timing set says it's installed. The timing sets (not all) are HORRIBLE when it comes to the advance/retard/straight up keyways. I had one that the straight up was 2* retarded, change to the 4 degrees advanced keyway, now it was 8* ahead. Only had a 10* change in it... :(

If you put it in with the straight up dots lined up and it came in at 106, it's correct per the card. I'd leave it there.
 
crackedback said:
I think you are missing something here, the advance is a comparison of the cam Lobe Separation Angle and the Installed Centerline. IIRC, that cam is cut on a 110 LSA and has an ICL of 106. Installing at 106 is 4 degrees advanced from the 110 LSA.

DO NOT pay attention to where the timing set says it's installed. The timing sets (not all) are HORRIBLE when it comes to the advance/retard/straight up keyways. I had one that the straight up was 2* retarded, change to the 4 degrees advanced keyway, now it was 8* ahead. Only had a 10* change in it... :(

If you put it in with the straight up dots lined up and it came in at 106, it's correct per the card. I'd leave it there.
Click to expand...


Listen to this guy.
 
He said dot to dot it went in at 102* and he had to retard it to get 106*.
 
Like I said... DO NOT pay attention to where the timing set says it's installed. Note what the dial indicator and degree wheel tell you, that's the correct way to do it..

If the thing is in at 106 when the timing set says it's 4* retarded... so what. It's in where Comp recommends.
 
crackedback said:
I think you are missing something here, the advance is a comparison of the cam Lobe Separation Angle and the Installed Centerline. IIRC, that cam is cut on a 110 LSA and has an ICL of 106. Installing at 106 is 4 degrees advanced from the 110 LSA.

DO NOT pay attention to where the timing set says it's installed. The timing sets (not all) are HORRIBLE when it comes to the advance/retard/straight up keyways. I had one that the straight up was 2* retarded, change to the 4 degrees advanced keyway, now it was 8* ahead. Only had a 10* change in it... :(

If you put it in with the straight up dots lined up and it came in at 106, it's correct per the card. I'd leave it there.
Click to expand...

I see what you are saying. For some reason the last sentence in your statement above threw me off a little. And I do agree what you are saying about the timing marks, forget them. Go by what the degree wheel indicates.
This statement cleared up a lot for me in cam design:

"I think you are missing something here, the advance is a comparison of the cam Lobe Separation Angle and the Installed Centerline. IIRC, that cam is cut on a 110 LSA and has an ICL of 106. Installing at 106 is 4 degrees advanced from the 110 LSA."
 
duster360 said:
he said dot to dot it went in at 102* and he had to retard it to get 106*.
Click to expand...
yeah this is what had me confused,dot to dot it went in at 102,so i moved the crank keyway sprocket to where it says 4 retard,re deegreeed it in and its now perfect at 106,i now understand that the 4 degree advance is the difference between lobe sep and intake centreline
 
The roller cam (from Comp) in my SC Buick was the same- installing it "Straight up" was actually 4 degrees advanced. Just makes you do simple math if you want to advance or retard it.
 
matty wardle said:
I just installed my new comp cam 285 extreme energy high lift hydraulic in my freshly built 451,here,s the problem the paperwork i got with the cam states that comp grinds these cams with 4 degrees advance for optimum street use,so anyway i line the dots up perfectly inline and centreline it in and it goes in at a 102 degree centreline ,the intake centreline for this cam is 106 as stated on the cam sheet i got from comp,so at 102 with the dots lined up is in 4 degrees advance ,so i reinstall it retarding it 4 degrees on the cam sprocket,recentreline it in and of course it comes in at 106,perfect,so now my centreline is to spec as to the cam card,but i miss out on the 4 degees advance that comp grind into them when the dots are lined up,this is bizarre,do i put it in at 102 degree with 4 degree advance or do i put it in at the correct 106 with 4 degree retard,has anyone else had this dilemma,my motor is a brand new 451 with compression at 10.25 to 1 it,ll have a 4500 converter i dont want it to overheat or ping,i currently have the cam in at 106 centreline,will this be fine,am i going to lose power off the line???????????????????????????????????? Matty!!!!!
Click to expand...
105-107 Icl sounds fine. Dont overthink it. Have fun.
 
Not sure which 284cam your installing but I just installed mine a week ago cam 20-228-4. Straight up for me came out @ 107* so I left it. 1* aint ****.
 
An easy way to tell how much advance you have it to check the ex. centerline in conjunction with the intake centerline. I see too many people not check the ex. centerline and that's a big mistake.

If your cam is cut on a 110lca, and you advance it 4°, then the intake should be at 106 and the ex. should be at 114. Dot to dot is just how you set the timing initially then change from there.
Crackedback know's what he's talking about!
 
I too have ran into timing sets that were all over the place (even name brand sets), that's why I always check them. When Comp calls for it to be installed at 106 ICL it is actually advanced 4* because it's ground on a 110* lobe center.

110*, advance it 4* and it's at 106*
 
crackedback said:
I think you are missing something here, the advance is a comparison of the cam Lobe Separation Angle and the Installed Centerline. IIRC, that cam is cut on a 110 LSA and has an ICL of 106. Installing at 106 is 4 degrees advanced from the 110 LSA.

DO NOT pay attention to where the timing set says it's installed. The timing sets (not all) are HORRIBLE when it comes to the advance/retard/straight up keyways. I had one that the straight up was 2* retarded, change to the 4 degrees advanced keyway, now it was 8* ahead. Only had a 10* change in it... :(

If you put it in with the straight up dots lined up and it came in at 106, it's correct per the card. I'd leave it there.
Click to expand...

Hey I understood what you were saying. I guess us Ratards tink alik.
 
my eddy timing chain dot was off a bit,good to have a piston stop....
 
Seems simple enough to me.This guy ,did good.How many times in your past,you didn't degree.And regretted it? Three,to me so far.
 
Abodybomber said:
Seems simple enough to me.This guy ,did good.How many times in your past,you didn't degree.And regretted it? Three,to me so far.
Click to expand...
lol for me every engine ihave built that i used mechanical lifters i degree.and i've built countless hydro equipped engines...about ten mechanical cam engines....:dontknow:
 
Mopar small blocks,hard on timing chains.Had broken in 2 cams,one solid,one huge hyraulic. The o.p intermediate shaft snapped. Shut it off,tore it apart.3/4 inch slack,on the Eddy chain. First time seeing that. Usually ,Eddy's spot on.
 
Cams can have the keyway off also. That's why you should check them when installing in an engine. Then you have a good known baseline to start tuning.
 
matty wardle said:
yeah this is what had me confused,dot to dot it went in at 102,so i moved the crank keyway sprocket to where it says 4 retard,re deegreeed it in and its now perfect at 106,i now understand that the 4 degree advance is the difference between lobe sep and intake centreline
Click to expand...

It is confusing.
But dont forget, if you are using a Rollmaster set (I guess others are similar), when you use the "Advance or retard" 4/6/8 degree keyways...this is CRANK degrees not cam degrees.....so 4 degree on the crank gear is only 2 degrees at the cam (1/2 speed).
So I wonder about your above statement, just moving the crank gear 4 degrees, will only move the cam 2 degrees........ so how did you get 4 degree movement?

Are we confused yet?.....I am.....
Can the experts explain..
Do people use the "Mopar" degree wheel system or a generic wheel system..apparently the Mopar ones are different??
 
There are over 6 datums that can throw things off. Cam key way, cam sprocket key way, crank key way, crank sprocket key way and the aliment marks plus every link in the chain.

My 460 was off several degrees and had to retard it to get it dialed in. It's just the way it goes.
 
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