Just got a custom grind cam from someone off LS1tech. It's from Cam Motion and is a little smaller in certain areas than I wanted, but I got a good deal on it. I have the Cloyes 3145 timing set and was reading up on advancing or retarding the cam since I now have that option. The car is an M6 and one of the things I didn't like about this cam is that it's on a 114. Some friends told me that will raise my shift points slightly, so I was thinking maybe I could use more high end HP. Now I just want to get some ideas of what y'all think about the cam. I looked at the GM 847 specs, and my valves open and close a few degrees before that one does. I've read a little about overlap and valve timing, but I just figured I post the numbers and see if anyone wanted to comment. Also, what do y'all think about how I should install the crank sprocket, advanced, retarded, or straight up? Thanks.

SPECS:

Duration at .050 - 225.8/230.9
LSA - 113.8
valve overlap = .5 crank deg
INTAKE
valve open = 3.1 BTDC
valve closes = 42.8 ABDC
valve lift = .55924"
*centerline = 109.8 ATDC
EXHAUST
valve open = 53.4 BBDC
valve closes = -2.5 ATDC
valve lift = .56857
*centerline = 117.8 BTDC

And in the middle of the page it says "INSTALL CAM ON ** below". Could this be referring to the lobe centerlines?

 

It already has a 4*advance in it and I wouldn't go dicking around with it without calling Cam Motion and talking to Terry. He can tell ya where to put it OR weather to leave it alone. The 4* advanced will give ya a bit more low end torque. Dot to Dot IS the correct place and that has the 4* in it already.

It really sounds like ya need another cam (larger) to do what ya want to do.

 

1racerdude is correct but Terry doesn't work for Cam moition anymore. Most cars like the cam being advanced b/c it gives more torque at a lower RPM. That help acceleration which gets trhe car going quicker. I have advanced some cams a couple degrees and it always helped. I would check with cam motion first. Later Clint

 

OOPs.

 

To me, cams are like people...straight up ones are always better than retards.


P

 

Good point P but advanced people are even smarter than straight up huh? LOL

 

Thanks Clint and 1racerdude. I do want a larger cam, but I got this one for such a good deal, it was close enough. I'll install it straight up, but how can you tell it has 4 degrees advance in it? Thanks.

 

I did the math. The numbers are on the card. 113.8-109.8-117.8.

 

That equals -113??? I can see that the difference between them is 4, but how do you know it's advance and not retard?

 

Advance = LSA - ICL. If it was retarted then the ICL would be greater that the LSA.

 

Thanks. Anyone have any idea about what the curve will look like on this thing with full bolt ons and shorties with stock heads, 1.6 RR and ewp?

 

 

so the LSA for this cam is more accurately described as 113.8+4 ?

 

That's not correct.It is ground on a 113.8LSA and installed on a 109.8ICL. The + sign means it is advanced,a - sign means it is retarded. That makes it a 109.8 ICL with a 113.8LSA as your cam card states even though ya have to subtract from the 113.8LSA to get a 109.8ICL and add to the 109.8ICL to get the 113.8LSA.The exhaust figures the same as the intake and ya add the 4* to make it a 117.8ECL. The 113.8LSA is right in the middle.

See if ya can find a picture of a degree wheel on line and look at the numbers and read it like a watch,then maybe ya will get it set in your mind. Kinda hard to visualize the way a cam is set up until ya get the picture in your mind.

Have I Confused ya enough yet?

 

Probably not confused enough yet. Sorry for all the questions, just trying to learn more about my car and cams in general. I'll try to check one of those degree wheels out.