Degree the Cam

cat-vi

cat-vi

Ty Wannabe
I've just installed the camshaft, read carefully the instruction and so on, all parts from compcams, cam, timing set, lifters, pushrod, and rockers to control the valves in vortec heads, in instruction manual it is stated the importance of degreeing the cam, ok, so I bought a degree wheel and indicator clock, but with the double chain timing gear from compcams, (this is the timing gear offered by RPM), it seems like I'm not able to adjust the timing anyway, so what is the deal here? Do I got the wrong timing gear or should I check the timing of the cam just to find out that it is OK?
 
Couger1968

Couger1968

Dazed and Confused
Re: Degree the Cam

I have wondered the same thing. From what I have read it is just to check and make sure the specs are right. You adjust the cam by drilling the index pin hole in the cam gear and utilizing off-set bushings to adjust it. Here are the bushings: http://www.summitracing.com/parts/CCA-4760/
 
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Icarus-54

Icarus-54

Donating Old Member
Re: Degree the Cam

If your cam is off you can drill out the holes and install a set of offset bushings or buy an adjustable timing sprocket,via Cloyes,Crane,ect.Some turbo people intentionally retard the cam timing to make the cam work better with the stroke of the motor.See John Gerber's post on cam timing.
 
Osmosis

Osmosis

New member
Re: Degree the Cam

You may want to check with the supplier who made your cam. Many times they will factor in 2 or 4 deg advance into the spec's of the cam. Not always, but some companies do, my last cam I requested it to be 4 deg advanced so I would not have to insert the bushings.
 
M

MoJo

New member
Re: Degree the Cam

Comp Cams grinds their cams 4 degrees advanced to compensate for timing chain wear.

Most high performance timing sets have three key-ways in the crank sprocket for adjustment.. You can use those key-ways to install the timing set 4 deg. advanced, 4 deg. retarded or normal. For example, Cloyes 9-3145, double roller timing set for SB Chevrolet V6/V8 roller cam engines.(4.3L V6 engine without balance shaft.) That information is in the installation instructions.
 
cat-vi

cat-vi

Ty Wannabe
Re: Degree the Cam

Ok, Thanks folks, so compcams expect their timing chain to stretch as much as 4 dgr. I find that quite unlikely. Yes the sprocket at the crankshaft got three key-ways, but this will move it much more than 4 dgr.?
Then there is the drilling and inserting of a offset bushing, well, I have to take a closer look into this.
 
Osmosis

Osmosis

New member
Re: Degree the Cam

From what I remember, Comp Cams did this as their standard grind, but you could get a cam set @ zero instead of 4 deg advanced. Its been a long time, but I think you get more power out of the cam when it's a little advanced, or at least it changes your power band.....it's been a long time since I've built an engine.....10 yrs :(
 
M

MoJo

New member
Re: Degree the Cam

The Comp Cams camshaft in my engine was installed according to specifications. The cam card indicate the camshaft intake lobe should be installed at 108 degree LCA at 112 degree LSA.

When the camshaft was installed using a degree wheel at 108 degree LCA, it was checked at 108 degrees LSA which means the camshaft Lobe Separation Angle was ground 4 degrees advanced. The LSA is ground on the camshaft and cannot be changed but it can be moved by advancing or retarding the crank angle. Usually advancing the cam will add a little low end torque with some sacrifice of top end power and less to piston to valve clearance. .

The degree wheel is only used only to check to see how much advance is ground into the camshaft or to check the cam timing if you don't trust your cam grinder. If you have a camshaft that was ground by a reputable cam grinder such as Comp Cams, install the cam with TDC at 0 on the crank sprocket and toss the degree wheel..
 
Windedv6

Windedv6

Ty n 10s
Re: Degree the Cam

MoJo said:
The Comp Cams camshaft in my engine was installed according to specifications. The cam card indicate the camshaft intake lobe should be installed at 108 degree LCA at 112 degree LSA.

When the camshaft was installed using a degree wheel at 108 degree LCA, it was checked at 108 degrees LSA which means the camshaft Lobe Separation Angle was ground 4 degrees advanced. The LSA is ground on the camshaft and cannot be changed but it can be moved by advancing or retarding the crank angle. Usually advancing the cam will add a little low end torque with some sacrifice of top end power and less to piston to valve clearance. .

The degree wheel is only used only to check to see how much advance is ground into the camshaft or to check the cam timing if you don't trust your cam grinder. If you have a camshaft that was ground by a reputable cam grinder such as Comp Cams, install the cam with TDC at 0 on the crank sprocket and toss the degree wheel..
Click to expand...

^^^ what he said^^^ Unless you are doing some serious racing and have a need to play around with advancing/retarding the cam put the cam in straight up as MoJo said.

FWIW the sprocket you have with the different keyway in it does give you some advance/retard options. Just because there are clocked at large spacings you are only going to be a couple degrees of change. You have to use the correct markings for the different keyway mounts. Check the instructions.

John
 
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