DEGREEING MY CAM

[MAXAMX]

Hey Guys,
Just got finished degreeing my cam and i am 2 degrees advanced. What is the best way to get that 2 degree back?
With a offset crank key? Or maybe an offset cam key?
Im fairly new to rebuilding engines, the last couple i just lined the keyways and let it go.

[ironman_gq]

I think you can get an adjustable timing gear set.

[AMX69PHATTY]

Advanced 2 degrees CAM or 2 degrees Crank ?
The Cloyes True Roller Timing Chain Set has
3 keyways available, std, + 2 deg, & - 2 deg in Cam degrees.
Crank degree values are double Cam degrees.
Some Camshafts have advance ground into them.
Advanced improves low end, retard improves top end.
Maybe call the cam company and ask'em if that's what's intended.
Not aware of any source for offset AMC Cam keys.
For the Crank, SBC Mr. Gasket offset keys can be used
but then the dampener timing mark will also be off.
The nice ~$120 RollMaster timing chain set has 9 keyways.

[MAXAMX]

I just degreed the intake centerline compared to the cam and had 2 degrees more than the cam card specified. I have the summit double row timing chain with the 4 degrees advance/retard, three keyways. Are you saying the keyways on the crank is half the cam, so that would put me 2 degrees. I will try to mess with it tomorrow night. Would that mean my ballancer would be 2 degrees off TDC?

[AMX69PHATTY]

The crank gear keyways are 4 degrees crank, this moves the cam 2 degrees.
The cam sprocket has twice as many teeth as the crank sprocket.
It takes 2 turns of the crank to turn the cam once.
So 4 degrees crank result in 2 degrees cam.

No, using different crank sprocket keyways you will not change the damper timing mark.

Using Offset Crank KEYS will move the dampener.

I'm just a novice hobbyist. have only done it a couple times,
and know I found it confusing too, since the degree wheel is
mounted to the crank not sure if you'll see 2 or 4 degrees change.

[82Waggy]

When you degree a cam, it is relative to crank degrees.

Normally, you would install a cam "straight up" in accordance with the manufacturers recommended intake lobe centerline angle (the point of crank rotation at which max valve lift is achieved). If straight up was at say 108 degrees of crank rotation, this is where max valve lift would occur. If you advance the cam 4 degrees, then max lift would occur at 104 degrees of crank rotation - in other words, max lift occurs earlier relative to crank rotation.

PAS offers the Mr. Gasket 2 degree offset crank keyway http://performanceamstyle.com/Cart/d...b89e8&divi=amc

Some cam manufacturers grind their cams with built in advance. Sometimes there is as much as 4 degrees, sometimes only one degree to take into account some timing chain stretch.

It is not uncommon for the straight up position to be off from the cam card spec due to machining tolerances in the associated parts - thus, the reason for checking the installed position with a degree wheel.

If you feel the installed position is lacking in bottom end performance, you may want to try a little cam advance. Advancing the cam results in closing the intake valve earlier and helps build cylinder pressure and torque. Advancing a cam may also lower peak power output due to an associated reduction in max rpm. Retarding a cam from the straight up position is usually of no benefit to peak power as it delays the intake valve closing point, and thereby reduces cylinder pressure and power across the rpm range.

Be careful about adding too much advance as it cold cause excessive cylinder pressure that may result in detonation in an engine with a high static compression ratio. You should also check for adequate piston to valve clearance as advancing the cam starts the valve opening cycle sooner - meaning the intake valve is open further when the piston is at TDC.