What is the point of Advancing/Retarding Cam?

[CobraSix]

I just got my double roller timing set. It is really nice. When I got it I started wondering why would you want to advance or retard the cam? Is this different from timing. In my mind I'm thinking yes...but can't put a reason to it or think of they you might want to. Thanks for any help.

Slade

 

[CobraSix]

Okay...after thinking about it...I know what it does...it will change when the intake and exhaust open and close in relation to the cylinder position...but what is more advantagous to advance or retard the cam or leave it at 0? Thanks.

Slade

 

[Thad]

Sorry you missed it, there was a long thread on this just before the "CRASH". Will try to keep it simple.

Degreeing a cam is to make sure it it is installed at the designed position.

Then there is degreeing a cam to a position different than design position for performance.

Basically what happens is the cam's HP and torque characteristics are move up or down the RPM "scale". It changes nothing about the cam it self as ground, but there can be some power increase or advantage if cam characteristic are moved to a point where more effective.

Advancing the cam moves events down scale to a lower rpm, making it happen earlier in relation to the designed cam position

Retarding moves up "scale" to a higher rpm, making it happen later.

Degreeing a cam to a position other than design is a mostly race tuning tool to help match HP/ torque to gears or intake /header efficiency. For street it help put the torque at the best RPM range for gears used.

 

[StrangeRanger]

FWIW, on a Ford Kent 1.6 adding 4* of retard moves the engine's power band up about 1000-1500 RPM.

Also many late model engines have retarded cams for emissions reasons, so NEVER assume that the factory cam is "straight up" frequently it is not.

 

[rbohm]

8) to look at it from a racers point of view, you want to retard the cam when you have slick track conditions as it delays the point when the power comes on hard and usually prevents wheelspin, especially coming off the starting line. cars that are underpowered can take adavntage of the low end power gain advancing the cam gives you. also if you have good traction you want to advance the cam to get the power down sooner.

 

[Anonymous]

so then what would be a safe advance on the cam? 4* maybe?
-Chris

 

[Anonymous]

the main idea,on street engines,regarding advance and retard options is to install the cam according to the grinders specs.the problem is that machining and inaccurate parts tend to through the cam timing out.an example of this is when i purchaced a good brand of roller timig set,for my hemi 6 and wondered why i couldn'tset the cam up properly,at 0*,and found the timig marks were half a tooth out!but using the optional timing keyways we installed the cam at 6* retard to get the desired timing.with my present geardrive,ihad to install it at 2* adv to get the required result.read somewhere,long ago,monkeys aline dots,engine builders use dial indicators!! :roll: