GMC Truck Forum banner

1 - 8 of 8 Posts

·
GMFS slowest truck :read:
Joined
·
5,501 Posts
Discussion Starter #1
What the hell do all the numbers mean for cams??? Im just trying to figure what cam to get without havin to ask everyone what the advantages of a list of cams. thanks.
 

·
heavy on the skinny pedal
Joined
·
1,732 Posts
lift equels how far the valves are opend in thousandths of an inch

duration is how long the valve stays open such as if the cam has 212 degres of deration the valve will be open 212 degrees of the possible 360

valve overlap is how many degrees of rotation both valves are open on the 360 degree rotation.
 

·
HOT AIR BALLOON OWNER
Joined
·
14,932 Posts
Don't forget you have two reading of duration... adv and @ .050.

The Adv will help decide on how well the cam idles and what sort of power it will make.

 

·
Broke
Joined
·
350 Posts
The LSA will play a big role in idle quality. The lower the LSA the lower the idle quality (which can be a cool thing eheh).
 

·
HOT AIR BALLOON OWNER
Joined
·
14,932 Posts
LSA isn't only about idle, it also helps with idle vac too as well as midrange punch. Tighter LSA's also make the powerband less "peaky" AND a tight LSA isn't good for FI/Nitrous as you could actually blow it out the exhaust...

I've seen quite a few 204/211 .460/.480 110LSA cam's that idle fine...the seat-to-seat duration or advertised plays a large role also. It deals with the ramp rates of the lobes at .006" lift. Lower Adv is a faster lobe making a cleaner idle.
 

·
geauxlow
Joined
·
3 Posts
black4x4 said:
lift equels how far the valves are opend in thousandths of an inch

duration is how long the valve stays open such as if the cam has 212 degres of deration the valve will be open 212 degrees of the possible 360

valve overlap is how many degrees of rotation both valves are open on the 360 degree rotation.
I believe every time the crank rotates the cam rotates twice. So there should be a total of 720 degrees on a cam. Does this make any sense? :think:
 

·
Broke
Joined
·
350 Posts
Hit Man X said:
LSA isn't only about idle, it also helps with idle vac too as well as midrange punch. Tighter LSA's also make the powerband less "peaky" AND a tight LSA isn't good for FI/Nitrous as you could actually blow it out the exhaust...

I've seen quite a few 204/211 .460/.480 110LSA cam's that idle fine...the seat-to-seat duration or advertised plays a large role also. It deals with the ramp rates of the lobes at .006" lift. Lower Adv is a faster lobe making a cleaner idle.
:word:
geauxlow said:
I believe every time the crank rotates the cam rotates twice. So there should be a total of 720 degrees on a cam. Does this make any sense? :think:
I think the crankshaft spins one time for every half turn, but im not sure its been a while lol...
 
1 - 8 of 8 Posts
Top