EightBall

ok, so Ive read about it before but still dont quite understand it...can someone explain to me, or direct me to a page that has a comprehensive explanation, what LSA, duration, duration@.050, and valve lift are when talking about camshafts...also, what is one supposed to look for in a performance cylinder head? I see all you guys out there talking about what you have and using the details to make your points etc., but I really want to understand it better so I can take a more active role in both the forums and my own car...thanks a ton

DaleMX

iTrader: (4)

Try this for a start.

http://www.compcams.com/Technical/TimingTutorial/

Dale

EightBall

thanks a lot...this helps clarify some things...

FASTONE

Hey EightBallWS6, good questions ,I'm surprised that you haven't got a response.OK LSA standS for lobe separation angle, sometimes LDA lobe displacement angle both mean the same thing ,that is the difference in crankshaft degrees between the peak lift or center of lobe between the intake and exhaust lobes on the same cylinder.Tighter or lower say 110 is about the least you'd want in a street car and 114 is about the most you would want to run on a performance cam, also fuelinjected cars like a wider LDA then carbureted cars.Adv. duration is usually measured at .006 of lobe lift this is also in crannkshaft degrees if you have say 270 adv. duration that means that the engine turns 270 degrees from the time the cam lifts the lifter .006 and then to max lift then going back down to .006 again.I hope you understand?Duration at .050 is the same thing except its measured at .050 lobe lift instead of at .006 as in Advertised duration,say 224 =engine turns 224 degrees from .050 lobe lift til the time cam goes back down to .050 lobe lift,I guess that you knew the cam turns 1 time to the crankshaft turns 2 times, or crank turns twice as fast as camshaft does.OK now lift, that is the lift of the valve off the seat or distance between the valve and the valveseat this is measured at max lift of the cam.
Now for the head question,you want to match your head choice for the rest of your combination of parts,you want to get the smallest cc ports that flow the most air,small ports mean faster flowing air or velocity that makes an engine responsive and fun to drive. Also you've got to match springs, retainers,etc to match your cam,this all gets complicated but if you ask a lot of questions you can make a good choice.
I hope this helps you some!!I'm sure you get some more replies!!