So, I've had a few questions and thought I could shed some light for newbies and create something to talk about for the experienced.
Cam 101
Specs are measured at .040' / 1mm valve lift. (this will take out any lash and dictates actual installed and running duration) = true indication. All off road engines use this standard. Both OEM and aftermarket. There is no other way to compare. Cheating can be done by using 0 lash / valve clearence compared to using actual lash. Zero lash will show a higher duration. Monster specs are at recommended lash.
(note that japanese cars also use 1mm valve lift. And american cars use 0.050" valve lift, but they can use lifter lift too because they have different available rocker arms / ratio's. And lifter lift can allow a better description of what your buying)
IVO = intake vlve opens at _* before top top dead center
IVC = intake valve closes at _* after bottom dead center
EVO = exhaust valve opens at _* before bottom dead center
EVO = exhaust valve close at _* after top dead center.
To get the duration.
2006-2008 stock
intake = 5 + 180 + 45 = 230* duration
exhaust = 50 + 180 + 0 = 230* duration
Overlap = the degrees between intake opening and exhaust closing.
Stock = 5* + 0* = 5* overlap.
2009+ stock
intake = 5 + 180 + 45 = 230* duration
exhaust = 55 + 180 + 5 = 240* duration
Overlap = the degrees between intake opening and exhaust closing.
Stock = 5* + 5* = 10* overlap.
Monster Cams
intake = 20 + 180 + 62 = 262* duration
exhaust = 64 + 180 + 15 = 259* duration
overlap = 20* + 15* = 35* overlap.
Cam 101
Specs are measured at .040' / 1mm valve lift. (this will take out any lash and dictates actual installed and running duration) = true indication. All off road engines use this standard. Both OEM and aftermarket. There is no other way to compare. Cheating can be done by using 0 lash / valve clearence compared to using actual lash. Zero lash will show a higher duration. Monster specs are at recommended lash.
(note that japanese cars also use 1mm valve lift. And american cars use 0.050" valve lift, but they can use lifter lift too because they have different available rocker arms / ratio's. And lifter lift can allow a better description of what your buying)
IVO = intake vlve opens at _* before top top dead center
IVC = intake valve closes at _* after bottom dead center
EVO = exhaust valve opens at _* before bottom dead center
EVO = exhaust valve close at _* after top dead center.
To get the duration.
2006-2008 stock
intake = 5 + 180 + 45 = 230* duration
exhaust = 50 + 180 + 0 = 230* duration
Overlap = the degrees between intake opening and exhaust closing.
Stock = 5* + 0* = 5* overlap.
2009+ stock
intake = 5 + 180 + 45 = 230* duration
exhaust = 55 + 180 + 5 = 240* duration
Overlap = the degrees between intake opening and exhaust closing.
Stock = 5* + 5* = 10* overlap.
Monster Cams
intake = 20 + 180 + 62 = 262* duration
exhaust = 64 + 180 + 15 = 259* duration
overlap = 20* + 15* = 35* overlap.