question help
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Joined: Dec 2003
Posts: 623
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From: Point Marion PA.
Car: 1982 CAMARO;
Engine: 1985 LB9;
Transmission: T-5/
question help
ok I have a question, I would like to know how to figure out how Changing Rocker arm ratio and what lift & duration would be.
Ok I am going to have Comp Cams Custom Grind me a HR With the specs of a LT4 HOT Cam only it will be
Ok what would the specs be at 1.6 rocker arm ratio
The reason I want this cam ground with LT4 Hot Cam Specs at 1.5
is because it is a proven cam Depending on heads and intake but it would allow me to go bigger lift just by changing to 1.6 Rockers
Also does rocker arm ratio have any effect on cam duration?
Ok I am going to have Comp Cams Custom Grind me a HR With the specs of a LT4 HOT Cam only it will be
Code:
W/1.5 Rocker Arm
Lift@.050 .525/.525
Duration @.050 218/228
Lobe Seperation 112 The reason I want this cam ground with LT4 Hot Cam Specs at 1.5
is because it is a proven cam Depending on heads and intake but it would allow me to go bigger lift just by changing to 1.6 Rockers
Also does rocker arm ratio have any effect on cam duration?
Supreme Member
Joined: Jul 1999
Posts: 18,457
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
Divide valve lift by 1.5, mulitply the result by 1.6.
Changing the ratio changes the lift by that amount. It changes the duration only very slightly. The "lazier" the cam ramps, the more the valve duration changes, which is of course what the engine actually "sees"; the cam's "rated" duration however does not change, because that's usually specified as measured at .050" of lobe lift. In any case it's rare that even the measured valve duration changes by more than a couple of degrees, in the real world.
Changing the ratio changes the lift by that amount. It changes the duration only very slightly. The "lazier" the cam ramps, the more the valve duration changes, which is of course what the engine actually "sees"; the cam's "rated" duration however does not change, because that's usually specified as measured at .050" of lobe lift. In any case it's rare that even the measured valve duration changes by more than a couple of degrees, in the real world.
Thread Starter
Senior Member
Joined: Dec 2003
Posts: 623
Likes: 0
From: Point Marion PA.
Car: 1982 CAMARO;
Engine: 1985 LB9;
Transmission: T-5/
so by doing that way it would be
W/1.6 Rocker Arm[code]
Lift@.050 .560/.560
Cool Thanks for the quick reply
W/1.6 Rocker Arm[code]
Lift@.050 .560/.560
Cool Thanks for the quick reply
Last edited by MTPFI-MAF; Jul 15, 2004 at 03:44 PM.
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