Cam and Rocker Ratio
Thread Starter
Melting Slicks
Joined: Sep 2002
Posts: 2,783
Likes: 2
From: Engineers do it better.
Cam and Rocker Ratio
Rookie Question: Does the selection of cam depend on the rocker ratio?
i.e. I am looking for a cam with under 0.500 lift (due to CC-981 springs), does this mean I can only use a cam with 0.468 lift if I use 1.6 ratio? That's what I was told by a tech at CC. He told me to use XS256S cam or XE262H cam. Seems too small for my Sportsman II heads
Please explain. Thanks in advance
i.e. I am looking for a cam with under 0.500 lift (due to CC-981 springs), does this mean I can only use a cam with 0.468 lift if I use 1.6 ratio? That's what I was told by a tech at CC. He told me to use XS256S cam or XE262H cam. Seems too small for my Sportsman II heads
Please explain. Thanks in advance
Racer
Joined: Nov 2001
Posts: 379
Likes: 0
From: Helsinki
He's correct. The 0.468 inch valve lift is calculated using theoretical 1.5 rocker ratio, so the actual cam nose lift is 0.468 inch / 1.5 = 0.312 inch.
Using 1.6 rocker ratio, the valve lift will be 0.312 inch x 1.6 = 0.4992 inch. Just under 0.500 inch :-)
Using 1.6 rocker ratio, the valve lift will be 0.312 inch x 1.6 = 0.4992 inch. Just under 0.500 inch :-)
