I have been looking for a program that will calculate cam lift and rocker arm ratio. i.e. I have a 496/520 lift cam , and using a 1.7 rocker would result in a higher lift on the valves without changing the cam, but what would the #'s be????? Thats what I've been trying to find. Can anyone help me out here.? Thanks,, Steve

 

Use the desktop calculator that comes with windows or a handheld calculator. Multiply your cam lift times the ratio.

.496 X 1.7 = .8432

-Simple!

 

I'm assuming you're talking about a Windsor engine, they have a stock rocker arm ratio of 1.6, so.....

.496/.520 divided by 1.6 gives you the lift at the cam, .310/.325 respectively,
now multiply that by new rocker arm ratio of 1.7 gives you the new lift at the valves,.527/.553
Hope that is what you were looking for.

 

Yep! thats it, now I know LOL. Helps when you know these things when making decisions that may make it or break it, Don't want that to happen. Thanks, Steve

 

.496 is the valve lift you need to know the lobe lift to figure out total valve lift with a specific rocker arm ratio.

 

He didn't specify, he just said "496/520 lift cam". He did not specify what he was working on or what he was looking for. He could have been working on anything from a lawnmower to an industrial engine. The numbers were a little big for a lawnmower tho. Figuring lifts, ratios, etc is easy, -just basic math. No "program" is necessary. You can even do it with (gasp) pencil and paper...

 

Hey Torque,
Can you describe this "pencil and paper" thing, I know not where of you speak. I figured that was what you were thinking, although .8xx lift would have put him in the Pro Stock cam catagory.

 

I wasn't trying to be a smart guy, just giving my two cents.

However, I would think since he posted on a Ford forum he was talking about a vehicle and not a lawn mower. The lifts he was giving is a typical lift for a V8 motor. It is also obvious those lift values he indicated would be in reference to "cam lift" and not lobe lift.

 

We get all kinds of questions here so there is no telling what he wanted. Users often do not give enough information. We can't read minds.