What rocker arm ratios do people see? Options

[stugray]

I am adjusting the valve geometry while putting in a Raby 9700 cam and I am seeing .38 on the exhaust cam lift and .496 at the valve (an exh rocker ratio of 1.3) and I have a .39 on the intake with a .546 at the valve ( an int rocker ratio of 1.4) is this what everyone else gets for rocker ratios:

Intake rocker ratio = 1.4
Exhaust rocker ratio = 1.3

These are the 1.7 (1.8?) rockers that accept the 911 swivel feet.
I am using the swivel feet, have modified the rocker faces, adjustable push rod, and zero lash to do the meaurements.

Do those rocker ratios look like stock?

I want to take 50 thousandths off the Combustion chambers to increase the CR, but my measurements say I wont have enough clearance on the Intake valve once I shave off 50 thousandths.

I only have ~0.075 clearance now from the piston to the Int valve as it is with a deck of 0.030 and everything else (crank & rods) stock - flat top 96mm pistons.

That Intake valve travel of ~0.55 looks huge to me. Anyone else care to comment?

Stu

[nathansnathan]

"Valve lift" is taking the ratio of the stock rocker into account. "Cam lift" is the term for the lift without the ratio and may not be a figure that is on the card. Since you will be measuring at the valve retainer, you just use the valve lift figure and no mat required.

The whole point of doing your valve geometry is determining how far out the rockers need to be to get advertised lift. The pushrod will lengthen accordingly, but how far to shim the rockers is the main factor. You will have to stop shimming when the adjusters start hitting the head covers. (IMG:style_emoticons/default/biggrin.gif)