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

[stugray]

WEB cam supplied the cam card

That's funny because it says Type IV store right across the top of it.
And it says ON THE CARD - VALVE LIFT: .368, .368.

Are you trying to tell me that I am supposed to shoot for .368 lift AT THE VALVES?

I am trying to follow Jakes instructions to the letter, and when he says you have to meet the cam card specs to within 5% after multiplying by a rocker ratio of 1.3:
.368 * 1.3 = .478 however on my Intake valve I get .548.
Last time I checked .548 is not within 5% of .478.

So I guess you are right - I am off my Meds.

And I never said ANTYTHING about webcam not knowing what they are doing.

I am also reading on Jakes cam instructions that I need .050 clearance from the Intake valve to the piston, but I WILL have only 0.023, so I guess i should just go with it?!?!

And What "Issues" have i had? I measued my deck height and discvoered that I had sunken registers. I had them fixed just like most of the pros on this forum said is normal for these engines. I bought a race cam and i am having the exact "issues" that most people said i would have. I dont get the "issues" you are talking about. As far as i can tell everythign is working just like it is supposed to after i bought the correct measuring tools.

The "issue" I am having now is that if I follow Jakes instructions to the letter, the numbers do not add up. Therefore I as the question: Are 1.4 ratio Intake rockers normal?

Stu

[ChrisFoley]

I am also reading on Jakes cam instructions that I need .050 clearance from the Intake valve to the piston, but I WILL have only 0.023, so I guess i should just go with it?!?!

.050 is too close for an intake valve IMO. I don't like less than .120 in a race engine, .080 on the exhaust valves.

The valve lift numbers you're getting are suspicious.
There is no way you should have .548 intake lift.

It's pretty hard to believe that you have intake rockers with a ratio of 1.4.
I've never seen anything close to that, and if they are, that's desireable in an engine built for a race class requiring a stock cam and rockers.
I would trade you for them.

Either the cam is bad or there is something wrong with your geometry or measuring setup.

And the cam card is fubar - reminiscent of military-like precision. (IMG:style_emoticons/default/lol-2.gif)

[Jeff Hail]

I am also reading on Jakes cam instructions that I need .050 clearance from the Intake valve to the piston, but I WILL have only 0.023, so I guess i should just go with it?!?!

.050 is too close for an intake valve IMO. I don't like less than .120 in a race engine, .080 on the exhaust valves.

The valve lift numbers you're getting are suspicious.
There is no way you should have .548 intake lift.

It's pretty hard to believe that you have intake rockers with a ratio of 1.4.
I've never seen anything close to that, and if they are, that's desireable in an engine built for a race class requiring a stock cam and rockers.
I would trade you for them.

Either the cam is bad or there is something wrong with your geometry or measuring setup.

And the cam card is fubar - reminiscent of military-like precision. (IMG:style_emoticons/default/lol-2.gif)

[size=5]

Oh sheet. Could not have said it better. Love it when Chris shoots the Howitzer. Boom.