looking for 2.7RS CAM BODY EVALUATION

[HKZ Bob]

DEAR ALL;

WAYNES BOOK HAS ALL DATA ON THER CAM INCLUDES: I AM LOOKING FOR THE CAM PROFILE ON A 360° METRIC MILIMETER PAPER:

SOMETIHNG LIKE A LIFT DIAGRAMM:

IN GERMAN IT IS CALLED ERHEBUNGSKURVE

I am looking for some document like in the magic book but more detailed

All data are available:
What is the slope

What means ABDC & ATDC

5,2 intake overlap
cam lift intake 37,30
cam lift exhaust 36,44
intake opens:38° BTDC
intake closes: 50° ABDC
exhaust opens: 40° BBDC
exhaust closes: 20° ATDC

[tom1394racing]

Bob

Maybe I can help.

Here's a cam profile for an E type cam that I mapped on my homemade cam doctor.






Cams are typically specified in terms of 3 parameters

1. Lift at the valve
2. Duration
3. Lobe Center

The lift for the intake and exhaust valve if how far the valve moves off the seat at it's wide open position.

Duration is how long the valve stays open in terms of degrees of crankshaft rotation. This is 2X the camshaft rotation shown in my digram. Duration is typically specified from the time the valve opens 0.05" to the time it reaches 0.05" from the closed position

Lobe Center is the distance from the peak opening of the exhaust valve to the peak opening of the intake valve as measure in camshaft degrees.

The key parameters in the map to calculate lift, duration and lobe center are highlighted in yellow on the spreadsheet above.

The timing of the valve action relative to the crankshaft position (ie intake valve opens 38 deg BTDC) is set by the cam timing.

Here's an incomplete table of Porsche 911 camshaft specifications I have complied from several reference on this board

[HKZ Bob]

Tom
where do you set the reference of your measurement?

BR
Bob

[tom1394racing]

Bob

When measuring the cam alone, the reference does not really matter. The important specs are the shapes and location of the two valves opening and closing relative to one another.

When setting up my cam doctor, I usually set 100 deg at the opening location for the intake valve. This way both valve maps are between 0 and 360 deg on my chart.