Cam price question to all

[HKZ Bob]

Dear All,
when I inspected my cam I saw some weird thing. My cam lobe spread between intake and exhaust is on the left bank 140degrees and for right bank is 17degrees.

Now I saw on the web the same thing. This is weird.
As you see in the red circle the spread between TDC lobe ist not the same on intake & exhaust.
Is that normal ?





Bye the way your price is a bless on your 911. Long life and lots of HP.

Thanks
bob

[HKZ Bob]

Here one more exapmle

[cgarr]

Normal, Its because they are left and right and look at the firing order it will make more sense. Something else, look at the heads, they are on opposite sides but yet the cams turn in the same direction, that might help too:

[HKZ Bob]

I am trying to follow but I canīt

Look at the tdc lobe between left cam & right cam.

Intake & exhaust tdc lobe are almost opposite and on the other cam they are only 17 degrees seperated.

That means to me once the intake valve is open the exhaust will follow 17° later.

on the opposite bank it is different.


Thank for your explanation

Bob

[CruiseControl]

Bob
The contact point for the inlet valve rockers and exhaust valve rockers to the cam are offset at a guess 100 to 120 deg. (not in line). The cams turn in same direction (anti-clockwise) and with the inlet valves on top on both sides this requires the inlet/exhaust cam lobes, left to right, to be positioned different to each other.
Take a point on the left cam and rotate it anti-clockwise. From the vertical position it will address the inlet rocker first then the exhaust rocker some 120 deg later. Now do the same with the right cam and the exhaust rocker is addressed first then the inlet.
Draw yourself a few diagrams.



Paul