Cam Lobe Centre Adjustment

[Signal]

I have been trying to think this through and end up chasing my own tail.

To bias the peak torque lower in the rev range the lobe centre is advanced from the manufactures advertised specification.

If a cams inlet lobe centre is advertised as 100.5 deg. ATDC then to advance it 1 deg. what is the new lobe centre. Is it 101.5 or 99.5 deg. ATDC.

I think the smaller number is correct but would like confirmation.
Thank you in advance.

 

[TwoManyXS1Bs]

99.5

You're advancing the cam, so put simply, rotate it forward relative to the crank.
Or, rotate the crank backwards relative to the cam, so the ATDC number on the degree wheel decreases.

So, ATDC numbers decrease, BTDC numbers increase (earlier in the stroke)...

 

[Signal]

Thank you.