1.5 vs 1.6 rockers

360duster said
Hi,

i did the change from 1.5 to 1.6 Rockers some years ago, crane ductile iron 1.5 to mancinis version of the Harland Sharps. Car was significantly faster, two tenth. Could be influenced by track conditions or weather, so i think it was worth a solid tenth.

Michael

I agree and it’s what I have seen although it is purely combination dependent.

dartfreak75 said
My question is, is there a cheaper budget set of 1.6 rockers? The harland sharps cost nearly a grand that just seems ridiculously expensive to me.

Mancini racing has a excellent deal going I now with sets labeled under there own name made by Harland Sharp. Under $500. Pay attention to what your getting with the set.

mbaird said
Why would the duration change ?

The duration changes because the higher rocker ratio is lifting the valve off the seat sooner and quicker. Even though both rockers are being activated at the same time, because the cam says so, the quicker movement at the valve is due to the increased ratio.

This quicker and more aggressive lifting of the valve acts like the cam is approximately 2* larger overall except the actual start of the lift with a quicker, more aggressive ramp. The overall curve of the cams lift is increased and becomes more aggressive.