3 replies to this topic

[idlethumbs]

Hi all.
I am looking at getting some head work done on my 1275 cooper spi. Opening it up to the equivalent of stage 3.
I am not looking at doing the cam as don't want the engine removed so looking at rockers instead.
Should I be going to double valve springs?
I don't really understand it all, but I guess more power and/or higher lift rockers needs stronger springs?

[ACDodd]

Aea 525's from minispares is all you need.

Ac

[Ethel]

Stronger springs are to accelerate the valve gear fast enough to keep it in contact with the cam at higher rpm. Lighter rockers with a higher ratio help this to some degree anyway. Double springs damp each other to control bad harmonics, but quality single springs can work adequately well. Springs that are stronger than needed waste power and increase wear.

[idlethumbs]

Thankyou both. That gives me a little more understanding. I'll get the springs and rockers come payday.