6 replies to this topic

[shawsy]

Does anyone know what ratio a standard set of cooper s forged rockers are?

Are they 1.3:1 or 1.5:1 ?

[glenboy]

Cooper S forged rockers are 1.27, but i read somewhere that when measured they are actually 1.23, so somewhere between the 2

Does anyone know what ratio a standard set of cooper s forged rockers are?

Are they 1.3:1 or 1.5:1 ?

[Spitz]

Does anyone know what ratio a standard set of cooper s forged rockers are?

Are they 1.3:1 or 1.5:1 ?

I also read somewhere that they are actually a lower ratio than the standard pressed steel ones.... perhaps even lower than the 1.23"

[shawsy]

Does anyone know what ratio a standard set of cooper s forged rockers are?

Are they 1.3:1 or 1.5:1 ?

I also read somewhere that they are actually a lower ratio than the standard pressed steel ones.... perhaps even lower than the 1.23"

what is the 'supposed' to be ratio of the standard rockers fitted to a '89 998cc. I'm currently running a 276 cam but need to replace my standard rockers as they have worn but i don't wont to 'decrease' performance.

[Asphalt]

I think it's safe to say they are all between 1.2 and 1.3:1. If I remember right, David Vizard writes that there are bigger variations/tolerances amongst them all. If you want to know it with scientific precision - measure your rockers. You may find out the all differ a bit?

If you want a little more lift; there are offset rocker bushes available. But they only fit pressed steel & forged cooper S rockers. I never tried them myself, but I was told they are a right pain to fit properly.

[shawsy]

I think it's safe to say they are all between 1.2 and 1.3:1. If I remember right, David Vizard writes that there are bigger variations/tolerances amongst them all. If you want to know it with scientific precision - measure your rockers. You may find out the all differ a bit?

If you want a little more lift; there are offset rocker bushes available. But they only fit pressed steel & forged cooper S rockers. I never tried them myself, but I was told they are a right pain to fit properly.

I was gonna buy some cooper s forged ones as a replacement to the standard fit, if its comparible ratio they'll be good.

What are peoples thoughts on fitting pressed steel 1.5:1 ratio with the 276 cam and flat top pistons?

I had 1.5:1 roller rockers before going for the cam and combined i think the valves just touched the piston at TDC so i sold them. Do you think there would be a problem running the pressed steel versions with the 276 cam and flat top pistons?

Thanks

[nzmember]

The reproduction Cooper S rocker from MiniSpares is NLA. Do you mean the excellent MinisSpares forged high lift rockers? They are 1.5:1.

Flat top pistons - 998cc? You'd be better of with a set of MiniSpares 1.3 roller tipped rockers. More lift and consistent than any standard rocker, 1.5:1 is too much for a small bore engine and will give you a longer engine life as the 1.5:1 will rapidly wear out your Kent 276 cam.