rocker arms

I found some 1.3 ratio roller rockers. Designed for breaking in the engine. The cam in last year's challenge engine is a 670 lift with 1.6 a little to much for daily use but at 1.3 Becomes 544. Can you use these lower ratio rockers permanently ?

Im sure you can. I certainly understand how lowering the lift would make the engine better mannered.

I wonder where the lower lifter places the stress. I would theorize it lowers stress on the lifter/cam and increases stress on the valve springs?

If that is the case, the valve springs may need an upgrade to hardle the extra stress.

In reply to NordicSaab:

There should be no net increase in stress on the system. The stress would increase overall as the valve spring compresses, and since the valve spring compresses less, there would be less load.

Also, the fulcrum of the rocker arm will be nearer to its center, which will lower the pressure of the rockers on the cam even further.

The only thing that won't change; or will really change a small amount; is the duration and overlap of the cam. It's more like the perceived overlap of the cam will change. Since most cams will have specs listed at 0.050 lift that part of the cam events will show a reduction since the cam will take longer to achieve that lift than with the stock rockers.

stan_d wrote: I found some 1.3 ratio roller rockers. Designed for breaking in the engine. The cam in last year's challenge engine is a 670 lift with 1.6 a little to much for daily use but at 1.3 Becomes 544. Can you use these lower ratio rockers permanently ?

Basically will be like driving with the throttle blocked at 80% all the time.