We are proud to offer a new High-Ratio, Adjustable Rocker Arm and Pushrod Combination for Parallel Valve Lycoming engines with the flat tappet camshaft. The increased ratio of the rocker arm increases both total lift and effective duration of the valve event. The stock Lycoming rocker arm has a valve lift ratio of 1.28:1 - our rocker arm increases the ratio to 1.43:1. While the peak valve lift is increased substantially by the increase in ratio, in reality the valve is only near the peak for a very small amount of time. The real gain from the rocker arms comes from the fact that the ratio affects the entire lift curve of the valve, which means that we get increased lift at each point of the cam lobe's rotation.

We have also developed a pushrod to compliment the new rocker arm. These pushrods use chro-moly tubes with hardened steel ends and make the rocker arms a complete bolt-on installation. The entire swap takes less than 2 hours and requires no special tools. There is no need to pull the case apart since these pushrods are designed to work with the stock hydraulic lash adjusters. Even with the increase in peak lift, the engine remains non-interference using 10:1 pistons. The minimum measured valve clearance is 0.483" on the intake side and 0.524" on the exhaust side.

By including a height-adjustable cup on the pushrod end of the rocker arm, the user can easily set valve lash to their desired requirement. While this feature can be overlooked on some installs - where the technician will set the initial height and then leave it alone, the height adjustment can be used to dial in the lobe duration when fine tuning is desired and will be essential when we move to solid lifters.

Dyno Comparison Charts - IO-360

Stock Rocker Arms:

Sky Dynamics High-Lift Rocker Arms: