For many Ford enthusiasts, merely uttering the words modular engine conjures thoughts of complexity and uniqueness. The overhead camshaft design and different-looking cylinder heads have the die-hard pushrod-engine crowd confused. In addition, the valves open and close using a camshaft on top of each cylinder head-a far different way of doing things when compared to its in-block cam cousin, the pushrod engine.
Despite their uniqueness, modular motors are susceptible to the same shortcomings as its 302 and 351 brethren-friction in the valvetrain and a loss due to flexing of the components used to push the valves open. There's also a stabilization issue that can be improved upon with better-than-stock parts. Eliminating as much friction and flex as possible by adding stronger parts will yield more horsepower due to efficiency and valvetrain stability at increased rpm.
It's common practice to swap out the stamped rocker arms in 5.0-liter combinations and replace them with roller rocker arms. The positive power results have been proven time and time again in the pages of MM&FF. While those rocker arms are pretty much standard issue in the pushrod segment of the industry, they were rare in the modular world-until now.
Jesel Valvetrain recently introduced its double roller cam followers as a replacement for the OEM stamped-steel units. The cam followers are designed for use with hydraulic roller camshafts and solid roller cams, so long as Jesel's solid lash posts are also used. Cam followers are a self-described item and are the equivalent to rocker arms on pushrod engines. They connect the cam lobe to the tip of the valve.
A reduction in friction comes through the use of needle-bearing rollers on the valve tip and camshaft. The use of that type of roller prevents scrubbing and galling caused by intense spring pressure and high-rpm operation. The body of the cam followers is CNC-machined from aircraft alloy steel that's heat-treated for added strength. Features such as those are what make these components a must-have for any serious street/ strip modular engine. The drawback comes in the expense of such components (priced at $115 per follower), but the old adage holds true in that you get what you pay for. They're worth the expense.
High-end racing engines will benefit from converting to Jesel's solid lash posts and matching cam followers. Lash posts are the equivalent of lifters in a pushrod engine. Jesel builds its lash posts to be adjustable, using a variety of shims to get the proper valve lash. The tip is designed to stay engaged with the cam followers. Switching to the solid lash posts has the same added benefits as a solid roller lifter. They're able to use a more aggressive camshaft lobe and have a greater lift with severely increased rpm. It's common for race-oriented modular engines to see the high side of 9,000 rpm. We've even heard of a few racers checking out the 10,000- to 11,000-rpm zone. That amount of rpm certainly requires solid lash posts and sturdy cam followers to prevent valve float and possible valvetrain failure. Solid and hydraulic style cam followers are sold in Two-Valve and Four-Valve configurations, and Jesel is working on a design for Three-Valve engines.