The world’s first aftermarket Cleveland crate engine was unveiled recently by the Waldorf, Maryland, firm McKeown Motorsport & Engineering (MME). They call it Titus.
Though MME’s Titus crate engine distinguishes itself from its mighty predecessor of the 70’s and 80’s in many ways—internally balanced forged crankshaft, deck-plate bored and honed, priority mains wet- or dry-sump lubrication systems and so on—it is the multiple choices of induction systems that set it apart from the conventional crate engine. To this end MME offers five different cylinder heads for five different duties, and they require specific information to select the correct cylinder heads and induction system for every engine.
The most important element in building a high performance engine—an engine that accelerates quickly—is to know the crucial rpm range in which it will operate. It’s also helpful to understand that high average power output prevails over peak power output—always—at least in a muscle car if not a dynamometer.
In addition to stating the engine’s operating range, which influences the runner lengths of the induction system, MME needs to know the car’s weight. The induction system of a Titus engine powering a 2,000lb Cobra is obviously different to that of a 3,800lb Mustang. Gearing also has an effect on induction choice. For example, a Titus engine powering a gear ratio of 3.25:1, used predominately to propel the car at 1,500rpm along the street, dictates a different cam and induction system to that of one empowering a 4.11:1 gearing, operating at 3,000rpm. Hood clearance is a further consideration, although the Titus’s 9.2in deck height usually provides adequate top and side margins, especially convenient for header fabrication.
Finally, before selecting the right cylinder heads and induction system, MME will ponder two further factors. The first one relates to the engine’s cubic inch displacement, paying particular attention to bore size and inlet valve size. These components often dictate how the chamber and bowl (the area adjacent to the valve seat) are shaped.
The second factor to be considered is the cross-sectional area of the induction tracts together with valve size and valve angle as well as port volume and port shape. These elements regulate port velocity. Port velocities, which are measured in feet per second on a flow bench, are affected by low and high pressures within the intake tracts. Low pressure cycles occur the moment the inlet valve cracks open, revealing a falling piston within the cylinder bore. “Without optimal velocity,” says air flow specialist Keith Wilson, “you cannot successfully fill the cylinder—your volumetric efficiency will be inadequate. Moreover, optimal velocity is imperative for maintaining the weight of the fuel while in suspension, as it’s heavier than air. If the fuel loses its fine particle properties and becomes ‘wet’ it cannot recover, and most of it will exit the tailpipe unburned. Without optimum velocity, fuel falls from suspension and power is lost.”
Beyond induction issues, the Titus has benefited significantly from rapid advances in engine technology. For example, the advantages of modern electronics, both ignition timing management and fuel injection management, as well as CNC-machining, particularly in the forming of asymmetrical camshaft lobes, have had a profound influence on its personality. “But, even in its original form, I’ve always had great affection for the Cleveland,” intimated MME’s principal Mark McKeown, “I admired the efficiency of its cylinder heads, its combustion chambers, its 9-degree valve angle—the Cleveland had few vices. And even though I’ve been developing these engines for almost 30 years, I still get a thrill from working on them.”
Though engine displacements of 408 and 410cu in have traditionally been the MME staple, bigger 427 and 430cu in-plus displacements are now becoming available. Predictably, the power output most commonly chosen for street and street-strip use is between 450 and 750 horsepower.
With many different qualities to recommend the Titus, here are some of the essential stages captured during a typical pre-assembly process.
McKeown Motorsport Engineering, Inc.
10F Irongate Drive,
Waldorf, Maryland 20602
Telephone (301) 932-9292