A peek inside the transformation of a factory Viper engine into a race product and tips on sealing an engine highlighted Monday’s early afternoon sessions at the 2013 Advanced Engineering Technology Conference in Indianapolis. Lee Carducci, president and CEO of Arrow Racing Engines, gave a presentation titled “How to Embrace and Transform the Latest OEM Engines and Technology into Competitive Race Engines.” Greg West and Ron Rotunno of Federal Mogul talked about “Inside Sealing – Fel-Pro LaserWeld Technology.”

Lee Carducci of Arrow Racing Engines

Carducci presented an enjoyable discussion on the development of the Viper engine and how it’s adapted to a variety of racing applications. While somewhat short on specifics — even information on dyno charts were redacted — the overall emphasis was that a good production engine can be a great racing engine.

The Viper’s version of the V10 engine (it originally was built for the Ram pickup) was developed in conjunction with the Lamborghini Formula 1 program (Chrysler used to own Lamborghini). Some cooling, oiling and structural tricks learned in F1 carried over to the Viper block design.

“The goal was to get the thermals the same throughout the engine,” says Carducci.

Billet main caps are used in some extreme-horsepower applications but factory forged units are suitable for most other uses. One tip he did pass along was that the cam bores along with cylinders are finished honed with torque plates in place.

“The cylinder head clamping has a significant effect on the cam bore,” he says.

Many of the upgrades or changes to race engines are routine in stepping up to a race application, such as replacing factory rods with forged steel units and designing the head to allow for larger valve springs. Carducci did explain the reasoning behind eliminating the factory’s variable valve timing system — which is accomplished with cam-in-cam technology — with a traditional camshaft, noting that prototype cam lobes cost about $10,000. Also, there were concerns with generating enough oil pressure to manipulate the hydraulic cam phaser, which must overcome the high spring pressures needed for a competition engine.

Another neat innovation for Viper road racers was a swinging oil pickup to alleviate oil starvation when driving through turns. In demonstrating the versatility of the Viper 10, Carducci noted that Arrow builds engines for both the Drag Pak Challenger that races in NHRA Super Stock and also off-road trucks.

Fel-Pro touts advantages of MLS head gaskets

In the Fel-Pro presentation, West described the differences between a composite wire-ring design and the new multi-layer steel gaskets and noted that a composite gasket will work in most mild performance and street applications. However, MLS offers better sealing capability at higher cylinder pressures associated with boost or high-horsepower engines.

“They also decrease cylinder head lift,” adds West.

A key advantage with MLS gaskets is the emboss bead around the bore functions as a spring. In fact, Fel-Pro indicates that the height, width and shape of the emboss beads actually the “spring rate.” When the cylinder fires, the head tries to separate from the block due to the cylinder pressure. But excessive lift is a major cause of combustion leakage. Acting in a spring-line manner, the MLS gasket continues to seal because it continues to fill the gap during the lift. Part of the demonstration highlighted the extensive equipment Fel-Pro has developed to measure head lift and cylinder pressure during development of the MLS gasket. Fel-Pro’s data demonstrated how much cylinder pressure increased during pre-ignition and detonation conditions, especially when peak pressure happens closer to TDC than a few degrees past TDC, as in normal operating conditions. Ensuring proper ignition timing is also critical in reducing the chances of detonation.

“We’ve gotten real good at making sure the timing in the Number 1 cylinder is right,” quips West, noting a bent fin on a reluctor wheel can offset the timing dramatically in a single cylinder and cause considerable havoc.

In summing up, the keys to reducing head lift included using the appropriate block and cylinder head for the applications, i.e. an LSX block with additional bolt holes for high boost, using appropriate fasteners, applying the proper clamp load and avoiding spikes in cylinder pressure. Providing a proper finish on the block and head surfaces is also important.

“You need a smooth finish for MLS gaskets,” says West, noting that the thin coating on the MLS gasket has to fill all the peaks and valleys of a rough finish.

Fel-Pro suggests using a profilometer to measure surface finishes and stresses that the engine builder should be more concerned with the Rz numbers than the Ra profile.

Rotuno pointed out the advantages of using molded rubber gaskets for the valve covers and oil pan but also stressed that RTV sealant not be used to secure the gaskets. This action can easily cause the gasket to slip from its intended position.

In wrapping their presentation, Rotuno and West profiled Fel-Pro’s extensive facilities as the company celebrates its 95th anniversary.