Competition piston rings and what the OEMs taught us

Competition piston rings and what the OEMs taught us

By Sam Logan:   In our racing world we tend to think of ourselves as the elite corps. But in pistons and more particularly piston ring design, it is not our racing brains that are the driving force but those of the Original Equipment Manufacturers. It would be a glum glimpse of the US racing industry if nothing changed. But it has and nothing could be more illustrative of change than ring development. In fact, if we’re not careful our tow vehicles will operate with 1 x 1 x 2mm ring packs before our race cars. And it’s not just skinny rings that’s been pioneered by the OEMs, the enduring cast iron top and second rings have been replaced by stronger and lighter steel types. Furthermore, thermal face coatings are being applied to top rings by high-velocity oxygen-fueled spray guns at supersonic speed. The force of the collision causes the face coating to become embedded in the rings. What are they seeking? Well, with regard to the thermal face coating, they are pursuing bond-integrity. Second, they are also constantly looking for improvements in overall strength and toughness of the top ring. And third they seek to lower the ring’s coefficient of friction; that is the ratio between the force necessary to move one surface over another and the pressure between the two surfaces. The high-velocity oxygen-fuel technique that applies the thermal face coatings allows the OEMs to run high-tech rings in their latest turbo applications. These are subjected to countless detonation incidents. Tod Richards, a ring specialist at MAHLE, a racer and a race engine builder marveled, “The rings...
Tough NMRA classes beg the question: What is a good clutch?

Tough NMRA classes beg the question: What is a good clutch?

By Fergus Ogilvy:   There are several schools of thought on the question of what constitutes a good clutch. But first there are two separate strands to this narrative that need to be addressed: street or track. It’s key to distinguish whether the car will be used mostly for high-performance street-travel or for track use and its purpose needs to be decided. In either case the clutch has to transmit the car’s horsepower and torque and a stock clutch assembly will flounder in thermal shock and abuse, even in a slightly modified car.   Let’s focus our attention for a moment on selecting a good clutch for a high-performance street car that visits the drag strip occasionally. In this pursuit, the first consideration is usually vehicle weight. Accurate information about the vehicle’s poundage not only guides to the proper selection of an adequate clutch but also has relevance in the selection of the most effective flywheel. Another necessary statistic is the amount of power being transmitted through the clutch. And third, let’s not overlook the gearing. Lastly, pay attention to the size and type of tire conveying the rotational energy to the road or track.   Flywheels and a simple gearing formula Lighter flywheels provoke engine speeds to accelerate and decelerate quicker while the opposite is true of heavier flywheels. Heavier street cars usually benefit from a heavier flywheel, which maintains its advantageous momentum—it inhibits engine speeds from descending too quickly. However, shedding 10 to 15lbs of mass from the rotating assembly of a properly geared vehicle has a pronounced effect on its responses. Hence, lightweight, high-revving race cars...
Remedy for Jeep’s steering ailments:

Remedy for Jeep’s steering ailments:

Solutions all hot rodders should know. By Archie Bosman: Many consider type CJ Jeeps, those in production from 1976 to ’86 susceptible to internal steering column ailments, particularly the open-top models where the column could be exposed to rain, snow, dirt and dust which hastens wear. The wear is not reflected in the steering column’s ability to turn the wheels—instead it’s conspicuous by looseness in up-and-down movement and also back-and-forth within the steering column. Many Jeeps from this era feature a steering tilt mechanism. The significance of efficient steering tilt was brought to prominence by Michigan steering specialists ididit whose history began in the mid-nineteen-eighties. At that time Street Rods were the foundation of their customer base and their multi-angle steering tilt was born of necessity. The chief annoyance among hot rodders was the awkward positioning of the steering column that was installed at a near vertical angle and never conducive to comfortable driving. This inconvenience spawned a succession of multi-angle steering tilt arrangements that increased the angle of articulation of the steering wheel and corrected the impediment. But for Jeep CJ owners, over time the tilt shaft assembly, which was offered originally as an option, became sloppy at the head of the column. The arrangement incorporates two aluminum castings and two shafts, an upper and a lower, both with forked ends. The ends are positioned 90-degrees apart and the assembly is completed with a grooved metal ball that is manufactured in two halves. Of course, the advantage of having access to a replacement steering column with efficient tilt mechanism not only rectifies potential wear troubles but also allows...
The 14th annual Holley National Hot Rod Reunion®

The 14th annual Holley National Hot Rod Reunion®

The 14th annual Holley National Hot Rod Reunion® presented by AAA Insurance, is heading back to historic Beech Bend Raceway Park and beautiful Bowling Green, Kentucky, Father’s Day weekend, June 16-18.   The Reunion features:   Heacock Classic Cruise In and Fanfest (Wednesday-downtown) • Hot Heads Eliminator Nostalgia Nitro Quarter-mile Drag Racing • Axalta Show N Shine • Dynamat Legends and Honorees • Huge Swap Meet • Manufacture and Vendor Midway. Join us in thanking our 2016 sponsors, Holley Performance, AAA Insurance, Good Vibrations Motorsports, Axalta Coatings, Dynamat, Hot Heads Racing & Research, and Heacock Classic Insurance.   Spectators call: (800) 884-6472 or online: www.NHRA.com/tickets and get your tickets today! For more information, go online to: NHRAMuseum.org and click on Reunions  ...
Ever thought of stunt car driving?

Ever thought of stunt car driving?

Police, military and film directors think about it all the time. By Freddie Heaney: Bobby Ore has made an adventure out of stunt-car driving and when his stunt operation arrived at Atlanta Motorsports Park in mid-March it was a rare opportunity to meet the man. If you could rock a double-decker London bus up onto two wheels and drive it on its  side into the Guinness Book of Records you might consider it a triumph you wouldn’t forget. Though I didn’t know Bobby Ore was the driver at the time, the sight of that bus moving along on two wheels at a precarious angle remains fixed in the mind. Now, decades later, the Oklahoma-born stunt pioneer was scheduled to appear at Atlanta Motorsports Park in Dawsonville Georgia, where his company, Bobby Ore Motorsports, is currently establishing and expanding its base. “That was back in July of 1989,” said Bobby, when “fund-raising members for the Royal Marsden Hospital conceived a campaign to drive a London double-decker bus around the world. Princess Diana was the hospital’s President and they needed a stuntman to launch the bus up onto two wheels. It was a spectacle contrived to attract as much initial television exposure as possible—and it succeeded! ” Since then Ore has masterminded the art of teaching stunt-driving with bases in Sebring, Florida, Camarillo, California and now North Georgia. But why Georgia? “Well, we’ve always provided driver training to military personnel as well as law enforcement officers, but the film industry plays a significant part of our business too.” In 1996 Ore created the Motion Picture Stunt Driving School in response to...
Why Turbocharging? Simple advice for beginners

Why Turbocharging? Simple advice for beginners

By Doug Erber: In the United States, OEM’s (Original Equipment Manufacturers) are turning to turbocharging as a method of downsizing engine displacement and increasing fuel economy. At the other end of the spectrum, those in charge of developing high-performance and racing engines, are targeting it for substantial power gains. The OEM’s regard GDI (Gasoline Direct Injection) as a key enabler for utilizing turbochargers to downsize the engine displacement. With modern direct injection coupled to variable cam timing, added power output generated by turbo boost is now exploited more fully than before without risk of detonation yet with significant benefits in fuel economy when running under light load. As a result, OEMs are shrinking the displacement of the engine, leading to weight and fuel economy savings. However, when power is required, the turbo kicks in to provide the boost, adopting the feel of a larger displacement engine. Turbos for OEM applications are sized to provide the best combination of low-end torque and peak power. In the Aftermarket, turbocharging is a relatively easy way to significantly increase the power density of an engine. In simplest terms, adding more air and more fuel to an engine will create more power.  Of course one must take care to assure engine and vehicle systems are adequately prepared to handle this additional power. Most systems will add an intercooler to reduce intake manifold temperatures and aftermarket ECU to control fueling and ignition. Depending on boost level, consideration for upgrades include, but not limited to, cylinder head gasket, head bolts clutch, pistons, connecting rods, crankshaft, transmission and differential. All components will be exposed to the rigors of additional power.  ...