Explain to me again, please

[Jeff Stout]

Originally Posted by SSDiv6

I worked for a period of time for the former engine shop director for Robert Yates, Penske Racing and later on, Richard Petty. He spent lots of time sharing tidbits of the technology used in NASCAR on racing engine building. The only aspects that I see are advanced in NASCAR is the machining processes, equipment and materials used in the parts for longevity. Of course, they also spend millions on R&D and testing, and yes, we run more radical camshafts. Nevertheless, some of the qualifying engine cams have radical profiles and spent lots of hours and days doing Spintron testing, learning to control the valvetrain that is one of the main keys for making power.

As regards to camshafts, the cores are billet and treated. The camshafts are not broken in th engine. Every camshaft is broken-in by installing the cam in a specific machine the simulates the lifter contact and load, and different RPM levels and temperatures, being sprayed with engine oil during the operation. After the camshaft was broken in, then it would go into the assigned engine. The choice of hardened steel solid lifters made by either Trend, PPPC, Isky and Crower.

The other key for making power in NASCAR is sealing the engine, spending lots of time testing hone finishes and piston ring materials and configurations. All the torque plates we had in the shop, were custom made. The thickness of the torque plates mirrored the height of the actual cylinder head, with all the fasteners and hardware having the same length and diameter as the ones used in the engine. They were not the normal thickness of torque plates used by most shops, and many of the torque plates had provisions for hot honing.

There is more to building a fast engine than putting a big cam and stiffer valve springs.

Just talking about valve train today at shop. What was done to control valve train when using a Spintron?
Pushrod deflection, particular valve sping pressure ect.

[SSDiv6]

Originally Posted by Jeff Stout

Just talking about valve train today at shop. What was done to control valve train when using a Spintron?
Pushrod deflection, particular valve sping pressure ect.

Jeff,
Valvetrain behavior is affected mainly by the dynamics of the camshaft lobe and rocker arm and pushrod deflection. As a result, Spintron testing has helped with the reduction of spring pressures, the use of stiffer pushrods and many have switched from aluminum rockers arms to CNC machined/profiled steel rocker arms with Jesel shaft rockers. Like my friend Robin Wright says, the key is to control a "pissed off" valvetrain.