Originally Posted by SSDiv6 (Post 655093)

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.

Originally Posted by Jeff Stout (Post 655094)

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.

Originally Posted by Frank Castros (Post 655081)

You're correct about their ability to properly check Cam Duration and shame on the N.H.R.A. for that.

Originally Posted by Larry Hill (Post 655100)

I for one have had, lifter problems both ceramic and steel, cast core cam failure, and an oil pan full of steel shavings from a ceramic lifter failure on a steel cam. Each time a failure occurred we lost everything but the heads, intake, rods, and sheet metal. I put eight sleeves in a block, the block broke after a few runs.

Originally Posted by GUMP (Post 655105)

What do you feel are the major contributor to these failures? I'm just curious, but have these motors always had these problems, or did they surface due to any particular enhancements?

The demand for roller lifters seems to be presented as a way to cut costs. Could the same argument be made to take a step back to simpler times?

I'm not picking. I respect you and know that you work hard.

Originally Posted by SSDiv6 (Post 655111)

Darren,

The biggest contributor of failures is dissimilar materials, finishes, treatments, changes on the engine oil additives/composition and break-in process.

The camshaft lobes and lifter surfaces are high load contact areas, and although they may be considered highly polished contact areas, immersed or sprayed with oil, there is still some surface asperity or roughness and the reason why many engine blocks have enclosed camshaft tunnels and many enclose the camshaft tunnel area.

Flat tappet camshafts and flat tappet hydraulic and solid lifters, also need to have a specific taper on the lobe and lifter crown. I have seen too many aftermarket camshafts and lifters that have been ground without enough taper, preventing the lifter to rotate, especially with high pressure valve springs. Many of the ceramic flat tappet lifters that I have seen,do not have any taper on the crown, therefore, you have a very high contact area that eventually will wear, causing a catastrophic failure. When you have the proper taper, the engine will require a camshaft thrust plate or stop to control its movement. Nevertheless, when you have a thrust plate or stop, you also need to have the appropriate clearance because being too tight, will also prevent the rotation of the lifter.

Material compatibility between the camshaft and lifters is also a big source of failures and also the lack of Zinc and other oil additives are also a culprit. My preference of break in oils is Maxima or Joe Gibbs.

For roller cams, I recommend the use of a Calcium Sulfonate based grease or lubricant such as Lubriplate 130-AA Multi-Purpose Calcium Type Grease. Calcium Sulfonate based grease is designed for high contact areas and I apply it to the roller camshaft lobes only.

Originally Posted by john ancona (Post 655077)

There you go again putting your spin , I never said 1500 racers want rule changes , I am sure have none of the changes on your car that have moved us closer to Super Stock !