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.

[Billy Nees]

Originally Posted by Frank Castros

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

Ya know, I think readers will find (and I hope that someone will add to this or correct me) that the major issue with 21st Century Tech (and late 20th) is that (probably) 20 or 30 years ago the Government (you all remember them, the guys looking after our best interests) "forced" NHRA to start treating Tech people like employees and paying them accordingly. Until that time, many Tech people volunteered their time or were paid a token amount. When NHRA was "forced" to pay, they just cut back the number of Techs to an absolute minimum (and beyond).
OBTW, ANOTHER reason to appreciate those "old" Tech guys!

[Larry Hill]

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. So we , a bunch of smart people that have helped me, have attained a small amount of reliability with the six pack car.

The cam is factory size journals and lift

I know the other shoe will drop sooner but I hope it later.

[GUMP]

Originally Posted by Larry Hill

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.

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.

[Dan Walcott]

I would like to see valve spring pressures for "stock" to be set at 200#'s , unless OE was more , then set at factory specs. Should remove the need for all the enhancements requested for more exotic valve train.

In my opinion , opening up the spring rule (or lack of a rule) started all this rule changing requests.

If you want a jessel , roller cam , lighter this or that , then Super Stock or comp , or? Is the Class is for You

NOT STOCK!!!

[SSDiv6]

Originally Posted by GUMP

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.

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.

[SBillinson]

Originally Posted by SSDiv6

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.

Excellent explanation.

It bears mentioning that there can also be issues with pushrod angularity. Steep angles between the lifter and pushrod will cause bias pressure on the lifter.

I have offset lifters on my modified engine to try to compensate for the difference in width between the lifters and the rocker arms. They are top-shelf lifters but even with 50 passes on them, you can see the wear pattern from the pressure bias.

The fix is to machine the block so the lifter bores align with the rockers, side to side. That way the pushrods will be straight without using offset lifters. With the splayed head, the bore angles also need to be changed front to back to remove the angularity caused by the valve/rocker placement.

The lifter bores for my application need to look like a standard BBC.

[Doug Hoven]

Originally Posted by john ancona

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 !

I'm not sure which changes you would be referring to, but both of the combinations that Todd has built throughout the past 20+ years have not been given a great deal of the "enhancements" that combinations in the same classes have been given. Ok, maybe the 12 bolt rear in place of a 10 bolt is one, but I can't imagine that rule change having a similar reaction than allowing anyone to run a roller lifter in there engine.

[Larry Hill]

Ceramic lifters failure seems to start the snowball rolling for engine destruction. We brake the cam in on a fixture, run it on a dyno, race it with break in oil and then the ceramic lets go and it’s back to square one.