Roller Cams in Stock Eliminator?

[Bernie Cunningham]

Dang, Nascar CUP cars, the big boys, have just recently switched to roller cams and lifters, imagine the beatings that the old flat tappet set up took and yet it stayed together.

Yeah, they also dropped the max RPM as well but before that you had an engine running non stop for hours at WOT at around 9K plus RPM. Very impressive indeed.

[Dan Fahey]

Going to Roller Cams.
The racers will have new geometry to play with.
More Spring, Duration and new level of breakage.

Roller Cams will yield higher rpm.
Leading to more and impressive dramatic catastrophic failure!

Need a spring limit rule to back off from limits of material science.

D

[Bernie Cunningham]

Originally Posted by Bernie Cunningham

Dang, Nascar CUP cars, the big boys, have just recently switched to roller cams and lifters, imagine the beatings that the old flat tappet set up took and yet it stayed together for decades.

Yeah, they also dropped the max RPM as well but before that you had an engine running non stop for hours at WOT at around 9K+ RPM. Very impressive indeed.

I would like to bring this back up as it's got to be relevant.
Does anybody know what the, before roller, spring pressures were on a Nascar CUP car?

[Bill Diehl]

Originally Posted by Bernie Cunningham

I would like to bring this back up as it's got to be relevant.
Does anybody know what the, before roller, spring pressures were on a Nascar CUP car?

Its irrelevant....they have 6 and 7mm valve stems in the 60 to 70 gram range with a spintron designed valve train with the proper geometry, they use less spring pressure than you would think.

there is a thought ..lower the pressure so you can spend thousands of dollars on spintron testing.......what a concept

[Rick Leininger Jr.]

Originally Posted by Bernie Cunningham

I would like to bring this back up as it's got to be relevant.
Does anybody know what the, before roller, spring pressures were on a Nascar CUP car?

100 lbs. on the seat, 500 lbs. over the nose, loft enabled valve motion and hp similar to what a roller profile would provide.

Not all the 396 375 guys are blowing up
their stuff. Sounds like the ones that are having problems should go see the engine builders of the ones that are not. Or back
The rpm down below 8300 or whatever they are trying to turn them too. Changing cam profile will help valvetrain failure.

I've heard of places that will run a cam and lifters on a special machine that breaks in the lifters to a new cam. Maybe that's an option, even before you run it in an expensive engine. Just a thought. If the parts are broken in properly the tool steel lifters are supposedly very reliable.

I keep beating a dead horse with this suggestion, but go and test some valvetrain parts on a Spintron.

Instead of lobbying for parts to cover up for a lack of understanding of what is going on in your engines valvetrain wise, try to do some research and talk to people that figure things out.

If you live close to Pa go see Ray and Dave Barton. They have a Spintron machine and have worked on all kinds of engine combos. I'm sure they would be able to fix the problems you are having.

Or

Lane Line, Brian Tilburg, Steve Ficcaci, and Darrel Weikle are some guys that build
Very fast and reliable 396 engines that last and win races. Save your money and go see any of the above people.