Anyone have a problem with it at high rpm? I don't see it as a problem since nascar motors use them for hours on end at 10k rpm. I'd rather not use roller tip rockers because of the added mass (and price), but this thing will live around 7k rpm. Spring pressure is pretty mild, only about 300# open.

 

i've never heard of it. nascar has few problems like that because they use the best parts. you shouldn't have any problems with occasional 6-7k rpm bursts

 

Looks like roller tip rockers to me.

http://www.hotrod.com/techarticles/h.../photo_05.html

 

How'd you come up with NASCAR engines using those rockers?

Just for info sake, the last info I read on NASCAR engines has them using 2.1 rocker ratio; engine life expectancy is 800 miles or 5 hours, whichever comes first.

That's why the crews pay such close attention to how much is put on the engine during qualifying. As you may know, NASCAR use to allow a qualifying engine and a race engine, but that rule was changed. Now, what they qualify with gets sealed an can't be changed without the car going to the back of the pack on the race day starting grid.

I'm not up on ALL the NASCAR rules, but I'm sure if the engine gurus have their choice, they'd run a shaft setup, like Jesel's stuff.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

Another thing I just thought of:

I watched this years NASCAR Sprint race held at one of the fastest (or maybe THE fastest) tracks they run, here in TX. I watched the RPMs and the engines were running 7k-9.2K. Occasionally an engine will hit 9300 at the top of the straight away or drop as low as 6800 in one of the corners. None even came close to 10K. It seems the engines were tuned for the 7K-9.2K RPM range.

Now, the Pro Stock boys often play with that magical 10K number.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

 

I was under the impression that's what they used. I don't pay much attention to nascar, if I can't go to my local track and see it I lose interest.

 

The Chevy NASCAR boys run what's call a GM R07 engine. It's entirely different from what we run and have no interchangable parts with ours. The block even has wider bore spacing than ours.

When it comes to the heads, they're completely different from what we've come to expect in a SBC. GM even did away with the side by side center exhaust ports which means the valve arrangement is completely different than ours. They have cast in oil channels to help cool the valves springs, and a LOT of other sorts of changes too numerous to list here.

Even with all that, they have a short life span because they're pushed right to the limit. In a recent NASCAR race ran here in TX, they were running 7k to 9.2K - Occasionally one would drop 6.8K or top out a 9.3K, but the general, most often seen RPM range was 7K to 9.2K.

I don't keep up with them all that often either, I just drop in once in a while to see what they're up to. In fact, I only recently learned that some teams have moved their camshaft research, development, testing and grinding in-house. Many, if not most, had formerly used CompCams; some may still. Now those cams are proprietary; meaning we can't find out what specs they're running; Super Secret Stuff! Ever wonder what cam Jimmie Johnson's running? I'll bet all the others do; even Jeff Gordon - although they're out of the same stable.

But all in all they're NASCAR Chevy engines are completely different animals.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!