Just to add more fuel to the TF valve lift fire (pun intended), here's a quote from Crane Cams Newsletter #86:

"Ever Wonder What Top Fuel and Pro Stock Cams Are Like?

While everyone marvels at the performance of current Top Fuel dragsters and Funny Cars, these engines’ cam needs offer a striking contrast when compared to their Pro Stock counterpart. A common “baseline” TF or FC nitro cam is our Part No. 66R000490, grind number R-298/4778-14XBB48D. This cam is 298°duration (measured at .050” lifter rise) on the intake and exhaust lobes, with .750/.726” lift, intake and exhaust. This is on a 114° lobe separation.

By contrast, a typical Pro Stock cam profile weighs in at 276° intake and 306° exhaust duration @ .050”, and a 115° lobe separation. Gross valve lift is where Pro Stock engine builders really turn it up! Using a typical 1.9:1 ratio rocker arm on a cam lobe that has .530” lift produces a gross valve lift of 1.007” … that’s over one full inch of valve lift! Such a hostile environment is where having a very “smooth” Crane computer designed cam lobe profile really pays off in HP as well as durability. Just imagine the physical forces at work in a typical 500 cubic inch, 1,400 HP, Pro Stock engine turning 9,500+ rpm!"


Those numbers are pretty much what I've heard elsewhere

 

We were running Brad Anderson heads-those and Alan Johnson are the only 2 makes at this time.

 

Correct-you don't need HUGE cam #'s in a fuel motor! The A/F ratio for nitro is somewhere near 1.7:1.

 

Thank you! That is exactly what I was trying to get across!

 

Just imagine the physical forces at work in a typical 500 cubic inch, 1,400 HP, Pro Stock engine turning 9,500+ rpm!"
=============================================

Close to the refresh rate on your monitor

your monitor is painting horizontal lines so fast in front of you the picture looks like its standing still

Frequency_Number = Engine_RPM / 120

ProStocker or your Computer Monitor at 9500 rpms ;
79.2 per second = 9500 / 120

ComputerMonitor @ 75 Hz refresh rate = 9000 RPMs

imagine opening/closing a valve at 79.2 times per second
or piston going from TDC to BDC 79.2 times per second

 

The refresh rate on my monitor is 85Hz

 

It's pretty amazing that such a weighted object can reciprocate
~ 80 cylces per second and not launch itself off of the connecting rod.

Like the story says, RPM kills and it gives a new respect to the
high performance street motor, or motorcylce engine rev'ing to
12,000 RPM.

Now that we have lift and duration ironed out for TF engines, and
magneto terms/concepts down to a science, can we all gather at
my place next weekend and shoehorn one into my Z28?

Next question. For a solid roller camshaft, I saw the tech stick a
feeler gauge between the valve stem and rocker arm. He moved
it around much too fast to be setting lash. I'm thinking they were
just checking the clearances while the lifter was on the baseline
of the camshaft.

I've never setup a solid cam, so please explain the tolerance between
the rocker and valve stem.

Wouldn't the lash be set to 'zero' with little room for a feeler of
any gauge to be slipped it? Maybe they're setting another aspect
of the valve train?

Would the tolerance allow for expansion of the metal once the
engine warmed up? IE: Set lash loose cold so that it's tight once
warm?

 

Yeah, the tech was probably just checking the lash. This was most probably after the warmup. They usually set the lash at around .024" cold, and usually at about .016 hot. Between rounds, they just set it at the 'hot' setting and go with it, usually don't even take the valve covers off after the warmup.

 

...or 316.7 times a second. (TDC to BDC and back once per rev).
9500/60 = 158 rev/sec. Fortunately the valves only see half of that as you said.

What blows my mind is the 19,000+ F1 engines. Twice the cycling rate, but very short strokes (like 1-9/16 in.) That's 316.7 revs and 633.3 trips in the cylinder per second along with 10,000gs at the piston!

 

What is the budget of a F1 racing team??? yeah i know... i give that much every sunday at church

 

What blows my mind is the 19,000+ F1 engines
===================================

OldSStroker,

why do you suppose they "need" to rev them that high ?

(HP/CID find a way to move your Torque curve as high as possible )

 

The funny thing is that i believe they are smaller engines this year and are running faster!!

 

For all of you guys dreaming of making you cars more radar obsorbent, keep in mind that a lot of states, such as Indiana, use a device called VASCAR (Visual,Average,Speed,Computer,And,Recorder). It is essentially a "stop watch" device coneceted in with the transmissions of patrol cars. It has a time switch (violators time) and a distance switch (patrol car measures the distance the violator traveled). It takes a vehicles (violator's) time and the given distance by the patrol car and gives you the vehicles average speed over the measured distance. It is very effective, it is not affected by weather or darkness. It can be used either moving or stationary (using a pre-determined distance entered into the computer). This is also what is used in the airplanes for checking speeds on the interstates. So, it has the ability to check a vehicles speed with the officer in front of you, behind you, sitting on an overpass or in the air without you knowing it. No matter what radar/laser detector that you have. It is great! By the way, I'm a Trooper in Indiana and I have used the device quite a bit, so I know that it is very effective!

 

Not technical, but noteworthy.

http://sports.espn.go.com/rpm/news/story?id=1830632

A tribute to those that risk their lives to make us gear heads
write threads like these.

 

I was told that Ferrari spends about $420 MILLION a year on F1 and they are the highest spender. Hmm, could it be a coincidence that the highest spender is also winning the most?