Originally Posted by Vinci's Website

From Crane Cams Newsletter #184

Crane LS1 Gold Race Rockers “Too Powerful!” for Daytona!

At this year’s inaugural Grand American Road Racing Series races at Daytona International Speedway, Crane Gold Race rockers used on the LS1 powered Pontiac GTOs were declared illegal for competition because they provided “too much of a power increase!!” On their first runs in practice, the new GTOs (fielded by Spirit of Daytona Racing) were as fast as last season’s series-champion Mustang! That was without any chassis tuning or other “tweaking.” It isn’t good to be that fast “right out of the box” with a totally new vehicle. Series officials decided that in the interest of keeping competition “fair and equal” to all brands, they needed to slow down the new GTOs. They evidently had heard “rumors” that Crane’s “Quick-Lift” rocker arm geometry provided a significant horsepower advantage (14 - 15 hp at the rear wheels) over the stock rockers even with the same 1.7 rocker ratio. As a result, they declared the use of aftermarket rockers “unacceptable” and mandated the use of stock rocker arms for use in the Grand Sport Series.

Originally Posted by Vinci's website

Crane Gold Race® Rocker Arms Dominate Engine Masters Challenge



The 4th Annual Jeg’s Engine Masters Challenge, presented by Popular Hot Rodding magazine, was held this past week at World Products’ facility in Ronkonkoma, NY. This year’s competition called for big block engines not to exceed 510 c.i.d. When the battles were over, Lennart Bergqvist (Autoshop Racing Engines - Orlando, Florida) emerged victorious with his Crane Gold Race® rocker arm-equipped big block Chevy. Runner-up Tony Bischoff (BES Racing Engines - West Harrison, IN) also relied on Crane rocker arms, as did two-time champion, Jon Kaase (Jon Kaase Racing, Inc, - Winder, GA) who came in fourth with his unique Pontiac entry. Crane participated in the Challenge as a contingency awards sponsor, and Gordon Johnstone, a key member of Crane’s R&D team, was on hand to see what interesting approaches the participants had come up with for their entries. The contest is based on an average of torque and horsepower over a 2500 to 6500 RPM range. The winners took home $82,500. Looks like Crane’s Quick-LiftÔ technology paid off!

Originally Posted by Vinci's Website

More On Why Our Unique New “Quick-Liftä” Rocker Arm Geometry Makes More HP!

There has been a great deal of dialog on several web forums pertaining to our "QUICK LIFT" camshaft lobes and rocker bodies. To set the record straight, this is what we have always maintained.

Here are a couple of questions about our rockers we would like to address.

Does the varying rocker ratio adversely affect spring harmonics?
Wouldn’t a fixed ratio rocker be easier on the valve train and cause fewer problems?
The first point that needs to be made in answering these questions is that there is no such thing as a constant ratio rocker arm unless you are talking about a very limited range of lift (.150” or less). This is because the pushrod seat end of the rocker and the valve tip end of the rocker are operating through two different distances and their ratio must constantly vary. Traditionally, most rockers have been designed to start the valve off the seat and return it to the seat slowly. (i.e. traditional SBC 1.5 ratio rockers started the valve off the seat at a ratio of 1.4 and did not get to a 1.5 ratio until .350” valve lift). This was because many OE valves were made in two pieces, and quick opening and closing rates could compromise the valve. The use of high quality, one-piece valves has made this a non-issue. Many performance aftermarket companies, including Crane, tried to develop rockers that were as close to constant ratio as possible. For instance, many 1.6 ratio rockers bring the valve off the seat at 1.62; by .250” valve lift, the ratio increases to 1.65 and by .550” valve lift, the ratio comes back to 1.61. Again, the ratio is varying due to the different length of operating arcs of the end of the rocker. Crane’s “Quick-Lift” design causes an “advertised” 1.6 ratio rocker to start the valve off the seat at a ratio of 1.72 and bring the ratio back to 1.60 by .250-.300” net valve lift. This ratio is then maintained through the rest of the lift profile until the valve is within .250-.300” from going back on the seat. It is then returned to the seat at a ratio of 1.72. This geometry is illustrated in this diagram.

Benefits of this geometry include more flow into the cylinder earlier in the cycle, quicker closing of the valve to trap cylinder pressure before combustion, more effective duration at .200” net valve lift while maintaining a relatively short seat-to-seat timing, and less valve spring seat pressure required because of the mechanical advantage of the higher seat ratio.

During development testing and now corroborated by more than two years of field-testing in competition, we have not seen any indication that the “Quick-Lift” geometry contributes to any additional valvetrain problems in any way. In fact, the evidence so far shows that our “Quick-Lift” Polymer Matrix Composite Bearing Shaft Mount Rockers actually seem to reduce harmonic issues in the valve train and extend spring life. At this time, we have no way of telling if this is the bearing construction or the geometry of the body or both! One other important feature of these rockers is the absence of needle bearings, which can break loose under extreme valve spring pressures and cause catastrophic engine problems. On average, we have eliminated 544 needle bearings from an engine with this design!!

“Quick-Lift” rocker body geometry causes the rocker arm to be a dynamic component in the opening and closing rate of the valve. Some people who don’t seem to understand this think it is “unnatural” to cause the valve to open faster than the cam lobe dictates, but OHC designs with finger followers have been doing it for years. After all, aren’t we interested in what the valve is doing relative to the piston position? Who cares how we get the valve there at the right time? The point is that “Quick-Lift” rocker geometry will broaden the torque curve (torque x RPM/ 5252 = HP!!!) of any cam you use it with. Our only warning: Super Stockers and others running extremely tight piston-to-valve clearance should check this with “Quick-Lift” rockers. Try ‘em; we know you’ll love ‘em!!

VHP and Crane Cams have been working with each other for many years. Together, we have strived to provide the very best products we can with the latest technology available. We think, we design, we manufacture, we test....then we market the product. It seems that there has been much confusion about Crane/Vinci "Quick-Lift" cam lobes and "Quick-Lift" rocker bodies. We claim that the use of the Quick-Lift lobes with the Quick-Lift rocker bodies results in "effective valve lift" durations @ .200" valve lift equal to most other cam/rocker combinations using cams with 4-8* more duration at .050" cam lift. This is the result of the Quick-Lift Rocker body design. We do not state that our cam lobes (by themselves) give this advantage. The same laws of physics that limit every other cam designer limit our cam lobe designs. We attribute the advantage in valve lift to the "translation" properties of the varying ratio design of our Quick-Lift rocker body design. If you don’t believe us, test any cam lobe (Crane, Comp, Cam Motion, etc.) with stock LS1 rockers. Install a dial indicator on the retainer and a degree wheel on the crank. Plot a lift vs. degrees of rotation curve. Then install the Crane LS1 1.7 rockers (with the pushrods in the Crane kit) and plot the same curve. Measure the duration at .200" net valve lift. The Crane rockers will definitely provide more duration at this checking point. The reason for this is that, contrary to popular belief, the stock LS1 rockers are only 1.7 ratio above .480" valve lift. They actually start the valve off the seat at a 1.54 ratio. What do you think that ratio does to a "super fast" cam lobe? Slows it down quite a bit? The Crane rockers, properly installed, bring the valve off the seat at 1.79. Doesn’t take a math wiz here to see what combination is going to get open quicker and longer!! If you really want to see something interesting, take two lobes that have identical .050" seat-to-seat timing, identical .200" lifter rise timing, but one provides .583" valve lift with 1.7 ratio and the other providing .551 lift with 1.7 ratio. Plot a lift vs. duration curve with any rocker you want (other than Crane) and measure the duration at .200" valve lift. Then do a plot of the .551 cam with 1.8 Crane rockers (this will net out .583 also) and measure the duration difference at .200" valve lift. You will be impressed by how much more this second plot gives over the first. It’s also quicker on the drag strip! We’ve done this. Every person reading these threads can do something like this.

Our point is that the only thing that counts is what happens at the valve and the overall rocker ratio is fundamental to this. Contrary to popular belief, there are no fixed ratio rockers on the market (this is because the valve tip end and pushrod seat end operate on two distinctly different arcs). This is why some rockers add power and some don’t. Crane/Vinci have elected to do extensive development with rockers as a supplement to the lobe. The quickest lobe in the world doesn’t mean diddly if you are using slow acting rockers! Like everything else, it’s the combination that counts. FYI, the higher opening and closing ratios actually allow lower seat pressures because the mechanical advantage of the ratio helps maintain proper lifter preload! Check it out. This isn’t smoke and mirrors; it’s applied geometry and it works!! Roger Vinci

http://www.vincihighperformance.com/...ometry%202.jpg

Originally Posted by mrr23

Originally Posted by GhostZ28

nice

(fyi to put in a direct image do this: [IMG] (web link to image) [/IMG] )