1.8 rockers?

[00buckshot]

cam in my sig, would you guys reccomend running 1.8s with it, heads have NOT been shaved and stock bottom end. Comp said that it would affect the ramp rate and it was up to me

[jetmech]

It shouldn't be a problem. Stock rocker ratio is only 1.7:1 anyways. I have a set of brand new 1.8:1 roller rockers if ur interested.

[Trevor]

any real gains from them? no clue about rockers

[00buckshot]

any real gains from them? no clue about rockers

I would hope to see a gain form the idea that it's a full roller rocker (over roller fulcrum stock), but it would take my lift over .610/.620

[skeet]

i've was told rockers arent really worth it, but then again i spent more dollars on mininumal horse power before, so said rockers are like 5-8 in gains, personally i dont think thats a bad thing. as for your lift , it depends on the springs you have, whats the lift on them? are they dual springs? i would hope so with the came youre running now, .610/620 isnt a bad lift at all i run 624 lift cam now

[Blown06]

Looks like you have the same cam as me. I run the Crane Gold Race 1.8 rockers on my truck. If my truck is running it is being pounded on and I've never had a problem with them. 7500 rpm burnouts and 7000 rpm shifts are the norm.

[collin]

Damn I remember when I put a cam in my 1998 SS and at the time a .575 lift was big and they reccomended not using 1.8 rockers. Things have come a long way. Just make sure your springs are up to it.

[ThumpinZ]

i'm not 100% sure about this but i believe like the open ratio on the 1.7's is like 1.62 or something if you go up a ratio the the open will increase a bit. the main goal of the 1.8's is basically to open and close the valves faster. I put a set of PRW 1.8's on my stock cam and enjoyed the lil extra and exageration of the lil stock thumper. 1.8's are GAIN approved in my book. I've set a few friends up and everyone seems to like them as well. The cranes are a little out of my price range next set will be the Harland Sharps, they have adjustables and stock 1.7 and 1.8 replacements " designed " to fit underneath the stock covers. I guess we'll see. Remember if you do go with a shaft mount you may need some head mods drill grind etc. The crane gold's are great but you need guide plates guides plates usually calls for a longer pushrod. If any of this info is wrong someone please correct me. I think if you go to www.vincihiperformance.com in their Q/A they have a whole break down of the rocker geometry. AND be sure to get the stud torque spec right! Don't listen to the idiots at PRW and hit 55 ft lb's like I did. Broke a stud pulled a head led to a new cam $$$$ cam was just because I wanted to, takin the head to a machine shop that was real.

[00buckshot]

I am running the revised 918's, supposed to be good to .625 lift, correct? Lift on exhaust would be .626 with 1.8 rockers

[ThumpinZ]

I'd think you'll be fine but I'm no valve train guru.

From Vinci
· Rocker Arm Geometry - If you’re looking for the most out of your valvetrain, you’ll need to look at your rocker arm geometry (Stud Mount Rockers). To fine tune your valvetrain, you are looking for a pushrod length that leaves the roller tip of the rocker towards the intake side of the valve tip, NOT dead center of the valve, when the valve is closed. You will see that the pushrod side of the rocker probably will have to drop down, and the roller tip will then pull back toward the intake side. This will be achieved with shorter length pushrods and will help you get better power because you will be opening the valve quicker. This will also leave the highest spring pressure load occurring with the rocker tip at the center of the valve at full lift, not off towards the exhaust side. Just be careful not to get into contact with the top of the retainer and the underside of the rocker arms when setting up this geometry.

ROCKER RATIO

Good Stuff Happens When You Increase Your Rocker Ratio - When changing rocker arm ratios on your engine to a higher ratio, not only does the gross valve lift increase, but the duration at the valve in the higher lift ranges also grows. Aside from the usual valve spring/retainer travel considerations, your piston-to-valve clearances will now be reduced. Please check and make certain that you have sufficient piston-to-valve clearance before starting your engine after increasing your rocker arm ratio. Don’t guess at this - check it!


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.

Chevy High-Performance Magazine LS1 Project Truck Gains Average 25 HP

And 20 Ft. Lbs. Torque By Switching To Crane Gold-Race Rockers!

It’s well known that switching from stock rockers to a full-roller, longer-ratio performance style rocker can deliver gains in both horsepower and torque. CHEVY HIGH PERFORMANCE MAGAZINE Editor Ro McGonegal volunteered his “Red Dog Plan,” 2003 Chevy truck to find out how much. After obtaining the Crane Gold-Race aluminum rocker kit (Part No. 144759-16, includes 1.8:1 rockers, lock nuts, screw-in studs, pushrod guideplates and stiffer, heat-treated chromemoly pushrods), Ro took the truck to Vinci High-Performance (105 Candace Drive, Unit 101, Maitland, FL 32751, 407/478-8388) for installation and comparative dyno testing. The guys at Vinci also recommended replacing the stock LS1 “beehive” design valve springs with Crane dual springs and retainers (Part No.’s 144832-16 and 144661-16). The Crane springs provide needed additional spring travel and pressure, (110 lbs. seat pressure, 350 lbs. open load) and they eliminate the operating “noise” commonly produced by beehive design springs. This noise triggers the factory “knock sensor”, which retards spark advance, dramatically reducing power and torque output! The “longer” rocker ratio increases gross valve lift, and the exclusive “Quick-Lift™” design of the Gold-Race rockers opens the valve quicker, beginning flow earlier. On Vinci’s chassis dyno, the truck recorded “before” average numbers of 200.7 hp and 245.7 lbs. ft. torque. After installation of the Crane parts, those numbers jumped to 219.9 hp and 266.5 lbs. ft. torque, an average increase of 20 hp and 20 lbs. ft. torque over the stock rockers and springs! (Max torque came at 4,000 rpm and was 299.6 lbs. ft. Max hp was 255.9, and that was recorded at 4,900 rpm! That means the truck kept on pulling at a higher rpm than stock!) Ro was especially impressed after he felt the very notable “kick in the butt” delivered by the added torque! Whether it’s a full-sized Chevy or GMC truck, F-Body Camaro or Firebird or Corvette, GM LS series engines respond tremendously to the power increases delivered by Crane rockers, cams, valve train products, and the new Power-Tuner to fine-tune for max performance. Our thanks go to CHEVY HIGH PERFORMANCE MAGAZINE Editor Ro McGonegal and Group Publisher Tom Voegele for giving our products a try. The complete story appears in the CHP August Issue, pages 56-58, and on-line at: www.chevyhiperformance.com

New! Gold-Race Rockers For Air Flow Research “Mongoose” LS1 Cylinder Heads!
Due to the increasing popularity of the Air Flow Research Mongoose series cylinder heads for the LS1 series of Chevrolet V-8 engines, we will now introduce two new Gold Race aluminum roller-tip needle bearing rocker arm kits for these applications, including all installation hardware. This is because the AFR heads require pushrods that are .100” longer than those that come in our 144750-16 and 144759-16 kits.

New part number 144750AF-16 will be the 1.7:1 ratio kit, while 144759AF-16 will be the 1.8:1 ratio kit. These kits contain a full set of rocker arms and all of the installation components required, such as pushrod guideplates, rocker arm studs, adjusting nuts, etc. as our other popular LS1 kits. Current suggested retail price for either kit is $836.00. Purchase them now from VHP for only $699.00.


VALVE TRAIN TIPS

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


Here is the link to that info has some illustrations. http://www.vincihiperformance.com/LS...20.HTML#Rocker Arm Geometry

I believe there is also a break down on Hardland Sharps page diagrams etc. I recently found a really good right up and diagrams if there not on Harland I'll look a bit later today and see if i can find it.

Are you running thinner head gaskets? if so and you went with rollers you might not have change the pr's but double check the length