mrr23

iTrader: (3)

ask me and i'll tell you yes. after all, the vinci/crane rockers work well enough to add power to a stock cam. things you need to look out for will be piston to valve clearance. the vinci/crane rockers work much differently than most other rockers on the market. most rockers start off LESS than the rated ratio. then move towards the rated ratio as you get closer to peak lift. the vinci/crane do the opposite. the 1.8 rockers, for instance, start off at 1.89 until about .250-.300 valve lift. then start converting to 1.82 by max lift. vinci tech and tune page this, in effect, changes the valve duration. popping the valve open sooner and faster may create a piston to valve interference in some cases. i don't see it happening in your case.

no tuning is required. when i did the rockers on the wife's car, that was without any tuning. same for the 5.3L truck they did it on.

ss1

iTrader: (32)

Thanks for the help If anybody else would like to chime in, it would be appreciated.

badmfkr

iTrader: (4)

I've read that the Crane varible ratio rockers are extremely hard on valve springs plus high cost being forced to purchase another set of push rods Crane is forcing me to buy the Harlan Sharp 1.8 rockers.

I think the HP rockers are better than SLP or Comp. because of the roller tips,plus they are priced resomably.

Will the HP 1.8 rockers require pushrod guides?

Thanks

mrr23

iTrader: (3)

no harder than if you built the same ramp rate into the cam that would be happening at the valve. in fact, i would venture to say less. with the advantage of higher ratio rocker, it takes less valve spring seat pressure. also, i have mentioned the lifters, pushrods, and rockers are moving slower on the cam side. so, the spring has less inertia to have to control speed wise.

the vinci/crane rocker kit consists of rockers, posilocks, shorter chrome-moly pushrods, guideplates and screw-in-studs. one of the benefits of having shorter pushrods is less flex. besides them being chrome-moly. so, for first time buyers, they are really only buying two additional parts, the guideplates and screw-in-studs.

after all, if you are buying aftermarket rockers, you will be getting the posilocks (except for the upgraded factory rockers that nasty perforance does) and should be buying stronger pushrods as well.

MadSeason

Hey guys, question for you. Do the stock rocker ratio with the Crane Gold Race LS1/6 1.7:1 Full Roller Aluminum Rockers have any benefit over the stock rockers? I have the money, and if the mod is good for something I might as well go for it. -Ed

LETHL_SS

iTrader: (21)

FWIW, I'm running Crane Gold 1.8's with a 242/250 .580/.580 109LSA cam with no issues at all. Yes my pistons are flycut though.

Here is my most receint Dyno with the current setup.



Here are the pistons and rockers.

4mula

try running a simple 224 cam with 581 lift on it and dont fly cut, see what happens

mrr23

iTrader: (3)

ok, just one of the two things i had previously stated. you can run them so long as you have proper piston to valve clearance and proper spring control.

mrr23

iTrader: (3)

now isn't that interesting. the biggest concern of most on this board is a certain dip in the graph in the 6200 to 6500 range. most keep saying it's valve float. amazing you don't have it. probably because you took the time to set up everything correctly. the one thing that people have been saying to do. instead of just saying it's valve float and throw them away. thanks for that graph.

mrr23

iTrader: (3)

very much so. vinci has this exact question answered on their tech and tuning page . right about in the middle of the page.

cliff notes:

stock rockers come off the seat at 1.54 and reach the advertised 1.7 at almost full lift. on the way back down, they convert back to 1.54. the vinci/crane 1.7 rockers actually start off at 1.79. then, by .250-.300 valve lift, they start converting to 1.72. then on the way back down. start converting back to 1.79.

98_Formula

iTrader: (15)

^^ would those be safe to use with a high lift cam? like the ms3 or g5x4

nokeman

iTrader: (30)

So when is a good time to upgrade the rockers? I know this probably isnt the best source of info but, horsepower tv upgraded the rockers on thier ls1 project didnt they? Either way, they always say roller rockers are much better than standard rockers. Is this completely true or is the difference so small it doesnt even matter?

MadSeason

Nice Read, Thanks

mrr23

iTrader: (3)

my opinion is this: so long as you have proper piston to valve clearance and proper valve spring control, they will work.

mrr23

iTrader: (3)

this is one of those opinion questions. there are people running 9s with stock rockers. and some running 9s with the vinci/crane rockers. you'll get answers like you don't need them unless you are turning 7000+ rpms. and you'll get my answer of if you are trying to extract the most that you can, then get them. i've been running them with a stock cam for over a year. i like the added power without the annoyance of a larger cam. (well, the wife does)

is 15-20 rwhp a small difference?

mrr23

iTrader: (3)

anytime.

vettenuts

iTrader: (4)

Very nice . How much lifter preload are you running? Also, what is the rest of your setup (springs, lifters, etc.)

NemeSS

iTrader: (127)

just a thought
but if anyone is so interested in using 1.8 rockers
y not just adapt some exhaust ls7 when they come out
i think they will be significantly lower priced than aftermarket
this is what i plan on doing with a motor im building
the cam is a 02 z06 204/218 .550/.550@117.5 lsa
with 1.8 rockers it should increase 1-2*more and .582 lift theoretically

LETHL_SS

iTrader: (21)

I'm not running any shims and the preload is set at .075". I'm still using stock lifters, have the crane dual valve springs, and 7.200" moly pushrods. The rest of the bottom end is stock but with ARP bolts throughout.

vettenuts

iTrader: (4)

Is that preload at the pushrod or the adjustment nut? (How many turns?)