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Rocker arm QuesTionS ??? new to LS1

This is a discussion on Rocker arm QuesTionS ??? new to LS1 within the Internal Engine forums, part of the LSx Technical Help Section category; O.K. so I have .496/1.7X1.85= .539...

  1. #41
    2004 HEAD/CAM CTS-V 9t8z28's Avatar
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    O.K. so I have .496/1.7X1.85= .539

  2. #42
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    Iam about ready to put my 481 bbc in it lol.

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    i have a question! i really have never messed around too much with going over what lift a spring can take, but i just bought a used ls6 cam and springs, but the springs are the yellow ones, and only designd to take 550 lift, by me switching to 1.8's im right at that, will i break a spring running it this close to its limit?

    thanks, my buddy says just put it in theres only one way to find out. lol

  4. #44
    Senior Member mrr23's Avatar
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    Quote Originally Posted by camarojunky74 View Post
    i have a question! i really have never messed around too much with going over what lift a spring can take, but i just bought a used ls6 cam and springs, but the springs are the yellow ones, and only designd to take 550 lift, by me switching to 1.8's im right at that, will i break a spring running it this close to its limit?

    thanks, my buddy says just put it in theres only one way to find out. lol
    you are pushing the springs to their reported limits. they'll hold, just don't know for how long.

  5. #45
    Senior Member mrr23's Avatar
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    Quote Originally Posted by 9t8z28 View Post
    Yeah, I already read it. I don't see the difference from quick lift rockers and increased ratio rockers?
    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.

    The Crane rockers, properly installed, bring the valve off the seat at 1.79.
    the SLP rockers are designed just like the stock LS series of rockers. so, the 1.85 rockers still aren't coming off the seat at the advertised 1.85 ratio. and most other aftermarkets follow this same pattern of design. and this is the reason why, with most aftermarket rockers, you only see a small amount of hp gain.

    scroll down on this page and read some more of the quick lift design.
    http://vincihighperformance.com/LS1%...%20PARENT.HTML

    The end effect is this: a 1.6 ratio “ACCELERATED LIFT” rocker arm actually starts opening the valve at a ratio of 1.7. As the valve opens, the rocker ratio decreases to the 1.6 advertised ratio (this occurs at about .250” - .300” valve lift) and then maintains the 1.6 ratio through the rest of the lift cycle until it starts back on the seat. It goes back on the seat at a 1.7 ratio. This new geometry provides increased airflow earlier in the lift cycle and maintains it longer into the closing event. More flow equals more power! There are additional benefits. The “ACCELERATED LIFT” design applied to computer managed engines means that short seat-to-seat timing can be maintained to provide high vacuum at idle and low speed, but duration at .100”, .200” etc. is equal to camshafts having .050 durations 8 to 10 degrees bigger. This means great power increases and ease of tuning the engine management system.
    Last edited by mrr23; 08-07-2007 at 04:35 PM.

  6. #46
    Senior Member mrr23's Avatar
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    more reading on this. no other rocker, that i'm aware of, has been banned from racing. that means something, when the powers to be make that kind of decision over one part of an engine.

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

    crane cams newsletter mar 2006

    Crane Gold RaceŽ Rocker Arms Dominate Engine Masters Challenge

    crane cams newsletter oct 2005

    Chevy High-Performance Magazine LS1 Project Truck Gains Average 20 HP

  7. #47
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    good write up mrr23

  8. #48
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    Terras, harland, or quick-lifts ?

    Wheres the cheapest place to buy them?

  9. #49
    Senior Member camarojunky74's Avatar
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    texas speed or summit, summit does price matching on anything...

  10. #50
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    I thought about it and I dont think Iam going to do anything else to my car but put some slp exhaust on it. My rockers are spitting out the bearings. I need to put some new rockers on it. So the 1:8 quick-lifts would be the best hp increase?

    Do newer OEM rockers have a retainer on the bearings to keep them from coming out? If so I mite just put some stock ones back on it. I just dont want to change them again.

    thanks

  11. #51
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    I have not seen a new GM rocker, but you would think since GM was paying for the carnage when it occurred they would have updated the design to prevent it from happening. That said, I removed rockers from an 04 the other day and could not tell any difference from my 02's.

  12. #52
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    You think GM would put out a recall on them.

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