Generation III Internal Engine 1997-2006 LS1 | LS6
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Old 07-30-2008, 08:22 PM
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Default valve float

can you actually FEEL valve float
Old 07-30-2008, 08:26 PM
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i didnt "feel" anything, i just heard my car tickin and running like crap. tore it apart and noticed i bent a push rod. not fun.
Old 07-30-2008, 08:48 PM
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loss of power in top end is how you would feel it normally.
Old 07-30-2008, 08:54 PM
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a hah, thats wat i feel

i huge loss power from 5200 to 6000 ****
and i mean GIGANTIC power loss

it falls flat in its place and i "feel" the valve float. i guess
Old 07-30-2008, 09:06 PM
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Yup. Sounds like it or wrong length pushrods, or valves not seating all the way. Do a compression test.
Old 07-30-2008, 09:15 PM
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completely stock ls1 internals with only longtubes ory and corsa cat back. my numbers are in my sig

i do shift at around 5800 rpm when i race

rev limiter raised to 6200

how do i do the test??
Old 07-30-2008, 09:19 PM
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You should not be geting valve float with stock cam. How did you make 370rwhp with just an exhaust system?
Old 07-30-2008, 09:38 PM
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it did what it did, the dyno graph is on the links just so you know i am not bs'ing



then, if i shouldnt,then what am i feeling, i am going to do a compression test ASAP, but dont know how, where do i get it
Old 07-30-2008, 09:41 PM
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The stock valvetrain was never designed to rev that high so YES you can have valve float with a stock cam.
Old 07-30-2008, 10:27 PM
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Originally Posted by socmguy
The stock valvetrain was never designed to rev that high so YES you can have valve float with a stock cam.
what springs do you recommend for revs all the way up to 6500

i might just buy the stg 2.5 5.3 heads form tsp

http://www.texas-speed.com/shop/item...id=84&catid=20
Old 07-30-2008, 11:52 PM
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Old 07-30-2008, 11:56 PM
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Just order some hardened pushrods... I'll help you throw those in first (because I'll bet money you simply missed a shift and bent some rods) and then we'll go from there...
Old 07-30-2008, 11:59 PM
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Originally Posted by 6LITEREATER
Just order some hardened pushrods... I'll help you throw those in first (because I'll bet money you simply missed a shift and bent some rods) and then we'll go from there...
yeah, i guess

hopefully i can find some 918 springs and seat, etc and slap those one also, you gonna have to help me with that, do they come in the package or do i have to buy the springs,seat and all that crap separately
Old 07-31-2008, 12:03 AM
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Originally Posted by ReFtheMC

Old 07-31-2008, 04:53 AM
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6200 isnt that high for an ls1. I spin my stock internal 160k lt1 to 6000rpm. I think its a worn spring or two or broken pushrod. If you're losing power down at 5200 rpm. Ever missshifted it?
Old 07-31-2008, 05:43 AM
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its to easy to check a push rod. just take off the coil packs, valve covers, then rocker arms. then start pulling them out, lay them on a flat glass surface and roll them to see if they are strait.
Old 07-31-2008, 05:59 AM
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check your pushrods you shouldn't be getting valve float. A stock cammed Ls1 only makes power to about 55-5600rpm and it falls off from there, as thats why you are shifting at 5800rpm as the next gear drops it right damn near the tq and hp curves
Old 07-31-2008, 02:46 PM
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Go with PRC duals and do it once.
Old 07-31-2008, 03:44 PM
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When I was stock my WOT shift was 6k with no valve float. I bet worn springs too. How many miles?

You will hear it ticking if you have bent pushrods bad enough to make it lose that much power.

If your gonna do springs I would go PAC. I still don't trust 918's. Search it and you will find they wrecked a lot of motors.
Old 07-31-2008, 03:50 PM
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Thats funny that you mention that your power drops off hard at 5200 rpms....well its no surprise to me because the stock cam is supposed to have peak power at 5200 rpms!!! If you look at a stock graph, you'll see that the power drops off hard after 5200 rpms, its cam limited, not your springs or pushrods, although it wouldn't hurt to check them.



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