LS1TECH - Camaro and Firebird Forum Discussion

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-   -   I think I'm having valve float help! (https://ls1tech.com/forums/generation-iii-internal-engine/1560607-i-think-im-having-valve-float-help.html)

Luke1834 Jun 28, 2012 05:39 PM

I think I'm having valve float help!
 
I have a forged bottom end with 232/236 114lsa and .615 lift cam with patriot ls6 heads when my car got to 5800 Rpms on the dyno it isntantly stoped making power.

Darkman Jun 28, 2012 06:30 PM

Describe the rest of the valvetrain - i.e. what valve springs, rockers, etc.

Luke1834 Jun 28, 2012 07:47 PM

It's got ls7 lifters comp gold 1.7 rockers hardened pushrods and it has dual spring from
The previous owner if I had to guess there probably patriot (patriot heads) it's the only used thing I used when I built this motor besides the crank . I'll post the dyno graph in a little basically climbs to 400hp as Soon as it hits 5800rpm it levels out and the line is al squiggly lol

outkast6991 Jun 28, 2012 07:55 PM

Easiest first step would be to switch back to stock rockers. After that I'd pull a couple springs and check pressures

Luke1834 Jun 28, 2012 08:10 PM

why would i switch back to stock rockers? I had stock ones on there when it was dyno. then i put roller rockers on because the bearings were going and its exactly the same just quieter

outkast6991 Jun 28, 2012 08:35 PM

Didn't know you had the float on stockers. Aftermarket rockers are known to be heavy over the nose which will induce float. Guess its time to pull some springs

Luke1834 Jun 28, 2012 09:44 PM

what new springs would you guys recommend this cam should make power to 6500 rpms and with the forged bottom end i wanna take it that high .

outkast6991 Jun 28, 2012 09:47 PM

Call PAC and give them your cam specs. They can get you a quality spring with the pressure you need

Havoc40 Jun 28, 2012 11:51 PM

Springs or lifters. Maybe a combo of both.

Luke1834 Jun 29, 2012 09:14 AM

The lifters are like new only have maybe 200 miles on them

KRAZY K 2000 TA Jun 29, 2012 10:15 AM

Fuel pressure at WOT? Injector size?

TurboBuick6 Jun 29, 2012 10:19 AM

A very erratic power band is valve float 90% of the time.

Luke1834 Jun 29, 2012 10:39 AM

It has 30lb injectors , what does erratic power band mean ?

TurboBuick6 Jun 29, 2012 11:01 AM

Your power band line on the dyno gets very jagged just befor you lose your power.

dr_whigham Jun 29, 2012 02:15 PM

I'm guessing you need new springs, AND shimmed to within .050 of coil bind.

Luke1834 Jun 29, 2012 02:39 PM

I think I'm just gunna get some new springs the valvtrain seems a tiny bit noisy also

Luke1834 Jun 29, 2012 04:55 PM

http://i46.tinypic.com/t53hvq.jpg


that is the dyne 5 days before i switched to turbo 400

Luke1834 Jun 29, 2012 11:27 PM

Posted dyno graph please tell if it looks ok ?

LilJayV10 Jul 1, 2012 02:02 PM


Originally Posted by dr_whigham (Post 16468813)
I'm guessing you need new springs, AND shimmed to within .050 of coil bind.

This. I was going to ask what your spring height is set at.

LilJayV10 Jul 1, 2012 02:03 PM

Normally when you have valve float there's a dip at the top end and then it nose dives off. It doesn't appear that yours is doing that. However your tq curve seems to be a little wavy. The local machine shop set my heads up wrong and I had horrible valve float. My dyno graph was really jagged and then dropped off.


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