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. |
Describe the rest of the valvetrain - i.e. what valve springs, rockers, etc. |
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 |
Easiest first step would be to switch back to stock rockers. After that I'd pull a couple springs and check pressures |
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 |
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 |
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 . |
Call PAC and give them your cam specs. They can get you a quality spring with the pressure you need |
Springs or lifters. Maybe a combo of both. |
The lifters are like new only have maybe 200 miles on them |
Fuel pressure at WOT? Injector size? |
A very erratic power band is valve float 90% of the time. |
It has 30lb injectors , what does erratic power band mean ? |
Your power band line on the dyno gets very jagged just befor you lose your power. |
I'm guessing you need new springs, AND shimmed to within .050 of coil bind. |
I think I'm just gunna get some new springs the valvtrain seems a tiny bit noisy also |
|
Posted dyno graph please tell if it looks ok ? |
Originally Posted by dr_whigham
(Post 16468813)
I'm guessing you need new springs, AND shimmed to within .050 of coil bind. |
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. |
| All times are GMT -5. The time now is 07:54 PM. |
© 2026 MH Sub I, LLC dba Internet Brands