Do I have valve float or no? Dyno graph inside, need opinions
05-07-2011, 12:12 PM
#2
That isn't necessarily from valve float & probably is not. The float would be seen higher in the RPM range, rather than through the entire curve. That looks more like the normal electrical noise or scaling that's seen on dyno sheets.
That many miles could use a spring upgrade though. General rule of thumb is change @ 20K miles, but depends on cam lift & duration as much as it does the spring design. Have seen guys run to 50K without any float. Again, it all depends. If it were mine, I would change the springs.
That many miles could use a spring upgrade though. General rule of thumb is change @ 20K miles, but depends on cam lift & duration as much as it does the spring design. Have seen guys run to 50K without any float. Again, it all depends. If it were mine, I would change the springs.
05-07-2011, 01:45 PM
#3
^^yeah, I'm really getting worried about it. I'll change em for sure this year and I'll do the rocker upgrade while at it. But lifters are bothering me too, but I'm not sure I wanna pull the head just for that..
Thanks for looking at my graph!
Thanks for looking at my graph!
05-07-2011, 01:56 PM
#4
No, because valve float usually doesn't recover.
Looks like a normal graph to me, with maybe some tuning that needs smoothing out. Definitely need to change springs now if you've got that many miles/time on them. I generally recommend spring changes every 20K.
Looks like a normal graph to me, with maybe some tuning that needs smoothing out. Definitely need to change springs now if you've got that many miles/time on them. I generally recommend spring changes every 20K.
05-07-2011, 06:20 PM
#6
i know the "smoothing" on the dyno graph makes a difference on how the curves look. 1 to 5 I think, with 5 being the highest. I just looked at my graph that has the smoothing set to 5 like yours, and mine looks a considerable amount ummm well smoother lol. My springs being newish i would agree its time for a spring change
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05-08-2011, 09:50 AM
#10
If the camshaft is below .620 lift, go with a PSI 1511 endurance spring. Their quality control is second to NONE, it's not a big heavy spring that robs power, and they have a zero failure rate. Only $190 too. 
FWIW, I've shimmed the PSI's to work with a .625 lift LSL lobe camshaft and they're still working perfectly 15K later. Great spring.
FWIW, I've shimmed the PSI's to work with a .625 lift LSL lobe camshaft and they're still working perfectly 15K later. Great spring.
05-26-2011, 08:51 AM
#12
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Hey poeple , I just wanted to clear the stiffer spring robbing power myth . Stiffer springs do wear cam lobes harder and lifters ........etc but rob almost zero from the overall power if any at all . While 1 spring is being collapsed another is pushing opposite with equal force on the cam which transfers to the 1 being collapsed thus equalizing or canceling 1 another .
