Symptoms of valve float

[Clutch GSX]

What are the symptoms of valve float? Would I even know if I was floating valves?

 

[95blackGsTurbo]

Unless you are revving stock springs to 8500 this is a non issue. Symptoms are valve to piston contact.

 

[Clutch GSX]

I have upgraded everything but I had my springs measured and they seem to be seriously lacking in pressure compared to other after market springs. They are not stock springs. I have HKS 272 cams and will be revving to around 8000RPM.

Is there any way to tell if the valve is going to float without just running it and hoping for the best? I'd hate to risk bending valves on my brand new build

 

[95blackGsTurbo]

Compare the springs pressure to what it was suppsed to have new. What readings are you getting? What kind of springs?

 

[LiquidX]

What brand and what are the pressure numbers on the springs? I doubt you'll have problems unless they are just slightly better than OEM springs. I even think OEM springs have gone to 8k (not safe but still have).

 

[Clutch GSX]

They are clevite springs with a custom retainer. Here are the specs:

1.750" - 48
1.700" - 55
1.650" - 62
1.600" - 70
1.550" - 78
1.500" - 87
1.450" - 95
1.400" - 103
1.350" - 111
1.300" - 120
1.250" - 131
1.200" - 141
1.150" - 152
1.100" - 163
1.050" - 176
1.000" - CB

Thanks for the help guys.

 

[BogusSVO]

well do you have the part number of the springs?
what is the installed height that is used on your head?

here is some spring info I have gathered up...
http://www.dsmtuners.com/forums/newbie-forum/341209-4g63t-valve-spring-info.html

 

[Clutch GSX]

I don't have the part number. The hieght is a little higher than stock since I had a valve job.

 

[BogusSVO]

with out knowing what the installed height is of the spring, on each valve you may float a valve on one but not the next....

 

[herms99gst]

my buddy has a stang that had the valves float. Only he acct. ran his. When he launched the car it pulled crazzy hard, but as soon as he started hitting hire rpms it just died. His valves never contacted the piston though...i dont know if this is due to more valve to piston clearance or not??

 

[dan catalyst]

you need to measure the installed height of your springs and add shims to get it back to stock height or your seat pressure will be low.open pressure will be about the same,so dont get the two terms confused. shims are a must after a valve job.the installed height micrometer is only $30 or so from summit or ebay.

 

[Clutch GSX]

The head is at the machine shop. I'll have them measure it and get back to you guys. Thanks for the help.