Anyone know at what rpm hydrualic lifters start to 'float'.
Mine seem to start about 6500 rpm.

 

It's the springs that cause valve float. I don't know what you are talking about. You'd have to give us a LOT more information on what your setup is to help you out.

 

Excuse me for my ignorance. I am relatively new to LS1 motors. I am just trying to determine the rpm range of my motor.

I've had some experience in the past with the first generation small block chevy. The problem on those motors was that the hydraulic lifter would 'float' at about 6500 rpm. In other words, at high rpm, the orifices within the lifter that allowed the oil to circulate back and forth (hence, hydraulic lifter) were not large enough to allow the fluid too pass under high rpm (6500+). The lifter would then 'float'. This was one of the main drivers for going to a solid cam since it allowed you to extend your rpm range.

The only reason why I am asking is because I may want to go to a solid roller cam someday, but not sure if I can justify it just now.

I've already have the heavy duty springs and retainers.

 

I think the term you want to use to describe what goes on at high rpm in hydraulic lifters is "pump-up". Sorry, I don't know the answer to your question though. But I do rev to near 6500 rpm on stock lifters without noticing any problems.

 

Valves float not lifters.
Incorrect valvetrain geometry / spring weakness will cause that.
A lifter pump up is when you have incorrect preload on the lifters, then they pump up at higher rpm, which will cause their failure.

 

I didn't mean to be rude if that is how you took it. You can run the stock lifters (with everything else being setup correctly; springs, retainers etc.) to 7000+ Thing is does your cam make power up there. If it doesn't there is no need to rev that high.

 

Valve float on stock springs can occur as soon as 6300 rpm.

 

Cam is a G5 cam: http://www.lmperformance.com/4934/1.html

Springs are the comp cam valve springs.

I might change out the cam later for a soild roller w/ alittle more lift/duration.

No offense taken

 

Dude no offense, but I do not think you understand what it means to go solid roller.

 

I thought the main reason for going solid lifter was to run ultra heavy springs that would normally crush a hydraulic lifter. That lets you run a huge lift cam and spin very quickly without worrying about valve float.

 

Trust me, I know exactly what it means to go solid roller

 

There's more to a solid roller setup than just changing cams to a "solid roller" cam. You have to do a lot of work to the valvetrain.

There is more than one type of spring that comp makes. Some are strong, some aren't. Which ones do you have?

EDIT: Just to let you know, I am running quite a bit bigger cam than that and I don't have any valve float even at 6800

 

Agreed....

 

Source: http://www.amotion.com/tech/camtalk.html

HYDRAULIC lifters use the engine's oiling system to automatially adjust the valve lash (clearance) to zero. They are the most common type of flat tappet cams and lifters for street use. Hydraulic cams can use any one of the three types of these oil filled lifters.
Stock type hydraulic lifters are quiet running and require little or no adjustment after installation but are limited in performance to about 5500 rpm. The ANTI-PUMPUP lifter is a type of hydraulic lifter that will rev higher but requires adjustable valve train components. VARIABLE (also known as Vari-Duration) hydraulic lifters are the next step up from anti-pumpup lifters. They improve low-end power and permit higher rpm use without the requirement of valve adjustment. RHOADS is the original manufacturer of variable hydraulic lifters and still makes the most effective ones.

MECHANICAL or SOLID cams use a solid or oil control flat tappet (lifter) which requires regular valve adjustment. Some performance shops prefer solid lifters, even for street use, because they can adjust the way a cam will perform to a limited extent by changing the amount of lash (clearance) in the valve train. Decreasing the lash increases the duration and lift, increasing the lash decreases the duration and lift. For race use solid lifters will perform up to about 8500 rpm.
MUSHROOM lifter cams use solid lifters that look similar to an upside-down mushroom. The base of the lifter (where it contacts the cam lobe) is wider than the body of the lifter. These are used mostly on oval tracks when roller lifters aren't allowed. Block machining at the bottom of the lifter bores is required.

ROLLER cams, as the name implies, use a lifter with a roller as the surface that follows the cam lobe. The roller surface allows very precise valve movement, as well as reduced friction, permitting a much wider operating range than is available with a flat tappet cam. Hydraulic roller lifters are common in late model engines and a variety of performance cams are available. They are as quiet and maintainance free as flat hydraulic lifters. Solid roller lifters are used mostly in highly modified race engines although there are a couple available for "pro street" applications. For maximum rpm use a solid roller design is definitely the best choice.

 

I meant understand the implications on your LS1.

G5-112 G5 224/230 Duration & 581/572 Lift at 112 Lsa
G5-114 G5 224/230 Duration & 581/572 Lift at 114 Lsa.
G5-X1-112 G5X1 228/232 Duration & 588/574 Lift at 112 Lsa
G5-X1-114 G5X1 228/232 Duration & 588/574 Lift at 114 Lsa
G5-X2-112 G5X2 232/240 Duration & 595/608 Lift at 112 Lsa
G5-X2-114 G5X2 232/240 Duration & 595/608 Lift at 114 Lsa
G5-X3-112 G5X3 2??/2?? Duration & 600/610 Lift at 112 Lsa
G5-X3-114 G5X3 2??/2?? Duration & 600/610 Lift at 114 Lsa

as you can see, your cam is "small" compared to the bigger 3 other hydraulic ones the also carry, and now they even have an G5X4

You just do not go solid roller for just a "little more lift"

 

All of us?? don't think so LOL

 

Please point out my "misconception", I want to learn

 

Yeah, you're absolutely right, I didn't express myself correctly.
I meant incorrect high preload (too long p-rod or too tight adjustables) will put too much stress on the lifter internals and when they pump up, they fail. sorry about that.

 

Wait a minute, valve float is basically when the valve has too much inertia and loses contact with the lifter. As stated before, the causes can be several things (springs, cam geometry, valve size, etc.)

 

Yes, UnnafiliatedRacing was correcting my interpretation of "pump up"
and what I meant was