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HEMI way or no way
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Discussion Starter · #1 ·
Had a few questions:

- What rpm will the valves start floating on a HEMI ?
- Upgrading the springs, pushrods, etc will safely take you to what rpm?
- I presume the stock hydraulic lifters will be the weak point in the chain, are there ANY after market lifters available? Preferably SOLID...but i know then you are in the game of feeler guages for correct setup.

What sparks this conversation you might add? Well I have been abusing the beast the past few days, and this afternoon...revved her up, broke traction all the way through 1st gear....got up to 6200 rpms....with a stock drivetrain....told a good friend of mine here at work ( a fellow mechanical engineer who has a 2000 5.9 Ram).....and he immediately drops a comment..."Floating them valves!!" I told him about my 6200 rev limiter and my 1-2 shift that starts @ 5950 rpm with the superchips....he was very convinced that I would have been floating at that rpm....what do you all think or know about valve float?
 

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Inertia ROCKS!!!!
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Don't worry about it I really don't think you'll have valve float at 6200, but if you are worried then the Transgo shift kit will make your trans shift exactly where you set it. So if you set it at 5950, then it starts and stops at 5950, and a couple hundred above stock won't hurt anything. There are no aftermarket lifters that I know of for our trucks and that Manley setup will easily handle 6200 RPM's. Solid lifters are a huge noisey PITA.....you wouldn't want those if they were available, at least they were on any old Mopar I had them on. Relax bro...I'm ordering my stuff today as soon as I get a hold of Bob...WOO HOO!!!
 

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Inertia ROCKS!!!!
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Also when I had my 5.9 in my Dak that thing would float the valves at something like 5200 or 5500...sounded god awful until I replaced the springs. The springs are what usually cause valve float. This guy that said this probably has no experience with the high RPM Hemi!!!
 

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Valdez Racing Team
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...how can you tell if valves float?...is it a sound it makes?...reason Im askin, I just changed to a 6.1 cam, when im accelerating I could feel the pull until the rpm's get high where i get a whaawhaa sound and then i have to back off a little....
 

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HEMI way or no way
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Discussion Starter · #5 ·
yeah he is a 5.9 guy ;)

i wasnt so much worried as i am wanting to learn more about what that engine goes through!

Bob is ready and waiting for you.....my current status is:
- Arc-1 arriving 10/2
- Wideband arriving 10/3
- No word on cam yet, but will know as soon as Bob does
- Pushrods, retainers are out about 3 weeks

Now thinking about if I want black powdercoated valve covers! will the madness ever end?
 

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HEMI way or no way
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Discussion Starter · #6 ·
chefred112 said:
...how can you tell if valves float?...is it a sound it makes?...reason Im askin, I just changed to a 6.1 cam, when im accelerating I could feel the pull until the rpm's get high where i get a whaawhaa sound and then i have to back off a little....
I couldnt answer that bro....but im sure someone can advise
 

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Fred, Play with your shift points and get it where it feels good. how much did the cam improve things?
 

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Inertia ROCKS!!!!
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chefred112 said:
...how can you tell if valves float?...is it a sound it makes?...reason Im askin, I just changed to a 6.1 cam, when im accelerating I could feel the pull until the rpm's get high where i get a whaawhaa sound and then i have to back off a little....
A valve float noise is a very loud metallic sound at high RPM's coming from the engine, not to be confused with a deep rod knock sound which you would probably hear all the time and it would get worse the higher the RPM's. What you're describing sounds like it could be but a 6.1 cam and stock springs at anything below 6200 should be totally fine, you may have a collapsed lifter.....can you get a sound clip of it?
 

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MrDestinE
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skaarew said:
Had a few questions:

- What rpm will the valves start floating on a HEMI ?
- Upgrading the springs, pushrods, etc will safely take you to what rpm?
- I presume the stock hydraulic lifters will be the weak point in the chain, are there ANY after market lifters available? Preferably SOLID...but i know then you are in the game of feeler guages for correct setup.

What sparks this conversation you might add? Well I have been abusing the beast the past few days, and this afternoon...revved her up, broke traction all the way through 1st gear....got up to 6200 rpms....with a stock drivetrain....told a good friend of mine here at work ( a fellow mechanical engineer who has a 2000 5.9 Ram).....and he immediately drops a comment..."Floating them valves!!" I told him about my 6200 rev limiter and my 1-2 shift that starts @ 5950 rpm with the superchips....he was very convinced that I would have been floating at that rpm....what do you all think or know about valve float?
If I remember correctly the stock valve springs and cam were tested to 7200 RPM with no probs ( although no power was made there ) but it never hurts to have a better spring.... but one has to wonder just how much pressure those wimpy rockers will take... a set of adjustable rockers would be nice.... and then again, more sturdy rockers mean more weight and more spring pressure to keep things right..
If your valves are floating there would have to be some reason as to why you are losing spring pressure.. and once you hear that sound you won't forget it.. I as well have long been a fan of solid lifters, roller or otherwise... but I am not thinking there is a solid roller available for our engines.... I have heard of some of the Mustang crowd using a solid roller on a Hydraulic cam ( cheating in a certain class ) but I am not sure I would want to do that....

TJ
 

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HEMI way or no way
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Discussion Starter · #10 ·
i read it was tested at 6200 - 6400 for an extended perios of time....i beleive 6200. cant remeber where i read, it was an article somewhere
 

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MrDestinE
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I will have to research it but I think it was one of the hot rod rags... and it was not using the factory PCM.... it was one of those tests just to see.... I will have to see if I can dig it up... but it was to 7200... and the LS1 crowd does it all the time with the same kind of setup..... nothing special in the valve train at all... some of the guys are running the Comp 918s springs but only because of the extra compressablilty for the almost .600 lft cams...

TJ

TJ
 

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MrDestinE
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Im going to pull a HANKL on this one guys....

These are a few quotes I found on the internet concerning valve floating....

"Valve float is a condition which occurs when the valves on an internal combustion engine do not stay in contact with the camshaft lobe. Stiffer valve springs can help prevent this but only at the expense of increased friction losses"

"A high-rpm engine condition in which the valve lifters lose contact with the cam lobes because the valve springs are not strong enough to overcome the momentum of the various valve train components. The onset of valve float prevents higher-rpm operation. Extended periods of valve float will damage the valve train."

The first indication is loss of High RPM HP... In most cases there is no noise. BUT if continued over an extended period of time you the springs may weaken even more and the lifter is thrown further off the base of the cam causing it to slam back down onto the cam causeing a metalic noise... or even worse, piston to valve slap is also possible.... thats NOT a good thing.

SPEED SAFE, AIR RAM
 

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HEMI way or no way
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Discussion Starter · #15 ·
AIR_RAM said:
Im going to pull a HANKL on this one guys....

These are a few quotes I found on the internet concerning valve floating....

"Valve float is a condition which occurs when the valves on an internal combustion engine do not stay in contact with the camshaft lobe. Stiffer valve springs can help prevent this but only at the expense of increased friction losses"

"A high-rpm engine condition in which the valve lifters lose contact with the cam lobes because the valve springs are not strong enough to overcome the momentum of the various valve train components. The onset of valve float prevents higher-rpm operation. Extended periods of valve float will damage the valve train."

The first indication is loss of High RPM HP... In most cases there is no noise. BUT if continued over an extended period of time you the springs may weaken even more and the lifter is thrown further off the base of the cam causing it to slam back down onto the cam causeing a metalic noise... or even worse, piston to valve slap is also possible.... thats NOT a good thing.

SPEED SAFE, AIR RAM

good info...sounds awfully violent. but good impression of HankL...but what no personal observations or attacks or taking credit for someone elses publications?? ;) good try though..and thanks for the input
 

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I would have to agree with AirRam. The valve float is when your valves dont shut quick enough, leaving them open when the combustion occurs. The resulting sound is something like a Jake break. You will get a weird exhaust sound, and the "pull" of the engine will stop, because there is no confined area to have an explosion. The valves will stay open, causing the air/fuel mixture to ignite through the exhaust and intake ports. If you cannot contain the explosion, you cannot harness its power. This happened with the original engine in my firebird with the "peanut" cam, and the weak springs. No matter what you change, if the springs are strong enough to slam the valves shut, you will experience float.
 

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Nice Dog Hulk. :D
 

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Inertia ROCKS!!!!
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AIR_RAM said:
Im going to pull a HANKL on this one guys....

These are a few quotes I found on the internet concerning valve floating....

"Valve float is a condition which occurs when the valves on an internal combustion engine do not stay in contact with the camshaft lobe. Stiffer valve springs can help prevent this but only at the expense of increased friction losses"

"A high-rpm engine condition in which the valve lifters lose contact with the cam lobes because the valve springs are not strong enough to overcome the momentum of the various valve train components. The onset of valve float prevents higher-rpm operation. Extended periods of valve float will damage the valve train."

The first indication is loss of High RPM HP... In most cases there is no noise. BUT if continued over an extended period of time you the springs may weaken even more and the lifter is thrown further off the base of the cam causing it to slam back down onto the cam causeing a metalic noise... or even worse, piston to valve slap is also possible.... thats NOT a good thing.

SPEED SAFE, AIR RAM
Good explanation, far better then mine!!!
 

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Valdez Racing Team
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...man..hadn't heard HankL's name in awhile...good impersonation Nick..hehe
 
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