Valve clatter from 5000-5500 RPM under hard accel in 3.4L?!
11-12-2009, 09:08 PM
#22
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I agree that there is not much use to rev these engines, aint no flipin rice-burnin-v-tech. But really try changin your oil with just regular old oil with full Lucas synthetic oil stabilizer. Put the whole quart of the lucas "syrup" in there and see if that makes a difference.
11-14-2009, 08:23 AM
#23
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I agree that there is not much use to rev these engines, aint no flipin rice-burnin-v-tech. But really try changin your oil with just regular old oil with full Lucas synthetic oil stabilizer. Put the whole quart of the lucas "syrup" in there and see if that makes a difference.
Still haven't had a chance to get the video I promised up. College owns your soul.
11-14-2009, 09:12 AM
#24
You shouldn't even be reving that high. The 3.4 makes all its hp before 5k rpms anyway... what you doin racing? Its a truck motor not a pocket rocket. Prolly low on oil... valves alil worn due to mileage...
12-23-2009, 05:25 AM
#26
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could be valve float 6 cyl are not made to rev at high rpms like 4cyl and small block v8s i run my 350 at around 6900 rpms and it makes noise just depends on the engine
12-23-2009, 06:39 AM
#27
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Folks--it is valve float.
Valve float has nothing to do with the type of engine or only in high rev applications. (there are advantages of certain designs but lets keep it simple--OK)
My truck with 80lb springs (~40 being stock) will pull all the way to 6k. Why because there is more pressure to counter act the force of the valve being thrown up off the cams. (Shim and Bucket it is down off the cams)
(intertia) Tendency for an object to stay in motion till adcted upon by an equal or unbalanced force.
remember the old chevy v-8s during the smog era--they would float valves at like 4k because the cams where very mild and the springs weak.
Not to mention the other factors that play into this equation......
Also, as your motor gets more miles the springs will start to relax and have less spring tension.
And--reving the motor to 6k with no load on it equals blown motor guy.
So spring rate plus cam profile equals when the valve will start to float (simplified)
Valve float has nothing to do with the type of engine or only in high rev applications. (there are advantages of certain designs but lets keep it simple--OK)
My truck with 80lb springs (~40 being stock) will pull all the way to 6k. Why because there is more pressure to counter act the force of the valve being thrown up off the cams. (Shim and Bucket it is down off the cams)
(intertia) Tendency for an object to stay in motion till adcted upon by an equal or unbalanced force.
remember the old chevy v-8s during the smog era--they would float valves at like 4k because the cams where very mild and the springs weak.
Not to mention the other factors that play into this equation......
Also, as your motor gets more miles the springs will start to relax and have less spring tension.
And--reving the motor to 6k with no load on it equals blown motor guy.
So spring rate plus cam profile equals when the valve will start to float (simplified)
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