[Z06] Help me understand "gear rollover" noise
01-15-2009, 11:02 PM
#1
Drifting
Thread Starter
Help me understand "gear rollover" noise
What is gear rollover, and how does it make noise?
From what I understand - this is what we call "marbles in a can".
I've also read that gear rollover can be reproduced by droping the car in a high gear relative to engine speed. In the C6 it'd be something like 6th at 20mph
Is that true?
Thanks!
From what I understand - this is what we call "marbles in a can".
I've also read that gear rollover can be reproduced by droping the car in a high gear relative to engine speed. In the C6 it'd be something like 6th at 20mph
Is that true?Thanks!
01-16-2009, 12:37 AM
#2
Le Mans Master
Why the heck would you ever want to run your car that way. 20 mph in 6th gear, equates to about 425 rpm, or far less than the engines factory unloaded idle speed. No technical explination is really needed here. It's called running the driveline way outside it's design perameters.
01-16-2009, 10:54 AM
#3
Melting Slicks
Member Since: Sep 2004
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What is gear rollover, and how does it make noise?
From what I understand - this is what we call "marbles in a can".
I've also read that gear rollover can be reproduced by droping the car in a high gear relative to engine speed. In the C6 it'd be something like 6th at 20mph Is that true?
Thanks!
From what I understand - this is what we call "marbles in a can".
I've also read that gear rollover can be reproduced by droping the car in a high gear relative to engine speed. In the C6 it'd be something like 6th at 20mph
Is that true?Thanks!
Frank Gonzalez
01-16-2009, 10:58 AM
#4
Drifting
Member Since: Dec 2006
Location: Down on the bayou La.
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U think u got marbles in a can? Put a cam in it and take a listen
There are 6 gearsets in constant mesh in the tranny, 1st, 2nd, 3rd, 5th, 6th, and the input/countershaft. There is backlash (play) in all these gears, and this is the noise u hear. Using dual-disc clutches and cams makes this much more noticable, but nothing is wrong. It's not hard to understand. And b4 u ask, the reason the clutch plays into it is because the dual-disc units do not have a sprung hub on both discs to dampen this action. Hope this helps!
There are 6 gearsets in constant mesh in the tranny, 1st, 2nd, 3rd, 5th, 6th, and the input/countershaft. There is backlash (play) in all these gears, and this is the noise u hear. Using dual-disc clutches and cams makes this much more noticable, but nothing is wrong. It's not hard to understand. And b4 u ask, the reason the clutch plays into it is because the dual-disc units do not have a sprung hub on both discs to dampen this action. Hope this helps!
01-16-2009, 05:34 PM
#5
Drifting
Thread Starter
Think of the drive shaft (between the clutch and the transmission) as a spring (which it is). If the engine is turning very low RPM, each cylinder firing is felt as a pulse that winds up the spring and makes the front face of the gears in the transmission to make contact. Then, before another cylinder fires, the spring unwinds and makes the back face of the gears come in contact. The noise comes from the clearance between the gears, which allows them to rattle as they contact the opposite face. You can hear this noise in an uninstalled transmission if you move the input shaft back and forth by hand.
Frank Gonzalez
Frank Gonzalez
Thanks
01-16-2009, 05:34 PM
#6
Drifting
Thread Starter
U think u got marbles in a can? Put a cam in it and take a listen There are 6 gearsets in constant mesh in the tranny, 1st, 2nd, 3rd, 5th, 6th, and the input/countershaft. There is backlash (play) in all these gears, and this is the noise u hear. Using dual-disc clutches and cams makes this much more noticable, but nothing is wrong. It's not hard to understand. And b4 u ask, the reason the clutch plays into it is because the dual-disc units do not have a sprung hub on both discs to dampen this action. Hope this helps!
There are 6 gearsets in constant mesh in the tranny, 1st, 2nd, 3rd, 5th, 6th, and the input/countershaft. There is backlash (play) in all these gears, and this is the noise u hear. Using dual-disc clutches and cams makes this much more noticable, but nothing is wrong. It's not hard to understand. And b4 u ask, the reason the clutch plays into it is because the dual-disc units do not have a sprung hub on both discs to dampen this action. Hope this helps!