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PostPosted: Tue Jun 13, 2017 11:03 pm 
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Hi all,
I heard a number of years ago putting a weight of some kind attached to the end of the remote housing can help balance the engine and or vibrations of the engine at the gear stick. I was told that experimenting around with this can improve and smooth things a lot.

Has anyone ever heard of a such thing and or heard this design study coming from new motor vehicles over the last two decades?


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PostPosted: Wed Jun 14, 2017 6:41 am 
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They do that in lots of new cars, in lots of different places. Go to wreckers and wander around, you might find something exactly right.................then you can tell us and save us the time and effort. Lol


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PostPosted: Wed Jun 14, 2017 12:10 pm 
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They use them on the classic range rover on the axles but for the life of me I can't remember the bloody technical name for them! Ah! I got it!! it's called a Mass damper. but what effect hanging one off a remote would be I have no idea? not much would be my guess if it's the old style remote they rattle because they wear out 30min after you rebuild them..................


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PostPosted: Wed Jun 14, 2017 12:25 pm 
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Mass Damping is used to change the natural frequency of a particular part/assembly.
If a part has the same natural frequency as another part (suspension spring, engine frequency) then the two will vibrate together.
The cheap way to change the natural frequency is to add weight. This will move the natural frequency to another harmonic.
Ever noticed how some things rattle at a particular RPM, and disappear above or below that frequency.
Now good engineering will redesign the part to ensure there are no matching frequencies. Cheap companies add mass !

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PostPosted: Wed Jun 14, 2017 7:33 pm 
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"not much would be my guess if it's the old style remote they rattle because they wear out 30min after you rebuild them..............."

That's probably because you're not actually fixing the problem....

Haven't had to rebuild mine yet... its only 54 years old...and it doesn't rattle. I followed some good advice I was given years ago. A Morris Minor front suspension bush shoved over the small end of the gear lever will damp out all the sizzle.

If you happen to have a quick-shift the bush will be too short but a suitable length of heater hose is an excellent - if slightly less durable (you'l probably have to install a new bit every 10 years or so 8) solution.

Cheers, Ian


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PostPosted: Thu Jun 15, 2017 6:49 pm 
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Phil 850 wrote:
Mass Damping is used to change the natural frequency of a particular part/assembly.
If a part has the same natural frequency as another part (suspension spring, engine frequency) then the two will vibrate together.
The cheap way to change the natural frequency is to add weight. This will move the natural frequency to another harmonic.
Ever noticed how some things rattle at a particular RPM, and disappear above or below that frequency.
Now good engineering will redesign the part to ensure there are no matching frequencies. Cheap companies add mass !



Rolls Royce & Jaguar use mass dampers in various places.

Brad

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PostPosted: Fri Jun 16, 2017 2:43 am 
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MiniBrad wrote:
Phil 850 wrote:
Mass Damping is used to change the natural frequency of a particular part/assembly.
If a part has the same natural frequency as another part (suspension spring, engine frequency) then the two will vibrate together.
The cheap way to change the natural frequency is to add weight. This will move the natural frequency to another harmonic.
Ever noticed how some things rattle at a particular RPM, and disappear above or below that frequency.
Now good engineering will redesign the part to ensure there are no matching frequencies. Cheap companies add mass !



Rolls Royce & Jaguar use mass dampers in various places.

Brad

I'd forgotten about the ones on the Rolls-Royces, they were fitted to the Diff. carrier at the mount points I was told at the factory they were used to cure a whine from the Diff. at cruise speed.


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PostPosted: Fri Jun 16, 2017 12:22 pm 
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minimans wrote:
MiniBrad wrote:
Phil 850 wrote:
Mass Damping is used to change the natural frequency of a particular part/assembly.
If a part has the same natural frequency as another part (suspension spring, engine frequency) then the two will vibrate together.
The cheap way to change the natural frequency is to add weight. This will move the natural frequency to another harmonic.
Ever noticed how some things rattle at a particular RPM, and disappear above or below that frequency.
Now good engineering will redesign the part to ensure there are no matching frequencies. Cheap companies add mass !



Rolls Royce & Jaguar use mass dampers in various places.

Brad

I'd forgotten about the ones on the Rolls-Royces, they were fitted to the Diff. carrier at the mount points I was told at the factory they were used to cure a whine from the Diff. at cruise speed.


Exactly my point.
Instead of re-engineering the diff to eliminate the whine, they added weight. They took the cheap way out.
The cost of the engineering, testing, and then retrofitting all of the cars was too expensive compared to doing it right :cry:

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PostPosted: Sat Jun 17, 2017 9:04 am 
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I find if the remote shift rattles it's because the top nylon ring has worn and is sitting on the housing. There is then no preload on the ball.
New ones are cheap but I have made them when scarce.

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