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vibration from reverse gear level
evonigel - 5/4/13 at 08:34 PM

hi all my bec has an annoying vibration from the reverse gear lever around 60/70 mph.any ideas what may be causing it??

austin man - 5/4/13 at 08:52 PM

should you be doing 60 to 70 in reverse

are you happy that the revers is not partially engaged when in forward gears

evonigel - 5/4/13 at 09:01 PM

quote:
Originally posted by austin man
should you be doing 60 to 70 in reverse

are you happy that the revers is not partially engaged when in forward gears


could be a possibility, I only got the car yesterday so I'm looking for some pointers on where/what to look for before I start

ReMan - 5/4/13 at 09:11 PM

Poor balance/alignement on propshafts?
reverse gearbox bearings worn?
Output shaft bearing worn?
Loose prop bolts?

watsonpj - 5/4/13 at 09:35 PM

All of what reman says could be the case but as you have just got the car are you sure its not normal. Becs do have some chatter in the drive train due the differences in the gearbox design allowing more backlash. This normally is noticeable when running at constant speeds but not on overrun decel or accel.
Do you know if the prop has a torque resilent tube in it?

Pete

britishtrident - 6/4/13 at 07:59 AM

It is being excited at its natural frequency, you can change the natural frequency of the lever to move the vibration outside the speed range at which it is being excited. ie Try a heavier or lighter knob on the end.
Knobs with rubber inserts work best because they introduce some damping into the system.

adithorp - 6/4/13 at 08:38 AM

If it fades in coming up to that speed and fades out above then I'd agree with BT above.

I've got one tunnel panel that drums at 6500-7000rpm as that just seems to be the resonant frequency of that panel. It's rev' related, not speed as it does it in all gears. Just happens to be more noticable in higher gears/speeds as thats when you tend to hold at steady revs.