Propshaft ringing

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Re: Propshaft ringing

Postby tforturton » 24 Nov 2017, 11:09

How many of you are using non-standard wheels and tyres....?
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Re: Propshaft ringing

Postby syncropatrick » 24 Nov 2017, 12:08

Another recommendation-
These people in Bristol know their stuff as well.
http://www.prop-shaft.com
At least one forum member has a shaft made by them, and another a rebuilt one.
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Re: Propshaft ringing

Postby footstuck » 03 Jan 2018, 08:50

It has never been an issue with me because I run in the decoupled state until road conditions dictate otherwise Using the decoupler completely stops the Ringing
This doesn’t mean to say that the cause is emanating from the gearbox though.
I wonder if the use of a solid shaft replacing the viscose coupling
Stops the fire bells?
Is anyone using a solid shaft in their transmission?
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Re: Propshaft ringing

Postby silverbullet » 03 Jan 2018, 19:17

footstuck wrote:It has never been an issue with me because I run in the decoupled state until road conditions dictate otherwise Using the decoupler completely stops the Ringing
This doesn’t mean to say that the cause is emanating from the gearbox though.
I wonder if the use of a solid shaft replacing the viscose coupling
Stops the fire bells?
Is anyone using a solid shaft in their transmission?
You know thats dangerous talk..

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Re: Propshaft ringing

Postby hugomonkey » 04 Jan 2018, 14:06

Get used to the noise and forget about it!
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Re: Propshaft ringing

Postby rollercoaster » 16 Jan 2018, 12:40

Yes I am getting used to it,
but I know it doesnt have to be there,
and dont want it either.
Easier than curing tinitus probably!
So lets work out how to do it..
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Re: Propshaft ringing

Postby Aidan » 17 Jan 2018, 07:38

rollercoaster wrote:So lets work out how to do it..


Take the prop off and see how much backlash there is on the input side of the front diff and compare with the backlash at the output side of the gearbox, the ring is often caused by the take up of the combined backlash amplified by any play in components, if there is fair wear in the transmission or the set up of these wasn't done correctly when previously repaired then it will be apparent. On the front diff the take up of load into the 10kg mass of the VC is what makes the clonk that causes the prop to ring; worn splines on the input shaft or VC case will exascerbate the effect. On a tight rebuilt transmission with good VC and input shaft there is only a couple of degrees of backlash felt at the flange. So if there's 5 plus degrees of backlash at the front diff then you'd be thinking worn VC /input shaft splines or worn pinion bearing, drop the oil see if the drainplug magnet shows wear.
Whilst the prop is off you can also have a feel of how much force required to turn the VC, 13mm spanner on a bolt through the flange and you should be able to slowly rotate without the spanner cutting into your hand because you are using so much force - it's not definitive but useful indication same as jacking up one front wheel with prop on and trying to rotate that one wheel, you should be able to very slowly rotate it without too much force, you can put a 24mm socket on the nut and a torque wrench and measure the force, likely to be 80-100Nm on a ok VC
Again it's only a guide

Also as noted worn bushes inside the donut end of the prop can also cause a small internal clonk that will make the prop ring on take up
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Re: Propshaft ringing

Postby rollercoaster » 17 Jan 2018, 12:43

Brilliant!
Thanks for the very considered expert thoughts on this, just what we need.
I will take off the prop and do what you say.
The VC is newly refurbed by Holman Engineering but dont think he does anything with the splines.
The other worn parts you mention.. some or all of them could be attended to by your good self?
Its due some time off the road soon for an engine change,
so a good time to ask you to look at the other bits, if you are not too far booked in advance?
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Re: Propshaft ringing

Postby Aidan » 17 Jan 2018, 19:40

Ian would only refurbish good cores and would replace any badly worn parts so it's unlikely to be a spline wear issue if the VC originally came from that diff as the input shaft would be matching in wear, so sounds more like wear in the prop bushes or UJs.
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Re: Propshaft ringing

Postby rollercoaster » 17 Jan 2018, 22:48

Good news.
Wont be able to take the prop off for a few days,
but will come back with the results.
Thanks
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Re: Propshaft ringing

Postby silverbullet » 18 Jan 2018, 09:54

FWIW and from what I have seen, the T3 syncro propshaft has an unusually small diameter for its length, as one-piece props go.
It can't help the tendency to resonate (whatever the cause) but I still think that the choice of materials in its constructipn is key i.e. use of an internally damped tube or a twin-wall tube with rubber isolator.

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Re: Propshaft ringing

Postby footstuck » 25 Jan 2018, 23:26

I would have tried foam filling mine if the problem hadn't disappeared.
The expanding foam route would cost very little but would need thinking about.
The ringing on mine stopped when i fitted the anti-ringing device :wink:
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