Thoughts on poly bushes - particularly the big diff one

[schimg]

Hi folks,

I am part way through a body off chassis reclamation exercise (chimaera) and have been supplied (by a known TVR establishment, who fit these as replacements) with a large poly bush for the diff, this is a Powerflex one, and has been fitted.

I have replaced all of the bushes in the wishbones front and back with standard one's, however I need to replace the 3 outer ones situated in the rear hub assemblies. Was thinking of fitting poly bushes in these to partially firm up the rear end.

I have some questions on this topic:

1. Following a conversation with a respected supplier I have been advised to ditch the main diff "powerflex" one as:
"It will not last five minutes, think of how it has been constructed and what it has replaced, then think of the amount of torque going through it, take it out bin it and replace it with the standard one" (I do not want to have this problem as removal and fitting of this item is a sod with the body on, I understand that this is the first job that they do at the factory after the chassis has been fabricated!
It is also difficult to get sufficient torque on this when refitting.

2. I have also been advised against fitting poly bushes in the outer rear hubs too.....as these would be too soft? what are peoples thoughts here/part numbers?

3. If I go for the standard parts as replacements does anyone know if these are fitted to other cars and have been lifted from the partss bin once more?

I hope this makes sense! Oh I do not intend to track the car, thanks in anticpation.

Steve.G.

Ah well back into the nice warm (not) garage then for some

>> Edited by schimg on Saturday 26th November 09:40

>> Edited by schimg on Saturday 26th November 09:42

[Guillotine]

steve,

I wouldn't use polys on the powertrain either.

besides strength issues, i'm sure the transmited noise and vibration would be horrible!

and I use alot of polys...and Track, alot!

andy

[trackcar]

All I can say is I've been fitting poly bushes as upgrade items and longer lasting std service replacements for 4 years and not had one poly diff bush fail. .. you can't say that of the std tvr rubber bush.!!

and what's that rubish about the outer hub bushes?

fact : the std rubber bushes fail on the chim/griff with alarming regularity. why would anyone want to fit a std replacement when there's an upgraded alternative available?

is there maybe some places who want to protect their future workload / parts sales by constantly supplying rubber bushes that fail?

[mrmaggit]

I echo Joolz. He fitted the poly bushes to Wol as a fit-and-forget item. Why anybody would replace a failed (or going to) item with one the same is beyond me.

Just my 2p

[GreenV8S]

Poly bushes come in different gades, and maybe your 'respected supplier' has had a bad experience with the wrong grade?

[antonyj]

Just before I fitted the new powerflex suspension bushes, I too spoke to a main dealer about other types of polybushes, who said the polybushes dont work on the TVR's, as the original design is a shear design of bush.
"no good at all" he said.
However he DOES stock them !!!!!!

[schimg]

Guillotine said:

steve, I wouldn't use polys on the powertrain either. besides strength issues, i'm sure the transmited noise and vibration would be horrible! and I use alot of polys...and Track, alot! andy

Andy,

Thanks for this, I guess the increase in noise level would be a disadvantage.

At the risk of sounding a bit blonde here, but has anyone actually fitted the powerflex main diff bush?

AND if so has there been any noticeable increase in noise level,I have a roll cage in mine too so this might make a differnce?

AND how has it performed?

Steve.

[schimg]

trackcar said:

All I can say is I've been fitting poly bushes as upgrade items and longer lasting std service replacements for 4 years and not had one poly diff bush fail. .. you can't say that of the std tvr rubber bush.!! and what's that rubish about the outer hub bushes? fact : the std rubber bushes fail on the chim/griff with alarming regularity. why would anyone want to fit a std replacement when there's an upgraded alternative available? is there maybe some places who want to protect their future workload / parts sales by constantly supplying rubber bushes that fail?

Thanks for this, so I guess you are saying that replacing the three outer bushes on my rear hub with poly one's would be a goer then and there would be no problems running a mixture?

Is there any particular grade/type you would recommend? As I say all of the other bushes have been replaced with standard items, so I don't want to change them just yet.

Steve

[schimg]

antonyj said:

Just before I fitted the new powerflex suspension bushes, I too spoke to a main dealer about other types of polybushes, who said the polybushes dont work on the TVR's, as the original design is a shear design of bush. "no good at all" he said. However he DOES stock them !!!!!!

Yep I know exactly what you mean, same with a lot of things in the TVR community, some (not all) individuals change their opinions/advice with the weather it would appear.

Still all good clean fun

So how has the car behaved since you changed to poly bushes then, is it a firmer drive, or perhaps more "twitchy"?

Thanks,

Steve

[bugsy]

As far as Powerflex are concerned, their diff bushes work extremely well and I have supplied them with no notified problems since the end of July from Chims up to Tuscans.

For those considering using polybushes on wishbones etc, we now have 15 cars running on the new bushes and despite some initial teething problems specific to TVR's, namely heat from the manifolds and welds cutting up shoulders on the bushes, Powerflex are comfortable with the current specification and whilst not complacent, feel that they work to a high standard.

[schimg]

bugsy said:

As far as Powerflex are concerned, their diff bushes work extremely well and I have supplied them with no notified problems since the end of July from Chims up to Tuscans. For those considering using polybushes on wishbones etc, we now have 15 cars running on the new bushes and despite some initial teething problems specific to TVR's, namely heat from the manifolds and welds cutting up shoulders on the bushes, Powerflex are comfortable with the current specification and whilst not complacent, feel that they work to a high standard.

Derek,

Thanks for this

I hope that the shocks got back to you, thanks for the "Loan" I put the original one's back on in the end

regards,

Steve.

[trackcar]

schimg said:

trackcar said: All I can say is I've been fitting poly bushes as upgrade items and longer lasting std service replacements for 4 years and not had one poly diff bush fail. .. you can't say that of the std tvr rubber bush.!! and what's that rubish about the outer hub bushes? fact : the std rubber bushes fail on the chim/griff with alarming regularity. why would anyone want to fit a std replacement when there's an upgraded alternative available? is there maybe some places who want to protect their future workload / parts sales by constantly supplying rubber bushes that fail? Thanks for this, so I guess you are saying that replacing the three outer bushes on my rear hub with poly one's would be a goer then and there would be no problems running a mixture? Is there any particular grade/type you would recommend? As I say all of the other bushes have been replaced with standard items, so I don't want to change them just yet. Steve

there's no problems replacing just one bush or a set of bushes in one area on the car.

There is no extra harsness from switching to poly for the suspension either, there's a whole load of useless info circulating .. have you *felt* the stiffness of the std TVR rubber bush? there's *no* movement, it's got so little rubber in it that it's virtually solid anyway! The powerflex are a low-friction rotating design as opposed to the bonded rubber bushes TVR fit as std .. if anything they will make the ride *more supple* as you don't have the stiffness of having to rotate a bonded rubber section ..

[bugsy]

schimg said:

Derek, Thanks for this I hope that the shocks got back to you, thanks for the "Loan" I put the original one's back on in the end regards, Steve.

Steve
I do feel sorry for the situation you found yourself in and nose, cutting off springs to mind when I think back on my reaction to the happenings.

However they were the old Spec dampers, pre-Gugi being employed to fine tune the bump/rebound plus other changes and when you are ready to change the dampers, there will be a new kit available in the new year and you can have one at cost, as well as any bushes you may require.

Bugsy

[gooner]

Bugsy

what's the new kit available in the New Year? I'm just about to order a the damper/springs kit off you - should I wait?

gooner

[MrsFlipFlopGriff]

Steve,
We are supposed to be having the rear bushes, including diff, done this week but I can't seem to get in contact with Mr Venn. Left a message both Thu and Fri - maybe he's misplaced his phone again - it's not somewhere round yours is it?
If you do see him get him to call me.
I'll let you know how it goes.
FFG

[SteveGRF]

Since this controverse subject has aired again -

Has any body fitted the new material PolyFlex bushes to rear Griff wishbones yet ?,
how are they functioning ?

SteveGRF.

[schimg]

MrsFlipFlopGriff said:

Steve, We are supposed to be having the rear bushes, including diff, done this week but I can't seem to get in contact with Mr Venn. Left a message both Thu and Fri - maybe he's misplaced his phone again - it's not somewhere round yours is it? If you do see him get him to call me. I'll let you know how it goes. FFG

Andrea,

Yes he did say a couple of weeks ago that yours P and J was booked in for some bushes, I was over at his place on Friday, he is very busy (as ever) if I speak with him I will ask him to contact you no problem.

The way the work is progresing with the rebuild I will need to make my choice in the next few days over poly bushes. Getting the front hub assemblies shot blasted tommorrow, then will be rebuilt with new top and bottom ball joints/track rod ends and bearing seals/covers, got all the parts so shouldn't take much time, I still need some decent shocks at the right money though.

Feel free to pop over and have a look at the bling chassis!

Steve.

[schimg]

trackcar said:

schimg said: trackcar said: All I can say is I've been fitting poly bushes as upgrade items and longer lasting std service replacements for 4 years and not had one poly diff bush fail. .. you can't say that of the std tvr rubber bush.!! and what's that rubish about the outer hub bushes? fact : the std rubber bushes fail on the chim/griff with alarming regularity. why would anyone want to fit a std replacement when there's an upgraded alternative available? is there maybe some places who want to protect their future workload / parts sales by constantly supplying rubber bushes that fail? Thanks for this, so I guess you are saying that replacing the three outer bushes on my rear hub with poly one's would be a goer then and there would be no problems running a mixture? Is there any particular grade/type you would recommend? As I say all of the other bushes have been replaced with standard items, so I don't want to change them just yet. Steve there's no problems replacing just one bush or a set of bushes in one area on the car. There is no extra harsness from switching to poly for the suspension either, there's a whole load of useless info circulating .. have you *felt* the stiffness of the std TVR rubber bush? there's *no* movement, it's got so little rubber in it that it's virtually solid anyway! The powerflex are a low-friction rotating design as opposed to the bonded rubber bushes TVR fit as std .. if anything they will make the ride *more supple* as you don't have the stiffness of having to rotate a bonded rubber section ..

Thanks, this is the sort of thing I want to hear, which ones should I go for then?
Is there any supplier you recommend?

Cheers,

Steve.

[schimg]

bugsy said:

schimg said: Derek, Thanks for this I hope that the shocks got back to you, thanks for the "Loan" I put the original one's back on in the end regards, Steve. Steve I do feel sorry for the situation you found yourself in and nose, cutting off springs to mind when I think back on my reaction to the happenings. However they were the old Spec dampers, pre-Gugi being employed to fine tune the bump/rebound plus other changes and when you are ready to change the dampers, there will be a new kit available in the new year and you can have one at cost, as well as any bushes you may require. Bugsy

Derek,

Yes, it was less than ideal to say the least, I had my expectations raised certainly, that said I guess this is not the appropriate medium for a rant and I won't lower myself.

All I can say here is that I acted in good faith and walked away from it oweing no one any favours.

I hope that the my feedback was of some use to you, I thought that the shocks were good, the car was loads more stable at speed, and the ride damm good, plus it looked the DB's lowered. this made me realise what I had been driving around, it drove like it was on the North Sea when I refitted my originals, one of which is blown!

It would be a shame to refit these after all the work I am doing to the chassis, I will speak with you.

Thanks for the offer

Steve

[schimg]

SteveGRF said:

Since this controverse subject has aired again - Has any body fitted the new material PolyFlex bushes to rear Griff wishbones yet ?, how are they functioning ? SteveGRF.

Steve,

Whats all this about then? "new material" can someone throw some light on it for us?

Steve. G.