BTR diff bushes and oil ?
Discussion
this covers GKN or BTR bobfather said:
The Ginetta G33, very similar setup, has a removable cover plate built into the parcel shelf for access to the top diff mount from inside the car. I've been wondering whether that would be a worthwhile route to access the TVR top mount
Phazed did this on his 4.6 car IIRC to access the top mounting bolts, in all fairness once that top mount bush is done its done even the standard rubber one get a bit of a slating but these last years in moderate/road use etc Edited by Zener on Tuesday 9th March 11:54
Pinx said:
Thanks for all the replies, I'm just trying to work out whether to buy standard bushes or go with Poly ones, I've heard some people say that Poly ones make the car handle like cr*p..
Pinx
Whoever told you poly bushes ruin the handling haven't a clue Pinx
and I would highly recommend you change the rear top diff mount for poly like I mentioned previously , your car your choice 
I assume rubber was used as they tended to be connected to tin box cars so vibration could be an issue.
The top bush looks like it is clamped so tight it barely moves at all on a Tvr so with its rather solid chassis unlikely to cause issues if you use a poly bush type.
It will get very hot on top the Dif so will they last as long as rubber is a good question but they are easier to replace in situ so I’d go for it.
I have no experience of said bushes but I’m sure some cars have had them fitted 10 years or more and I can’t remember someone ever complaining about them which is always a good sign.
The top bush looks like it is clamped so tight it barely moves at all on a Tvr so with its rather solid chassis unlikely to cause issues if you use a poly bush type.
It will get very hot on top the Dif so will they last as long as rubber is a good question but they are easier to replace in situ so I’d go for it.
I have no experience of said bushes but I’m sure some cars have had them fitted 10 years or more and I can’t remember someone ever complaining about them which is always a good sign.
sapper said:
For your diff and ARB I’d use poly everywhere else stick to the original type. I’ve done poly as a full set and it never felt right, so this TVR I didn’t use them and went for OEM and feels much better. But for the diff and ARB I used polly. Just to give the diff a bit more play.
Interesting... does anyone really advocate giving the diff 'a bit more play'? By the same token, why give ARBs 'more play'? In race applications they run in roller bearings and the links are rose jointed!
Compliant bushings are designed to reduce NVH whilst strictly controlling movement, and modern materials can be synthesised to do that (and fulfil other criteria too) rather better than plain old organic rubber, surely. There are applications where controlled deflection is called for (eg 'void' bushes to alter toe under braking) but, in my experience, 'play' is not a requirement in the mounting of diffs or ARBs.
However, I think the main reason for fitting a two-part poly bush at the rear of the diff is the ease of replacement. Having said that, I managed to extract my one-part poly bush, and it remains reusable.
TwinKam said:
Interesting... does anyone really advocate giving the diff 'a bit more play'?
By the same token, why give ARBs 'more play'? In race applications they run in roller bearings and the links are rose jointed!
Compliant bushings are designed to reduce NVH whilst strictly controlling movement, and modern materials can be synthesised to do that (and fulfil other criteria too) rather better than plain old organic rubber, surely. There are applications where controlled deflection is called for (eg 'void' bushes to alter toe under braking) but, in my experience, 'play' is not a requirement in the mounting of diffs or ARBs.
However, I think the main reason for fitting a two-part poly bush at the rear of the diff is the ease of replacement. Having said that, I managed to extract my one-part poly bush, and it remains reusable.
I’ve got rose jointed links on the ARB, the poly are almost an exact replacement for the TVR set up where the ARB is attached to the chassis uprights.By the same token, why give ARBs 'more play'? In race applications they run in roller bearings and the links are rose jointed!
Compliant bushings are designed to reduce NVH whilst strictly controlling movement, and modern materials can be synthesised to do that (and fulfil other criteria too) rather better than plain old organic rubber, surely. There are applications where controlled deflection is called for (eg 'void' bushes to alter toe under braking) but, in my experience, 'play' is not a requirement in the mounting of diffs or ARBs.
However, I think the main reason for fitting a two-part poly bush at the rear of the diff is the ease of replacement. Having said that, I managed to extract my one-part poly bush, and it remains reusable.
As for the diff, it works for me with poly as I think it softens the impact between the diff and the mounting bracket much more than the original bushes.
TwinKam said:
However, I think the main reason for fitting a two-part poly bush at the rear of the diff is the ease of replacement.
I think you meant to say "ease of fitting"There is nothing easy about removing the old rubber bush
Looks like I fitted the upper rear bush in 2013 and when I checked earlier today it was fine
Does anyone know the size of the pinion shaft oil seal?
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