To Powerflex or not?.. that is the question

[TVR Beaver]

To Powerflex or not to Powerflex… That is the question?

I had it all planned out what I’d be doing on the Griff this winter and top of the list was re-working the suspension arms by blasting, re-painting and fitting Powerflex bushes all round.

However, talking to a well know ‘Racing’ company in Westcott, Bucks this afternoon on related issues (Nitron’s) they said they would not touch a car that had been fitted with Polybush units!

The reasons given were the unforgiving nature of the Polybush set up over the original rubber middled parts, such that if there was a slight alignment problem on a bracket for example, the system would wear and become loose and therefore inaccurate in quite a short period of time? They were seen as an easy fix to a problem that does not really exist as the ‘rubber’ ones are more than capable of doing the job.

So, dilemma time.. do I fit the bushes I have sat here on my desk.. or do I pull the arms, identify any failing rubber ones and replace them with like units?....

Anybody want to buy a full Powerflex bush kit.. £220 all in!!

[penno]

Well I have put powerflex in mine and the ride was transformed much smoother feels supple handles the potholes and bumps better. Had no issues with setting up even after 12 months of running around without been perfectly set-up.

I did the same two years ago shot blasted and cleaned the wishbones getting to old rubber ones out is a pain takes some time if you dont have a press. I burnt them out in the end some were very knacked though.

I have brought a set to put in my triumph vitesse this winter.

[TVR Beaver]

Looking on here I thought it was a given to fit them.. and must say the comment took me by supprise... but I havent asked around the dealers before buying them... see what their toughts are on the parts?.. may be worth a few calls tomorrow?

[spend]

Well if you do have misaligned chassis brackets I think you would be better having some visual clues that your car is a bit dangerous TBH?

[TVR Beaver]

spend said:

Well if you do have misaligned chassis brackets I think you would be better having some visual clues that your car is a bit dangerous TBH?

I don't think he was talking 1/2" out or something... may be 1mm or so.. but that would over time make the bush go oval and create a problem of the bearing having movement in it?...
They were also on about grit and water getting in (but looking at how these things go together, although they don't have lip seal's.. I'm sure once packed with grease they will be pritty sealed from that sort of stuff)... Just got the fealing they'd had a bad experiance with bearing type pivots on the arms instead of the orig rubber ones?
You can see their point here... how in-line are the two tubes on the end of the top suspention arm?.. you know how things move when you weld them etc..

Dave.. Have you fitted these?

Edited by TVR Beaver on Thursday 21st October 08:26

[markreilly]

Talk to Steve Heath

[TVR Beaver]

Will give him a call...

If for example the arm tubes are out 1mm one to the other in the same plain (which would show as a huge amount if you put 2 bars thru them to a centre point) , when mounted it would mean each side being loaded by 0.5mm misalignment....

So within the actual bearing this would be 0.25mm either end…. (if you follow what I mean)
Looking at the poly bush material they are made from… it is quite soft and I’m sure more than capable of taking up .25mm deformation over a bearing with of 50mm plus?

So I’m sure they will be fine..

It was such a strange comment and made in a way that made me wonder if any problems had been seen.. especially on our car’s where as we know… things may not be as straight as they might be !

[spend]

I've had the harder shore for over 5 years no problem.


I think there were a lot of early problems fitting them (DIY & even trade I suspect) because folks weren't spreading the brackets so that the fitted bush assembly slotted in easily and then clamping up as the suspension was torqued up. Tales abounded on here of people banging/smashing, paring bushes, knocking bolts through to align, drilling mounts, levering arms in, wrong sized bush bearings.... Similar butchery may also have been executed on chassis previously with the trend of upgrading to thrust washers BTW.

I personally use treaded bar with nuts & washers to spread the brackets. A bit fiddly to assemble on each bracket and wind them out until a spacer fits in to tell me I've expanded them enough. Even though time consuming I know there is a start & finish and no need to go round again, so when it comes to assembly everything will slot back together easily. I do it now as a 'matter of course' even if I just remove the wishbones. It's also easy enough at that time to inspect that the bolt holes are in good shape, ie if elongated they would probably need remedial action..

Correctly assembled & lubed I can see no problem with poly bushes. I was initially worried that the thrust faces might tear but I haven't seen any undue wear on mine (red superflex ones BTW). Neither have I seen any influence of heat effects, no heat shields or anything just ceramic coated manifolds. I also have adjustable wishbones which I guess if anything by the nature of the adjusters put a more skewed loading on the upper front bushes?

[TVR Beaver]

May be things have changed since the early ones?.... This is the lower rear inner and it's also used on the front somewhere
:-


The others don't have the head on the middle tube but have thrust washers either end...

Edited by TVR Beaver on Thursday 21st October 11:25

[Ant.]

TVR Beaver said:

May be things have changed since the early ones?.... This is the lower inner:-


The front ones don't have the head on the middle tube but have thrust washers either end...

I fitted one of the first sets of these years ago. No problems so far.....

[TVR Beaver]

Talked to Steve.. and I think a lot of the negatives here go back to the early days of Poly bush fitting... when the bearing was between the bolt and the bush itself....
Obviously things have moved on loads and he's had very few comlaints over the new units.... Some fitted now for a good number of years.....
Will fit and see how we get on!... cheers..

Edited by TVR Beaver on Thursday 21st October 12:21

[TVR Beaver]

Quinny said:

TVR Beaver said:

To Powerflex or not to Powerflex… That is the question?

I had it all planned out what I’d be doing on the Griff this winter and top of the list was

However, talking to a well know ‘Racing’ company in Westcott, Bucks this afternoon on related issues (Nitron’s) they said they would not touch a car that had been fitted with Polybush units!

Anybody want to buy a full Powerflex bush kit.. £220 all in!!

Just goes to show, even the so called specialists aren't immune from talking bks

As for the miss alignment argument, I've never heard such ste....

At the end of the day, these chassis were hand welded in a jig, I wouldn't be the slightest bit surprised if there was a mm difference here and there between mounting lugs etc....... But the wishbones and uprights etc are all adjustable by 10's of mm's

I personally hope I never see a rubber bush again, bd things to get in and out and get aligned without having to re-visit the vice.... So much easier with the powerflex..

My car feels lovely on the road now, it's as though the new bushes allow the suspension to do it's job, without having to overcome the forces of twisting rubber.....

Certainly won't be going back to rubber that's for certain

That will do for me then Quinny!... In they go

[shpub]

TVR Beaver said:

Talked to Steve.. and I think a lot of the negatives here go back to the early days of Poly bush fitting... when the bearing was between the bolt and the bush itself....
Obviously things have moved on loads and he's had very few comlaints over the new units.... Some fitted now for a good number of years.....
Will fit and see how we get on!... cheers..

Any difficulties that have been reported to me have been caused by problems with the wishbone/chassis dimensions being incorrect & in these isolated cases (perhaps 1 or 2), I've worked with my customers to solve their problems.

It's worth noting that Powerflex have recently announced that they are now offering a lifetime warranty on ALL their bushes. For more info see here.

[dumbfunk]

I'm amazed by that Steve as before I fitted your heat shields the front top bushes on my Griff were almost a 6000 mile service item!

To answer the original point, I'm with Quinny - junk the rubber. There was no comparison in the improvement I felt between new rubber bushes and new upgraded ones.

df

[shpub]

dumbfunk said:

I'm amazed by that Steve as before I fitted your heat shields the front top bushes on my Griff were almost a 6000 mile service item!

To answer the original point, I'm with Quinny - junk the rubber. There was no comparison in the improvement I felt between new rubber bushes and new upgraded ones.

df

My heat shields were never designed to help the bushes. It's a bit of serendipity if they have.

The Powerflex ones come with a heatshield that goes over the bush to protect it. The Superflex ones don't and seem to be more susceptible to heat degredation and a subsequent poor life. I don't have any experience of this except from customers who have changed to Powerflex units.

The problem is that there are multiple sources of poly bushes with different designs and characteristics. That does make it difficult to establish exactly what is going on when someone says my poly bushes didn't last.

[dumbfunk]

That's what I meant Steve - I ordered powerflex bushes from you but wrongly assumed the heat shielding material was your addition rather than the manufacturers. Superflex lasted 6000 miles only

[shpub]

Arrr... a question of too many heat shields.

Yep thanks for sorting that out.