DIY Poly bushes

[Bbrooks]

Hi, I'm new here and to Renaults but decided to get myself a Ph2 172 as a cheap track car. I'm slowly working my way round the car sorting everything to get it ready for its firt outing.
I've read a lot on here about the benefits of using uprated engine / gearbox mounts and decided that seeing as mine were shot I'd go with some upgraded items. After seeing the how much they were I decided I could probably achieve the same outcome for less outlay, so here is my attempt on poly busing my own gearbox mount...

First of all I had to make a template / container to be able to pour the polyurethane rubber into. I did this by cutting up a plastic cup and then sealing it using RTV silicone.

Once that was dry and I was sure it was water tight (it wasn't first time round) I then mixed up the polyurethane rubber which come in two parts and needs to be mixed 50 / 50 by weight.

It's then poured in to the mould (It only has a 5 minute working time so no time to waste!) and left for 2 hours before it can be removed.
When I removed it it looked a little bit sloppy (Did I mention you've got to be quick when pouring it).

But once trimmed I think it came out OK for a first attempt.

All I have to do now is wait 7 days for it to cure fully and then it's straight on to the car, hopefully with some improvement.

Sorry for the long first post but thought at least 1 person may be interested.

Thanks,

Ben

 

[Paul.M]

Good effort on the diy, this isn't something I can remember being done on here before.

Let us know how you get on

 

[bozothenutter]

Interesting!
Where did you get the materials?
Do they come in different hardnesses?

 

[Bbrooks]

I got the materials from a Fibreglass supplies company, the product some in 5 different hardness ratings Shore 85A / 70A / 60A / 50A / 20A.

I've made my one from 85A - which is between the Powerflex purple (80A) and black (95A) bushes so should be a good test.
Ideally I need to put the bush in to a degassing chamber to remove all of the bubbles before it cures but I wanted to prove the concept before splashing out on any equipment.

 

[bozothenutter]

I once built a degassing chamber from a tupperware box and a vacuumcleaner , was casting resin at the time though

 

[Bbrooks]

Finished pouring the engine mount and now just waiting for it to cure, I think it turned out better than the gearbox mount.

Hopefully they'll make a big improvment once finally on the car!

 

[Bbrooks]

Finally got both the mounts installed.


It has eliminated all movement of the engine under no load and seems to have helped with the response of the car.
There is now much more whine being transmitted through to the cabin from the gearbox and also A LOT of vibrations. I've only done 10 miles since fitting so hopefully they'll settle down once i've got some more miles on them.

 

[mossyv6]

Great post and will be useful for beefing up exhaust mounts

 

[Gus]

@Bbrooks , That looks really interesting and was wondering if you could use the same technique for making polybushed exhaust mounts .
Any chance you could link to where you bought the kit.

 

[TimR26]

Sounds like it's worked similar to the Vibratechnic mounts but at a fraction of the cost.

 

[-Jamie-]

Nice work, Ive literally just done the same this week with some mount for my Megane, Using what looks like the same stuff that you used.

I may of went a bit hard though, I get some epic vibrations and noises along with transmission whine now LOL

 

[dablk]

If you could knock out working exhaust mounts I bet 95% of the forum would be interested.

From what I gather those that have fitted the polybush insert have found its too rigid and snaps the exhaust hangers. So basically just beefing up a standard one. Excuse my ignorance but could you pour it around the rubbers one a standard one?

 

[Bbrooks]

@Bbrooks , That looks really interesting and was wondering if you could use the same technique for making polybushed exhaust mounts .
Any chance you could link to where you bought the kit.

Making exhaust mounts is next on my list so i'll post up progress on htis once I start. This is the kit I used http://www.mbfg.co.uk/polyurethane-rubbers/pt-flex-85-rubber.html

Nice work, Ive literally just done the same this week with some mount for my Megane, Using what looks like the same stuff that you used.

I may of went a bit hard though, I get some epic vibrations and noises along with transmission whine now LOL

It's definitely way too hard for a daily! If it was a daily i'd use a much softer rubber, that way I'd get to keep my fillings LOL.

If you could knock out working exhaust mounts I bet 95% of the forum would be interested.

From what I gather those that have fitted the polybush insert have found its too rigid and snaps the exhaust hangers. So basically just beefing up a standard one. Excuse my ignorance but could you pour it around the rubbers one a standard one?

Yep, should be able to just pour a reinfocment layer around the existing mount to help beef them up a bit.

 

[-Jamie-]

Yeah the exact stuff I've used, I kinda wish i had went for a softer one but hey Ho, its done now lol