Another DIY engine mount guide

[rb_rx_gtr]

Hello all

I recently bought an RX8 which had collapsed engine mounts and after checking the cost of new ones thought I would follow various guides and videos on filling them with Polyurethane.

Most of the guides start with cutting the rubber seal away at the bottom of the bush and draining the oil. This is pretty straight forward. Use IPA and acetone to clean up to ensure the rubber is grease/oil free allowing for a good bond.

Looking at the guides, they drill holes in the plastic rings to allow the air to escape from the mixture. Instead I used a 54mm hole saw then removed the rings completely with pliers. This allows easier pouring of the polyurethane and less risk of large pockets of trapped air.

I have mounted them to the car and there is significant reduction in vibration as the old bushes had collapsed onto the brackets and far less engine rocking during gear change.

The Polyurethane I used was a 1L kit, however I had so much left, that a 500ml kit would of been fine.

Polytek Poly PT Flex 70 Liquid Casting Rubber

[rb_rx_gtr]

So after 9 months the mounts are still strong, no cracks. Only thing I would change is maybe using pt flex 80, especially for track.

[PaulAV]

Used the same method myself, with the hole saw, makes sense as there is no chance of air bubbles getting trapped

[untakenname]

I used the traditional drill method, using a hole saw does seem to be quicker and easier to get all the plastic swarf out.
One thing to check depending on the makers of the polyurethane is if it cures at room temperature of if it's meant to be cured at a higher temperature, tbh after a few drives the heat (especially on the right) will have heat cured it anyways.

[rb_rx_gtr]

The curing process creates heat, but I did leave them a couple of days before fitting at room temperature.

[njkmr]

Used the same method and mine are still going strong after 6 months or so.