Has anyone who has "poly filled" their engine mount, noticed an increase in noise when driving?

I found that the left-hand mount on the spider had started to split.
So, I thought time for research and it seems a good mod, to fill the engine mount with polyurethane which would have the benefit of keeping the engine a tad more controlled.

Removed the mount, left the old rubber in there as it wasn't that bad, filled and refitted.
Quite a neat job, too.

However, now I have a sound that wasn't there before. Like air being sucked through the filter, it isn't there all the time, just low revs and under acceleration.
Do I just live with it?

If you attach an engine more rigidly (which is effectively what you've done) to whatever it's mounted on, then you're almost bound to get more transmission of vibration etc. and therefore a change in noise.

Also it's a combination of that mount, the engine side one (often overlooked cos it's impossible to see without removal (a bugger)) and the steady bar rubber that will dictate stability and transmission of vibes.

It's live with it, or you can still buy the gearbox rubber mount part (KKB10082) for about £90.

Your description of the sound doesn't sound like a vibration noise though?

Are you sure you did all those bolts up properly?

I recently did my gearbox side mount. I took a slightly different approach as it seemed to me that much of the compliance comes from the bit between the removable bit and the outer section and by removing the inner and filling that up you still leave a lot of empty space. On the Metro it is possible to remove the whole square unit and there are pictures from Metro forums where the whole thing is filled. As the square part is part of the engine frame on ours that method won't work for us. I went for filling the whole thing insitu, which meant shuttering both sides (and with the gearbox mount still attached on the right it is almost impossible to get a complete seal) I managed to fill it up about 80% full before it overflowed and that has filled up the middle (removable) part and a good proportion of the rest, certainly all the bits that take load other than when the gearbox is trying to defy gravity.

In answer to your question, no strange noises, no noticeable increase in vibrations transferred but a definite improvement in the feel when taking up drive.

What induction system have you got - If you have one of those ducted to the left hand vent ones I guess its possible you've disturbed that while doing the mount?

Thanks Sidewinder.
Reasonably sure I did the nuts and bolts up, there are only six to contend with. The engine side was done earlier in the year by the local garage using OEM parts. As you say, it's a bit of a pig to do.
Reasonably sure it is transmission noise. Only happens in gear and at the lower end of the rev counter.
Did expect more sound, just not quite as much as this, never thought it was a quiet car, up until today. Don't think I will be able to live with it. So it might be £90 + tax + delivery.

I filled mine but didn't notice any additional noise.
Would it depend on what hardness of compound you used?

I used Polytek flex 70 for filling Sven. I get the improvement in take-up Sanza, looks like you got the best of both worlds there

I wonder if I drilled a bit of it out, maybe it will soften it up a bit. There again, I might as well do it properly and get the right part. Oh Well, nothing ventured......

Powerflex do a void bush that fits the Metro engine mount. If I remember correctly it'ss listed as a Rover 200 gearbox void bush

A bit left-field but check your exhaust mounts for cracks. I had a vibration noise recently at certain revs, mostly audible on overrun, that stopped if I popped it out of gear while driving. Turned out to be a crack running along the D/S side exhaust bracket. Top just in front of the heat shield along the weld.

Not left field at all Sidewinder. On another thread I mention the exhaust (manifold) as a possible problem. I took a look today as much as I could and couldn't see anything though. It's at the local garage now, hopefully an expert will spot the problem.