Engine sound dampening

[Timmy Wainwright]

Hi all,

when cruising in my MGB with the hood down, I am in heaven ! When the hood is up, the sound from the engine isn't really bad but attempting to dampen the noise wouldn't go a miss. Has anyone done this before and can offer any ''sound advice'' see what I did there?! lol

Am going to be replacing the carpets over the winter so will hopefully add something under that to stop some noise getting through :-)

Many thanks in advance,

Tim

[Jim Haines]

The same noise increase happens on my 'B', but I suggest the root problem is actually the design/construction of the body which is doing this.
If you look at the rear half of the body the axle is actually inside what amounts to almost a box which simply amplifies the noise of the axle together with the tyre/road noise, sending it all up into the cabin. With the roof up you have simply blocked the 'escape' path.
Looking back at historical claims made against MG this was actually a big problem, particularly from America, before it was realised what was happening. The number of warranty claims for axle rebuilds was alarming, until they came to the conclusion that there was really nothing that could be done...
This is pretty well documented on some of the American sites discussing axle noise. It seems some forms of sound deadening could be stuck on the body panels, but how successful this was I really don't know.
I have only just had my axle completely rebuilt and whilst the bearing noise I had has gone the road noise remains....
Good luck - would be interested to hear if you find any way to improve things.

[George Wilder]

Tim
The MGB was designed long before the the world of NVH (Noise Vibration and Harshness) was scientifically introduced to car design.

One of the major contributors to engine noise is the after market air cleaner by K&N and others. May give a BHP or two but will certainly increase the noise. If you have those, try fitting the originals, much less induction noise, a quieter car and you will not really notice the performance difference.

There is little one can do except try fitting some soundproof material over the gear box tunnel and under the carpets at the end of the footwells though I fear it will make little difference. Modern engine installations have better mountings for NVH, quieter fans, quieter intakes, better body insulation etc.

My car has its works hardtop on now - to think the car won the GT Class in the 64 Monte in this configuration - I am glad my hearing is not perfect!

I guess the noise is all part of driving around in a car designed over 50 years ago - things have moved on as they say.

[Rick Benson]

Hi Tim,
I have often thought the same as you, it would be nice to be able to talk to the passenger! A thing I read on this a while ago said that all holes through the bulkhead should be sorted out with grommets etc. the point being holes make a big difference. This was highlighted to me on my comfy and quiet Volvo V70 when after some work changing clutch pedal switch it was much noisier. I could hear tappet noise and the like and after some investigation I found the problem was the gaiter round the steering column as it goes through bulkhead. The thoughtful Swedes provide a needle roller bearing to go between the gaiter and the shaft and this bearing had popped out. There was a tiny gap but the noise increase had been significant which was cured after 15minutes on my back in the foot well and some swearing to "pop" it back in.

I'm not sure how much this sort of thing contributes to our noises but maybe something to bear in mind.

Rick