V8 Saloon - too loud

KV8
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Location: Cambridgeshire

Re: V8 Saloon - too loud

Post by KV8 » Fri Aug 10, 2018 9:53 pm

Hello Ivor

Many Thanks Some good ideas there about tracing sound leakage via the bulkhead. There is no sound insulation on the engine side of the bulkhead other than the (heat?) insulation around the heater box. Should there be?

Despite being sold in the 60's as a sports saloon I cannot believe that as it was sold alongside the MK2 Jag as a "Luxury Version" when it appears noisier than even a 3.8 Jag.

Whilst not exactly quiet my memories of my late fifties Wolseley 6/90 are of a quieter car.

Thanks

H

Dobbinridesagain
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Location: Gloucester

Re: V8 Saloon - too loud

Post by Dobbinridesagain » Tue Aug 14, 2018 8:46 pm

No you're not missing any sound insulation***. Don't offhand recall seeing any car of any make from the 60s with sound lagging on the bulkhead.
I have seen cars with aftermarket bonnet blankets, and our Silver Shadow had one ex-works, but not convinced it does much for the cabin.
The Shadow also had a double-skinned bulkhead, no lagging. Was a right pain if one wanted to poke any wiring through it.

Old, hardened, engine and gearbox mountings may also make a noise contribution.

Daimler/Jaguar no doubt had a whole department working on noise, vibration, harshness. Now, you just have you.

Ivor

*** Wrong. See post below.
Last edited by Dobbinridesagain on Fri Aug 17, 2018 8:58 am, edited 1 time in total.

KV8
Posts: 181
Joined: Sun Mar 06, 2016 7:05 pm
Location: Cambridgeshire

Re: V8 Saloon - too loud

Post by KV8 » Tue Aug 14, 2018 9:07 pm

Dobbinridesagain wrote:
Tue Aug 14, 2018 8:46 pm
No you're not missing any sound insulation. Don't offhand recall seeing any car of any make from the 60s with sound lagging on the bulkhead.
I have seen cars with aftermarket bonnet blankets, and our Silver Shadow had one ex-works, but not convinced it does much for the cabin.
The Shadow also had a double-skinned bulkhead, no lagging. Was a right pain if one wanted to poke any wiring through it.
Old, hardened, engine and gearbox mountings may also make a noise contribution.
Daimler/Jaguar no doubt had a whole department working on noise, vibration, harshness. Now, you just have you.
Ivor
Many thanks again. The engine and gearbox mountings were replaced when the the engine & gearbox were re-installed after the engine rebuild in 2015.

I was discussing this with one of my sons who over the years has owned numerous motor bikes of all types. He said it is well known in the biking fraternity that if you want to make your bike a lot louder then fit a stainless exhaust. I have ordered some exhaust lagging and will report back after I have fitted it.
H

Petelang
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Re: V8 Saloon - too loud

Post by Petelang » Wed Aug 15, 2018 3:10 pm

I think you should find the sound insulation is on the cabin side of the bulkhead. It's also behind the instrument panel and stuck under the pedal box. It's a "hardura" type of sheet with fibre layers on top, a bit like floor insulation material. If someone has been messing about under there with wiring it may have been removed as it gets in the way and is a swine to put back.
I would think, and surprised no one else has suggested so far, that you need to take some noise readings with a decibel reading device, you can usually get some kind of adaptation to fit a multimeter, so that you have clear figures for analysis and indeed comparison then with another car. Noise can be such a subjective thing and if you're a bit mutton Jeff, like me, it's not quite such a problem any more.
I recall having to do tests with interior noise on bus bodies with an exercise to reduce noise from engine and transmission by adding underfloor sound deadening materials and we employed noise meters to test and compare.
Peter
Peter Langridge
Cloud Nine Classic Weddings, Nottingham.

Sydsmith
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Location: Aberystwyth Wales

Re: V8 Saloon - too loud

Post by Sydsmith » Wed Aug 15, 2018 4:25 pm

A cheap sound level meter is available on ebay for under £15, may not be very accurate but it will be fine for comparisons.

Another thought KV8. My V8 250 has sound deadening material which looks original glued to the underside of the bonnet, I guess if that was not there it would make a big difference, has yours been removed or perhaps not got one.

Just as a matter of point, my boss in the 60's first had a V8 big bumper, then a Jaguar 2.8 and soon went back to a V8 250 Daimler for quieter engine and road noise and leather trim.

lioneleast
Posts: 11
Joined: Thu Feb 25, 2016 8:47 pm

Re: V8 Saloon - too loud

Post by lioneleast » Fri Aug 17, 2018 5:34 pm

I can confirm that my 1964 saloon had under-bonnet sound absorbent material when new and it is still there. There was no sound absorbent material on the engine side of the bulkhead apart from round the heater box, which may have more to do with keeping heat in than sound out.

KV8
Posts: 181
Joined: Sun Mar 06, 2016 7:05 pm
Location: Cambridgeshire

Re: V8 Saloon - too loud

Post by KV8 » Wed Aug 22, 2018 10:21 am

Hi I have now lagged the exhaust from the manifolds back to the silencers. I have not lagged the flexible parts or the cross member.
This has brought about a small improvement in that the exhaust note is less sharp. However the noise levei is still high and I am now more convinced it is largely from the engine bay. This has led me to think a bit more about this area and I have a possible idea. However I want to do a bit more investigation, consultation of the manual and searching this and the old forum before posting on here. I this proves to be a possibility I will come back in a new thread focused on this item.

Meanwhile thanks to all for the contributions suggestions and observations on here.

H

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