sound proofing

[Crooked]

Hi All,
I'm thinking of putting some sound proofing in my 40hp 2 stroke. It's not really noisy but I reckon I can improve the noise that it does produce from the power head through installing some sound proofing material under the cowl.

There are specific products that are made for sound proofing (oil resistant etc) and I was thinking of gluing some of this under the cowl. Does any one see any issues with this, over heating? I will keep the air vents clear.

A cover may be an option but I'm not convinced these are effective at reducing noise.

Yes I know the answer will be BUY A 4 STROKE / ETEC! but I can't afford it.

cheers, Evan

[turtleshead]

Buy a 4 stroke

[Dan5]

I had a tohatsu 40 2strk and did the same thing ,the stuff i used was meant for engine rooms it was lead backed with 25mm foam rubber and heat shielded with milar and made absoultly no difference!So i did go and buy a fourstroke and now i'm on my third.Dan.........

[Crooked]

Yeah thanks, I knew the answers would be buy a four stroke.

But it's interesting that you have already tried this Dan, did it make no difference you think because much of the sounds comes from the exhaust outlets?

Or was it that the sound proofing was just ineffective, it is the same stuff that I was thinking of.

cheers, Evan

[FNQCairns]

I had a tohatsu 40 2strk and did the same thing ,the stuff i used was meant for engine rooms it was lead backed with 25mm foam rubber and heat shielded with milar and made absoultly no difference!So i did go and buy a fourstroke and now i'm on my third.Dan.........

Dan or Evan where does one get this stuff??

cheers fnq

[Crooked]

FNQ,
I've actually now relocated to Cairns, well Miriwinni actually, returned home.

I had a look at the Whitworths website and they sell it by the sheet, I haven't been to the actual store in Cairns yet but will do if I go ahead. It's listed under Engine/steering and then sound insulation.

cheers, Evan

[FNQCairns]

Hi All,
I'm thinking of putting some sound proofing in my 40hp 2 stroke. It's not really noisy but I reckon I can improve the noise that it does produce from the power head through installing some sound proofing material under the cowl.

There are specific products that are made for sound proofing (oil resistant etc) and I was thinking of gluing some of this under the cowl. Does any one see any issues with this, over heating? I will keep the air vents clear.

A cover may be an option but I'm not convinced these are effective at reducing noise.

Yes I know the answer will be BUY A 4 STROKE / ETEC! but I can't afford it.

cheers, Evan

No issues just keep the cowl air intakes clear, don't pack to tight around engine as it will slow air flow to carbs (harder sucking). You could always do bothe inside and outside, outside with cheaper foam wraped in material I might too!

Mine has no inside foam lining as it was flaking due to age so I got rid of it before it stuck a reed open or something, I don't think it's noisy enough now to be a problem anyway but I certainly know it is there, 90hp Yam 2st.

cheers fnq

[Dan5]

We ordered in about 30 or so sheet's through Darwin shipstores it cost about $8000 with glue and it also came with some stick on spike's and clips to hold it on the engine room wall's.Crooked i reckon most of the noise was still coming from the exhaust i'd be trying a cowling cover first myself OCA make good long lasting one's but are expensive or get a motor trimmer to knock one up.Dan....

[Crooked]

Thanks FNQ,
I don't have any inside lining either, just the fibreglass cowl.

I think it should be OK and I will keep the air flow in mind, as you say it's not really noisy but I sit beside it also being tiller steer, so I reckon I can improve it.

cheers Evan

[FNQCairns]

Thanks Dan an Evan (missed your first reply) Will look it up in the W catalogue. Dan got a spare 8k!! Do you think that could that be the same stuff as the Whitworths??

cheers fnq

[Crooked]

Yeah it's not cheap, it sounds like very similar material. A sheet 1m x 1.3m x 25mm thick (approx) was about $70, not including glue.

It's foil backed on one side and the really dense black foam, really heavy.

cheers, Evan

[Dan5]

I'm not sure mate i'd have to see some in the flesh the stuff we had was lead particle compressed backing and about 25mm thick grey foam with perforated milar heat shielding on top,so sort of a sandwich.Yeah it was'nt cheap but it did work on the big boat keeping the generators down to a dull roar mind you we carpeted the back deck also wich may have made the resination a bit quieter.I really think a out side cover is the way to go it also protects the cowling.Dan.

[FNQCairns]

Yeah it's not cheap, it sounds like very similar material. A sheet 1m x 1.3m x 25mm thick (approx) was about $70, not including glue.

It's foil backed on one side and the really dense black foam, really heavy.

cheers, Evan

Sounds good! I was looking at some other foam at one of the foam and rubber sells here it was foil lined one side but the foam was polyethelene (sp) the salesman said it would work fine but i was not convinced, Polyethelene is everyday plastic bag material so I didn't go ahead (good for cooling insulation I guess), would work fine on the outside in a cover though, was very cheap.

Will get some of the Whitworths stuff, let me know how you go if you do it first.

cheers fnq

[Crooked]

FNQ and anyone else who is interested,
I did buy some sound prrofing from Whitworths, lead backed, 25mm and lined with foil on the other side. It was also sticky on the lead backed side so just peel back the paper and stick on, it worked really well and flexible enough to bend around the corners.

I tried the motor today and it did make a difference. Of course it is a two stroke so with exhaust noise etc it is never going to be quiet, but it did take out the 2 stroke roar at WOT where the sound proofing was most noticable. In all I am happy with the result.

cheers, Evan