Soundproofing the engine bay

[Frankieboy]

Has anyone had any experience with soundproofing engine bays?

What is the best way to do it? I gather some kind of lagging.

Cheers

Frank

[alan_fincher]

Lots of previous threads on this, but in my view you cannot beat the proper sound deadening sheet materials that are a mixture of foam densities, but with a "lead like" layer in them too.

 

Not all are of the same quality, but the best I have seen, (but also one of the more expensive), comes from TW Marine.....

 

TW Marine Link

 

Not particularly cheap. The Aquafax / Midland Chandlers sourced stuff does not have the same foam density, nor as substantial a sound deadening layer.

 

Personally I'd forget so called self adhesive varieties, (which stay stuck sometimes, but not always). If you buy the stuff that doesn't have a glued layer, but stick instead with Evostick, in large amounts, it will definitely stay stuck, (and you'll be too "high" for days to care if it doesn't! )

[grandbanks]

Halyard Marine are specialists in this field:

http://www.halyard.eu.com/NoiseVibrationRe...nMaterials.aspx

[Machpoint005]

Start by making sure the deckboards fit properly, and mount them on rubber strips or similar to prevent them from acting as a soundboard. Make sure he exhaust silencer is effective. Then by all means use expensive sound-absorptive treatment. But if the deckboards don't fit, you are wasting time, effort and money.

 

 

By the way, you're not going to 'soundproof' it in the sense of waterproofing: waterproof means no water gets in, soundproof doesn't mean no sound gets out. But you can noise-reduce it.

[Frankieboy]

Start by making sure the deckboards fit properly, and mount them on rubber strips or similar to prevent them from acting as a soundboard. Make sure he exhaust silencer is effective. Then by all means use expensive sound-absorptive treatment. But if the deckboards don't fit, you are wasting time, effort and money.

 

 

By the way, you're not going to 'soundproof' it in the sense of waterproofing: waterproof means no water gets in, soundproof doesn't mean no sound gets out. But you can noise-reduce it.

 

 

Noise reduce is what Im planning. It's not hugely noisy but at the moment there is no sound proofing in there so I figured if I can have a little less noise then it may be worth the effort.

 

 

One other question....Is there any proofing materials to use / avoid on the off chance that they may get damp (really just the sections that meet the hull base)?

[Machpoint005]

One other question....Is there any proofing materials to use / avoid on the off chance that they may get damp (really just the sections that meet the hull base)?

I wouldn't be too worried about damp, but think carefully about oil spray/oil mist inside the engine bay - if that soaks into the absorptive lining materials, you might have a fire waiting to happen. A faced material is always going to be a better idea.

[Guest User]

A couple of isseues to consider .... Is it a cruiser stern or trad/semi-trad ? .. also is it an air-cooled engine ?

 

I've recently done a cruiser-stern aircooled engine bay, or rather just the deck boards with pukka sound deadening sheets as mentioned by others.

 

It doesn't make it completely quiet; a lot of the "sound" is transmitted via the hull as vibration because the engine is direct mounted and not on rubber mounts. Also it simply wasn't feasible (limited accessibility) to line the walls of the engine bay. Plus, as an air-cooled I didn't want to impede air flow nor over-insulate the engine bay. However, the sound deadening on the underside of the deck boards has made a significant improvement ... the "oooh its nice when you switch off" feeling has gone, as its now possible to have a conversation without having to raise your voice and quite a lot of the edge has been take off the engine noise ... on balance I'd say it was definitely worth it

[Lee J]

A couple of isseues to consider .... Is it a cruiser stern or trad/semi-trad ? .. also is it an air-cooled engine ?

 

I've recently done a cruiser-stern aircooled engine bay, or rather just the deck boards with pukka sound deadening sheets as mentioned by others.

 

It doesn't make it completely quiet; a lot of the "sound" is transmitted via the hull as vibration because the engine is direct mounted and not on rubber mounts. Also it simply wasn't feasible (limited accessibility) to line the walls of the engine bay. Plus, as an air-cooled I didn't want to impede air flow nor over-insulate the engine bay. However, the sound deadening on the underside of the deck boards has made a significant improvement ... the "oooh its nice when you switch off" feeling has gone, as its now possible to have a conversation without having to raise your voice and quite a lot of the edge has been take off the engine noise ... on balance I'd say it was definitely worth it

 

Hello Graham,

 

What type of soundproofing did you use?

 

Lee

[Guest User]

I'm afraid I don't know the make, but I think you can get them from quite a few places, I picked mine up secondhand at Beaulieu boat jumble at a very good price .... the sheets are about 30 mm thick in total (there is a thinner version), backed with a rubber layer about 1-2 mm thick, then its a dark grey foam which sandwiches another rubber layer about 1-2 mm thick and its faced with a silver woven material. It's very heavy stuff. It's not self adhesive and there was a debate in another thread on here about how to attach it, I didn't fancy glueing and ended up using stainless screws and washers (into wooden deck boards).