Hospital Silencers

[Badger]

Hi, I know their have been discussions on hospital silencers before. I wondered if anyone has fitted one to a Perkins Prima diesel?. I am taking my Prima out soon for a rebuild. It sits in my cruiserstern narrowboat, and I have allways wished it was quiter. It has quite a small silencer, and I wondered if fitting a 30 x 12" silencer box would make a big difference. It is hard to know if the noise is just engine noise as opposed to exhaust noise. I did fit acoustic panels around the walls and roof of the engine room years ago,but I don't think they made much difference.I would be interested in hearing other opinions ?.

Badger

[Proper Job]

If you stand a little way from the exhaust exit. is there a discernible noise from it?

 

If yes, a hospital silencer may help.

 

Most of the noise from the engine usually comes from the mechanical noise of operation rather than the combustion process. Sound proofing around the engine and ensuring that the engine is well maintained is the answer to those type of noises.

 

The fact that your are about to rebuild it would indicate that its a tad more rattly than it should be?

[Badger]

If you stand a little way from the exhaust exit. is there a discernible noise from it?

 

If yes, a hospital silencer may help.

 

Most of the noise from the engine usually comes from the mechanical noise of operation rather than the combustion process. Sound proofing around the engine and ensuring that the engine is well maintained is the answer to those type of noises.

 

The fact that your are about to rebuild it would indicate that its a tad more rattly than it should be?

Yes you do get a deal of noise from the exhaust. Infact when it is tied on the mooring, there is a wooden stake directly in front of the exhaust port (about 3" away). When it blows against that it makes a din, but i guess it would ?. I am really only taking the motor out because the cambelt has never been changed, and it is getting a bit smokey when waiting in locks with the exhaust port up against the lock wall.

 

Badger

[international_boatbuilder]

If you stand a little way from the exhaust exit. is there a discernible noise from it?

 

If yes, a hospital silencer may help.

 

Most of the noise from the engine usually comes from the mechanical noise of operation rather than the combustion process. Sound proofing around the engine and ensuring that the engine is well maintained is the answer to those type of noises.

 

The fact that your are about to rebuild it would indicate that its a tad more rattly than it should be?

 

 

Excuse me if I am wrong, and hey even I can be, the majority of the noise from a diesel engine is from the combustion process.

 

This can be muffled by good sound insulation and indeed a good hospital silencer package. Engine being well maintained is of course essential but really has no relevance to the topic

[Proper Job]

Excuse me if I am wrong, and hey even I can be, the majority of the noise from a diesel engine is from the combustion process.

 

This can be muffled by good sound insulation and indeed a good hospital silencer package. Engine being well maintained is of course essential but really has no relevance to the topic

The most noise from any internal combustion engine is due to the combustion process (ie.exhaust noise).

 

However, the point I was trying to make to the OP was that if he already had a silencer fitted (as his does and most engines do), just check (before investing in a larger hospital type silencer) that the noise was in fact exhaust noise and not general engine noise.

 

He subsequently confirmed that it was in fact a noisy exhaust. If that is the case, then he could benefit from the fitting of a larger hospital type silencer.

 

A well maintained engine also has a great deal of relevance to the topic as the OP advised that he was about to remove the engine for a rebuild. A worn engine emits a lot more mechanical noise/vibration than a well maintained non worn engine.

 

It could well have been the case that once the engine had been rebuilt the general engine noise level could have been significantly reduced.

 

As it happen, the OP subsequently advised that the 'rebuild' was probably only going to consist of a cam belt change and maybe a top-end overhaul/work on the injectors to try to reduce smoke when ticking over at locks.

[Badger]

The most noise from any internal combustion engine is due to the combustion process (ie.exhaust noise).

 

However, the point I was trying to make to the OP was that if he already had a silencer fitted (as his does and most engines do), just check (before investing in a larger hospital type silencer) that the noise was in fact exhaust noise and not general engine noise.

 

He subsequently confirmed that it was in fact a noisy exhaust. If that is the case, then he could benefit from the fitting of a larger hospital type silencer.

 

A well maintained engine also has a great deal of relevance to the topic as the OP advised that he was about to remove the engine for a rebuild. A worn engine emits a lot more mechanical noise/vibration than a well maintained non worn engine.

 

It could well have been the case that once the engine had been rebuilt the general engine noise level could have been significantly reduced.

 

As it happen, the OP subsequently advised that the 'rebuild' was probably only going to consist of a cam belt change and maybe a top-end overhaul/work on the injectors to try to reduce smoke when ticking over at locks.

Thanks Proper Job, Yes I think I have come to the same conclusion. I am going for a major rebuild. I will wait to see what difference (if any) that makes to the sound levels before I contemplate the exhaust further.Traders I have spoken to,say that a large hospital type silencer will make a significant difference to engine noise levels. On the other hand, they would say that wouldn't they.!.

 

Badger