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Post by kris on Feb 12, 2018 16:34:07 GMT
this is a picture of the diesel generator ive fitted in my engine room. its a bit louder than i had hoped for,i suppose running any engine in an unlined metal box is going to produce noise. i used to have a single cylinder lister spinning a 12v alternator in the same space. Anyway im wondering if its worth fitting a silencer into the exhaust system? if it is worth fitting one, id like one with bsp fittings on. unfortunately the exhaust is 1inch and the only silencers i can find are 1and half inch . so i would have to use adaptors, would this effect the use as a silencer?
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Post by Telemachus on Feb 12, 2018 17:50:18 GMT
Looks incredibly anti-social and selfish to me. But no surprise, of course.
The only good thing about the installation is that it would be easy to pour concrete down the exhaust skin fitting and into the engine, which is what I would do if I ever had the misfortune to be moored near you when you were running it.
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Post by JohnV on Feb 12, 2018 17:52:05 GMT
Kris, ASAP do 1" BSP silencers but of course they are not the cheapest people around ..... if you can get 1.25" or 1.5" at sensible price I would just use it with a couple of black iron threaded adaptors , to the best of my knowledge it wont make a scrap of difference Gazza will probably be along to say if I am right or wrong
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Post by phil70 on Feb 12, 2018 17:55:56 GMT
It shouldn't be too hard to get an adapter to go up from 1" to 11/2" and only guessing here but I would not expect the fact the silencer is bigger to make a noticeable difference Phil
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Post by kris on Feb 12, 2018 17:58:57 GMT
Kris, ASAP do 1" BSP silencers but of course they are not the cheapest people around ..... if you can get 1.25" or 1.5" at sensible price I would just use it with a couple of black iron threaded adaptors , to the best of my knowledge it wont make a scrap of difference Gazza will probably be along to say if I am right or wrong yes that's what I was thinking of doing. Do you think it will make a big difference having a silencer?
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Post by Deleted on Feb 12, 2018 18:04:21 GMT
I've got an old silencer for a vacuum pump at work, I'll look at it and see what size fittings it has, been so long since I looked at it I can't remember. I'll post the dimensions as well, if it's any good to you it's yours FOC, I'll let you know tomorrow. John is right, an increase in size won't bother it, it's not a highly tuned two stroke that needs the right back pressure and pulses to help cylinder scavenging Added, an absorption silencer will help no end, you won't get it as quite as a Panda Fischer job but it will be acceptable. You could consider keel/raw water cooling for the Genny in time, obviously there's a fair bit of work in that, would be neater than using the rad and fan and give you the option of a wet exhaust that will take the edge of very nicely indeed. With your current setup you will need a good bit of ventilation - not just for the engine but the generator won't like getting hot. It may well be worth fitting a bilge blower to get some positive ventilation thorough the engine hole.
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Post by JohnV on Feb 12, 2018 18:15:19 GMT
Kris, ASAP do 1" BSP silencers but of course they are not the cheapest people around ..... if you can get 1.25" or 1.5" at sensible price I would just use it with a couple of black iron threaded adaptors , to the best of my knowledge it wont make a scrap of difference Gazza will probably be along to say if I am right or wrong yes that's what I was thinking of doing. Do you think it will make a big difference having a silencer? on board probably not a lot. I would have though outside, there would be more noise from the exhaust than anything else. The generator looks as if it is on it's own sub chassis ..... did you rigidly mount that to the hull or did you put another set of engine mounts under it ? (as the sub chassis holds the generator/engine tightly together you can mount the whole thing on quite soft mounts, this reduces transmitted noise quite a lot.) It is hard to see from the photo but you also want a large flexi section in the pipe, the more flex the better. If you are getting a lot of noise coming through the hull you could also try putting some sound deadening panels stuck to the hull behind the engine The original generator I had in my engine room was not boxed and was a 1600 cc diesel driving a 12Kva alternator this was also quite noisy but after those mods (not the sound deadening panels) it was a lot better
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Post by kris on Feb 12, 2018 18:26:06 GMT
John those are definately the sort of things I was thinking of doing, so it's encouraging to here that it's worth doing.
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Post by kris on Feb 12, 2018 18:31:03 GMT
It has a large piece of flexi in it, it works perfectly.. It's mounted flexibly to a drip tray. It was originally mounted in a box, but the box was fire damaged and huge. I'll have a look for a silencer for a start.
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Post by Jim on Feb 12, 2018 18:32:38 GMT
John those are definately the sort of things I was thinking of doing, so it's encouraging to here that it's worth doing. Have you no spare boxes of sound absorbing material you can stack round the engine?
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Post by Deleted on Feb 12, 2018 18:35:42 GMT
It has a large piece of flexi in it, it works perfectly.. It's mounted flexibly to a drip tray. It was originally mounted in a box, but the box was fire damaged and huge. I'll have a look for a silencer for a start. As I say Kris, I've got something that may well do you. I'll post details tomorrow 🚢🔨👍🍻
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Post by kris on Feb 12, 2018 18:37:01 GMT
It has a large piece of flexi in it, it works perfectly.. It's mounted flexibly to a drip tray. It was originally mounted in a box, but the box was fire damaged and huge. I'll have a look for a silencer for a start. As I say Kris, I've got something that may well do you. I'll post details tomorrow 🚢🔨👍🍻 Thanks
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Post by Deleted on Feb 12, 2018 18:40:42 GMT
No problem, I've often looked at it and thought it would make a good silencer for a boat with a dry exhaust - they only reason it's not been outed! I've a feeling this lot made it many moons ago. www.franklinsilencers.co.uk/I went to tech with a lad from Franklin's, he was a sound lad.
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Post by Mr Stabby on Feb 12, 2018 19:08:01 GMT
John those are definately the sort of things I was thinking of doing, so it's encouraging to here that it's worth doing. Have you no spare boxes of sound absorbing material you can stack round the engine? I see what you did there.
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Post by Deleted on Feb 12, 2018 19:20:28 GMT
I once had a boat with a petter pj4 in it (main engine) the previous owner had welded a rangerover silencer into the system. Worked really well. If you can weld or have a friendly welder who doesn't need an awful lot of beer in exchange for work then maybe a vehicle silencer would do the job ?
My skin tank cooled Lister LPW3 generator has a small "Burgess" bsp threaded silencer on it.
From the photo it does appear that the generator is going to be shockingly noisy as it does not seem to have any silencer at all. Another option is to route the exhaust out vertically and put a vehicle silencer on the outside. Obviously a vertical exhaust either needs a flap cover or an owner who replaces some sort of lid to prevent rain damage.
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