Neil2 Posted May 27, 2017 Report Share Posted May 27, 2017 I want to beef up the lagging of my exhaust system in particular the hospital silencer. I know you can get rolls of 25mm lagging but ASAP eg only seem to sell it in minimum 7m lengths. I'll hunt around the boatyards if need be but does anyone know if/where you could get a short length of this stuff? Link to comment Share on other sites More sharing options...
bizzard Posted May 27, 2017 Report Share Posted May 27, 2017 10 minutes ago, Neil2 said: I want to beef up the lagging of my exhaust system in particular the hospital silencer. I know you can get rolls of 25mm lagging but ASAP eg only seem to sell it in minimum 7m lengths. I'll hunt around the boatyards if need be but does anyone know if/where you could get a short length of this stuff? Hospital silencers are usually pretty fat. 7 mx25mm might not be enough by the time you've done the half width overlap. Link to comment Share on other sites More sharing options...
Chewbacka Posted May 27, 2017 Report Share Posted May 27, 2017 I would look to use 2" wide lagging tape as I find 1" a bit fiddly to wrap in confined spaces. Link to comment Share on other sites More sharing options...
Neil2 Posted May 27, 2017 Author Report Share Posted May 27, 2017 2 hours ago, bizzard said: Hospital silencers are usually pretty fat. 7 mx25mm might not be enough by the time you've done the half width overlap. It's 25mm thick - and either 300mm or 600mm wide, IIRC. A roll of this stuff costs about £500. Obviously aimed at big seafaring boats but the 600mm would just fit snugly around my big silencer between the supports. I think I may have to trawl (sorry) round the bigger boatyards to find an offcut. Link to comment Share on other sites More sharing options...
smileypete Posted May 27, 2017 Report Share Posted May 27, 2017 Why the need to wrap the silencer itself? Link to comment Share on other sites More sharing options...
Neil2 Posted May 27, 2017 Author Report Share Posted May 27, 2017 1 hour ago, smileypete said: Why the need to wrap the silencer itself? Bukh engines are notorious for smoking especially when lightly loaded, one of the reasons being the low exhaust temperature, the fumes just don't get burned off. I reckon that by insulating the entire exhaust from the manifold will help to raise the temperature and reduce the smoke. I don't think it's a bad idea to reduce the heat dissipated in the engine room either. Link to comment Share on other sites More sharing options...
smileypete Posted May 28, 2017 Report Share Posted May 28, 2017 (edited) Tony Brook is da man for engines. But what colour is the smoke? That can help diagnose the problem. I'm no expert but would have thought lagging the silencer would make little difference to engine smoke, apart from making it a little warmer. I doubt anything would 'burn' as such in the exhaust unless there's a catalytic converter. Edited May 28, 2017 by smileypete Link to comment Share on other sites More sharing options...
Chewbacka Posted May 28, 2017 Report Share Posted May 28, 2017 On 2017-5-27 at 19:14, Neil2 said: Bukh engines are notorious for smoking especially when lightly loaded, one of the reasons being the low exhaust temperature, the fumes just don't get burned off. I reckon that by insulating the entire exhaust from the manifold will help to raise the temperature and reduce the smoke. I don't think it's a bad idea to reduce the heat dissipated in the engine room either. By the time the gasses get to the silencer they will probably be too cool to burn any smoke, so insulating it will make little difference to smoke. I do know that exhaust gasses can be more corrosive the hotter they are, but you do want the silencer hot enough to avoid condensation internally as that is also corrosive. It is also my understanding that the hotter the exhaust gasses are the more noise the exhaust will make, so it will be interesting to see if lagging your silencer gives an overall improvement in smoke, noise and silencer life. Link to comment Share on other sites More sharing options...
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