Insulating the engine cover....

[TBarCYa]

My 2008 Maxume 1800mx has a fiberglass engine cover and the entire engine compartment is fiberglass. The engine noise is very loud and I noticed on the Sea Ray version of this boat, there is insulation on the inside of the engine cover to keep the noise down. What I'm looking for are suggestions on types of insulation to reduce the engine noise. Things I've looked at so far are the foam panels sold at some online marine vendors (sorry, I couldn't find it at iboats.com) as well as mass loaded vinyl (MLV) which is similar to dynamat used in cars as well as egg carton shaped foam panels. I believe the egg carton variety is what's on the Sea Ray but I only saw it briefly at a boat show and don't really remember what kind.

MLV is very heavy and isn't worth the weight penalty. The panels I found appear to be too rigid to conform to the engine cover and are a bit expensive since they're sold at marine stores. This leaves the foam panels but I'm not finding much information about temperature resistance or fire/flame resistance. Obviously, I don't want to sacrifice safety for quiet.

So, I'm looking for suggestions. If anyone has used a particular insulation (perhaps something I haven't considered) with reasonable success, please let me know. My plan is to do the cover and all of the sides of the engine compartment and behind the rear seats to eliminate as much as possible.

Thanks.

 

[H20Rat]

Re: Insulating the engine cover....

I've looked into it also, and came to the same conclusion. The stuff sold at marine stores is that expensive, it isn't a premium tacked on. It needs to resist heat, moisture, as well as flamability requirements. Any other foam you find isn't going to have all 3 of those, which is critical.

 

[Icyharp]

Re: Insulating the engine cover....

One the note of insulation one thing to remember is that when the manufactures started insulating the engines a new problem arised and that was vapor lock. Some of the newer boats have ways to cool the fuel, and Sea Ray is one of them.

 

[ryanr623]

Re: Insulating the engine cover....

One the note of insulation one thing to remember is that when the manufactures started insulating the engines a new problem arised and that was vapor lock. Some of the newer boats have ways to cool the fuel, and Sea Ray is one of them.

I second this. You better have a good blower system (cool air in, hot air out) if you're planing on insulating the engine bay.

 

[emoney]

Re: Insulating the engine cover....

If you're definitely going to use the insulation, check your local auto parts store. It will be quite a bit less than any marine store and the same application.