I purchased some 3/4 inch noise reducing material and want to install it inside my engine compartment...is this safe...?
Meaning, when the engine is running would it not case the engine to run hotter...?
If you're going to install it only on one bulkhead, probably not significantly--if you don't reduce airflow into the engine space or around the engine. But if you're thinking about installing more than that, especially since...
The distance from the engine wall to the engine is about 2 inches right now...
I assume you're talking between the engine and one
bulkhead? So you'd reduce that to 1-1/4". I dunno... 1-1/4" isn't very much.
I am doing this because the engine is very noisy when inside the sailboat and it is running.
Two solutions to that: 1. Stay outside, 2. Use the sails, instead of the engine
I'm going to guess that the engine being in such a confined space in our boat, and we've much
more than 2", all around, is the reason Pearson used a kind of "Venetian blind" kind of wood thing between the quarter berth and the engine space on our boat, and pegboard between the engine space and the lazerette.
You can buy a relatively inexpensive indoor/outdoor digital thermometer set at Radio Shack. Secure the outdoor unit above the engine near the bulkhead in question. Reset the high/low temperature memory. Run things as they are through your normal routine. Note temp. maximums. Install sound-deadening materiel. Reset high/low temp. memory and do what you do again. Check difference.
Installing the sound-deadening material on one engine compartment bulkhead might not do much. I'm going to guess that much of the sound is transmitted throughout the boat via all of the engine-facing surfaces. Being inside the cabin when the engine is running is kind of like being inside the drum.