Engine compartment insulation

Janky

New member
Satisfying offseason project completed! Since I bought the 2004 204SSi one year ago, the engine insulation has been literally falling apart. The boy and I scraped off the old, then applied a new sheet of UXCELL Car sound damper. I'm hoping this is one area where an automotive product can be used for the boat. https://www.amazon.com/dp/B01I4F0J76?psc=1&ref=ppx_yo2_dt_b_product_details

One word of caution - it's super sticky. Parts of it stuck to my fingers and ripped a tiny layer off of the material.
Overall, looks much better though!
 

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Janky

New member
I've only had it out one time, but no, it's about the same. If anything, I think it might be louder. I'm guessing the open foam that was there was better able to 'catch' the sound waves?
 

LAKETIME

Member
I've only had it out one time, but no, it's about the same. If anything, I think it might be louder. I'm guessing the open foam that was there was better able to 'catch' the sound waves?
Hi, Janky,

I have a similar problem with my 2004 Sunesta 252. I want to do something similar, but I'm a little concerned that the sound levels may not be as quiet as I could get them. I'd like to see if there is a way to get something closer to 'OEM'. Do you know if Chaparral has access to anything like that?

Dan
 

Janky

New member
Sorry, I do not know. I suspect an open foam insulation might provide better insulation than what I used. I'd look for that. Our engine compartment doesn't get that hot so heat shielding (the shiny stuff) is probably not necessary, IMO.
 

Denny

Well-known member
Gold Site Supporter
I know nothing about this product, but your thread caught my interest.

I searched the net ant came across this
There is no doubt that Dynamat is the best.

I was doing some work for a guy that worked for Johns Manville and when I asked him about sound deadening for my girl, he asked me what engine I had. He said different sounds, different sound deadeners, and he got me what seems to be working very well. The only thing that I here is the out drive singing and the wind. that was 25 years ago.
 
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LAKETIME

Member
Hi, Denny,

Thanks for your input!
Several years ago, I worked with a few products (I don't recall the names) to do some acoustic insulation for an American General H1 (Hummer) that I once owned. This made a significant difference, as the truck was pretty loud compared to most pickup trucks, etc.
One of the products was similar to Dynamat, and I was told that it was less expensive. It was a very sticky butyl rubber backed by a very thick foil (and very sharp at the edges!). On top of that, I used a very thin (a few millimeters) layer of a foam with coated paper backing, which had a very effective adhesive.
As I understand it, the purpose of the Dynamat-type of product was to stop the vibration/resonance of sound, and the foam layer added to the acoustic insulation. However, this was applied to the type of sheet metal that is common in the automotive industry, so I'm not sure how this would work in applying this to the fiberglass engine enclosure. Surely, these structural materials have different vibration/resonance qualities.
In addition, adding the weight of the Dynamat-type product might make the cover heavier, depending on how much is applied.
Fortunately, my Sunesta 252 is very quiet, most likely because of the Mercruiser Mag 350, which is remarkably smooth.
I'm thinking, as Janky said: "an open foam insulation might provide better insulation".
Hopefully, I'll find something that would be a great replacement.

Dan
 

Denny

Well-known member
Gold Site Supporter
Hi Dan, the stuff that is on mine is not pretty. It is about 1/2 " thick and looks and itches like fiberglass and has a light weight backing, and is similar to what they put on the under sides of the hoods on cars.
 
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