Soundproofing

[Steve Hansen]

What is the thickest sound proofing foam used in the engine compartment. That would be for a mark 1 m25xp. I see many using 1 inch foam. defender has a 1 1/4 to a 1 1/2 for only a few dollars more. Was going to order the 1 inch but if anyone had success with thicker I may give that a go.

[kh3412]

Just did mine you could probably use 1 1/2 for the sides but top and front would hit, with 1 inch not much room there. Infact the front or back of stairs you should reuse the plastic washer where the crank shaft sticks out.

[Noah]

I recently did mine and 1-inch is maximum in most places and more than efficient—considering that in our Mk1 boats the engine space is open/cut out to the aft cabin, so you can't insulate/block all sound. To cover all walls, etc. (obsessively), you will need more than one kit. Also, you will have to cut out a notch for the flywheel. Good news is:  it was a BIG improvement in sound blocking and looks, when completed (over my original flattened-out, degraded, crumbling insulation).

Edit:
I used their Sounddown spray adhesive, with self-tapping screws and fender washers (not stud kit)  to attach. You will also need extra mylar/silver tape that you can purchase elsewhere (cheaper) to cover all seams.

[Steve Hansen]

Looks like I found info in tech notes August 2008 Vol. 26, No. 3. Seems as though Ron suggested 1 1/4 inch at least for sides. looking forward to changing out old soundproofing. Crumbling mess. Thanks for the feedback.

[Noah]

Some pics of 1 in. Sounddown:

[Steve Hansen]

Thats a nice clean engine compartment Noah. Is the second from last photo the bottom steps? Looks like there is a notch cut into soundproofing for the shaft. Do the steps easily clear the shaft when putting steps back in place?

[Noah]

Thx. Yes, the steps panel does slide in with clearance however, I just need to be a bit careful when sliding bottom edge past flywheel that it doesn't catch on way down.

[Ron Hill]

Steve : Look in the Mainsheet Tech Notes for my article on Replacing the Sound proofing (w/pictures). As I recall it was 1 1/4 " that I got from Defender.  I cut it to size with a band saw!!

A thought

[Steve Hansen]

Ron Hill Thanks

[Ron Hill]

Guys : When redoing the soundproofing, here is a heads-up!!

On a M25/M25XP if any of the Aluminum sound proofing facing touches the unguarded temp connection on the top of the thermostat - you'll get goofy hi-temp readings on the engine instrument temp gage.

In a Mainsheet Tech note article, I recommended that you might slip a protective boot over that connector!

A thought

[Noah]

Ron— funny you mentioned this rubber boot and unprotected wiring shorting-out against the soundproofing  issue. So true!  I had a red rubber battery cover/boot over my engine temp sender connection wire terminal which had fallen and landed on hose below. It is shown in the circled portion of the attached photo. I later secured it back in position! 😎

[Noah]

Secured:

[Ron Hill]

Noah : I must complement you on the cleanliness of your engine compartment! Have to admit that mine looks almost the same. 
A clean engine and compartment make it easy to spot leaks and helps with cooling. Some of the other owners engine compartment pictures almost make me  !!

A thought

[mdidomenico]

this thread is very timely given my current efforts to rebuild the engine compartment...

it's sooo clean the engine and dirt become transparent... :)

[Phil Spicer]

   WOW!!! On your next trip to the great lakes would you make mine transparent also