The noisy 4D61 rides again

[Vic K]

I know its difficult to get opinions from brother/sister/other Albiners, but here it goes. A few posts ago I brought up the subject of re powering and maybe trading the inboard for outboards. I've decided to stick with what I have. The old engine is running pretty good and just got the tranny rebuilt but there is still that 'noise' issue.
1. I had the engine mounts replaced and I swear the new mounts made the engine louder. Barr ( I believe that's the name) mount were installed. Im asking, "Can the engine mounts affect engine noise?"

2. I have been reading about noise blankets used on car engines placed directly on the engine under the hood. So I tried making one. First I placed two one inch tubes parallel and fore and aft to the engine spaced 22 inches apart and about level with the water fill. Over this I placed a engine blanket which I made from a movers pad. This was folded over and given it a healthy treatment of fire retardant. The "blanket" doesn't really come in contact with the engine and it's clear of the alternator belt. Heat tape was put on the exhaust elbow.
a. Ran the 'Mary Jo' this past Sunday for about three hours. Engine noise was greatly reduced. We could actually talk without yelling at cruise (6-6.5 kts). There was no increase in engine temperature. I was impressed enough to order a real sound blanket to try.
2. Also I'm installing a 10' length of flexible hose to move the air intake from the engine to another spot in order to get cooler air to the engine. I understand ( if it's on the internet it has to be true,right?) that if you divert the incoming air through several 90 degree turns you can decrease the noise made by the intake on a diesel.

Has anyone else tried the engine blanket approach or moved the air intake? Engines and generators are placed in small tight compartments so why would this be any different? If you want to get the engine you just lift if off.

Comments are more than welcomed, they are encouraged.

Vic

[Sprig1]

Hi Captvic what type of blanket did you get? Noise seems to be a big problem. The more I read it seems no easy answer. I am a new owner coming from a sailboat which is so nice when you turn off the engine and enjoy wind power. It looks like caulking and air tight seals are one of the main things. My problem is its to quiet big fuel problems. At least the weather is breaking and I can start to work on it. Good luck and let me know how it turns out chris

[Vic K]

I'll let you know how it works. It's now being shipped and I should receive it next week. The makeshift blanket I tried did a good job so I'm hoping this real acoustical blanket will be a lot better.

[don123]

I know its difficult to get opinions from brother/sister/other Albiners, but here it goes. A few posts ago I brought up the subject of re powering and maybe trading the inboard for outboards. I've decided to stick with what I have. The old engine is running pretty good and just got the tranny rebuilt but there is still that 'noise' issue.
1. I had the engine mounts replaced and I swear the new mounts made the engine louder. Barr ( I believe that's the name) mount were installed. I'm asking, "Can the engine mounts affect engine noise?"

I think they have a good deal to do with it

I'm not sure how your engine is mounted, but my boat is a 'pre-production' model - One of the first hundred or so hulls built and my 4D61 was rigid mounted to the engine beds on all 4 corners. Virtually no builder does it this way anymore

Repowering, my new Yanmar came with 4 new cushy rubber engine mounts (as all Yanmars do) which reduce vibration and noise a BUNCH. I was excited to see the difference that would make, but unfortunately due to the rigid stern tube attached to the bulkhead behind the transmission, I had no choice but to rigid mount my Yanmar as well . . . . at least the transmission end of it - I did leave the rubber mounts at the front of the engine. The stern tube won't allow for any movement of the engine, and rubber mounted Yanmars move around a good bit, which requires the stuffing box to be flex mounted to the stern tube and there just isn't any room for me to do that

Even so, the Yanmar will be a good bit quieter than the old Peugeot - It's a much smoother engine and the turbocharger reduces the overall exhaust noise by quite a bit. Haven't had her in the water yet and won't for a few more months - We'll see how it goes. I did a rebuild of sorts with the engine bay doors, adding some leaded noise reduction foam backed panels to 1 1/2 inches of foam on the bottom of the doors. I also had to swap the doors port for starboard as I needed the starboard side to open first as that's where all the daily checks on the Yanmar are

I guess whatever noise I end up with is just something I'll have to live with . . . . .

Don

[denchen]

I have been thinking along the lines of bringing the sound down on my boat.
I have a 4 cylinder 1800cc diesel engine on rubber engine mounts. The engine compartment is fitted where possible with 30mm foam with the lead sandwich, and in all fairness is not too bad but I would like to bring the noise down more.
Now I know the laws on sound transmission, and the laws on heat transmission are almost the same.
With this in mind I have been thinking on making `an overcoat` cover that drops and fixes (velcro) on the outside/top of the engine cover.
Just a thought.

[Vic K]

I've added the interlocking foam on the outside (over) the engine covers as well as the rest of the exposed deck it helps somewhat but the engine blanket made the big difference. I'm sure any crack you can seal in the engine covers will make a difference.

[Vic K]

Here are a couple of photos of the improvised engine blanket. One of the mounted rails and the other of the blanket

[Vic K]

FYI:Today I tested the new 'engine blanket' with a three hour run. Not only was the sound level reduced but the pitch was changed to a more pleasant tone. There was no problem using my cell phone running at cruise. There still has to be some nips and tucks to make it fit better but I am quite pleased with the results. The interlocking foam flooring I had was removed for the run. Don't believe I need it anymore as it added another level of hassle to opening the engine cover.

[Sprig1]

Hi glad it helped. Where did you get your blanket?

[Vic K]

Sprig,

I got it off Ebay from nasernm 2000. It's called the E2 and is 48" X 66". I still need to trim the 48" end so it will fit better and make a notch to fit over the exhaust hose on the port side. Also need a handle sewn in. The blanket is heavy and the handle(s) would help.
I treated the surface with a fire retardant even though the blanket doesn't touch the engine surface. I covered the exhaust elbow with a heat wrap just to play it safe.
Good luck.

Vic

Where are you located

[Don from Mystic]

Don - with the engine mounted as it is any problem with realigning the shaft?

[Sprig1]

Hi Vic I live on the eastern shore of Maryland near chestertown . Keep loosing posts somewhere. Iam a new owner of an 27 fc. Just starting to work on it and it looks like it needs most things done. Thanks for the information on putting the blanket on the motor

[Vic K]

Good luck Sprig. I finished redoing my 27 after nearly three years. I guess one is never completely 'finished'. When I got mine wet last October I didn't think it would take another six months to get to this point of finally having a good day on the water with her.
There's a lot of good information about redos on this site. If I can help in any way I'll be happy too.
Vic

[Sprig1]

Thanks for the encouragement. Congratulation on almost getting her done yes you are never done always something. Just about almost finished an Alberg 30 sailboat from 1967 . Then the wife and and I decided we where really power boaters. Tired of sitting. Hope this is the last boat. Enjoy your boat and have fun life is short. Thanks Chris

[rnummi]

I've just sat removed dead foam from beneath engine compartment covers. Have any of you replaced your sound/fire insulation underneath the covers and cockpit sole? Reading about "hood" blankets and sound deadening it seems that our young gen x friends driving boom boom wagons have it semi-figured out. How about an initial layer of dyna-mat followed by another layer of closed cell foam/aluminum (that was originally there). I'm no longer worried about getting it to original spec. I want Hinckley Picnic Boat soundproofing spec. I have a friend that can get all the dyna-mat in the world for next to nothing.....

What say you all?