Re-Power for Good Results

[prohor]

Sirs,
As soon I have lost battle against oil leak, smoke, noise and vibration on my Perkins 4-108, (20 years old, but 500hr only), re-engine is more or less agreed with myself. Beta 50hp, Beta 60hp, Nanni 50hp, Nanni 60hp are on top of my list. I believe leaks and smoke must dissapeare, but noise and vibration is most negative effects to be sorted. During last two seasons I almost doubled thickness of the insulation in engine bay, replace engine mounts and used Aquadrive with no significant improvements. Please, help me with a good advise as noise and vibration has limited my cruising range very much. Perfomance is also an issue.
Boat: 29' Trawler type motorsailor @ 16000Lb
Engine: Perkins 4-108 / Hurth 250 (2.72 : 1)
Prop: 20"x16"
Current max speed 5.7kn@3000
Current cruising speed 4.5kn@2300
Thanks
Anton & "Prohor"

[never monday]

I would fit something large and slow turning. All the engines you have listed are "high" RPM engines.

[James S]

Originally Posted by never monday

I would fit something large and slow turning. All the engines you have listed are "high" RPM engines.

That would be my thought as well.
Additionally have a look at you exhaust instalation...its can be the source of a lot of noise.
Isolation of the water lift and other portions of the exhaust system can make a noticeable improvement.

Its my understanding that with systems like your Aquadrive, you can install a bit softer engine mounts...I have no first hand experience with those systems...just what I've read.

[GordMay]

Originally Posted by never monday

I would fit something large and slow turning. All the engines you have listed are "high" RPM engines.

For example?

[delmarrey]

Originally Posted by James S

That would be my thought as well.
Additionally have a look at you exhaust instalation...its can be the source of a lot of noise.
Isolation of the water lift and other portions of the exhaust system can make a noticeable improvement.

Its my understanding that with systems like your Aquadrive, you can install a bit softer engine mounts...I have no first hand experience with those systems...just what I've read.

I would tend to lean towards the statements above. I'm installing a Pythondrive (same as Aquadrive, just shorter) because my mounts are so soft, which does seem to be more quiet then my old VW motor. And if the exhaust is mounted solid the noise will go throughout the hull.

500 hours is nothing on a diesel, It's barely broke-in. Oil leaks maybe just old gaskets and the smoke, depending on the color, could be stuck injectors as old as the motor is. Or is the smoke in the motor compartment?

One more thing. Check to see if any of the motor is hitting part of the hull. That will transfer noise as well.

[cat man do]

Originally Posted by prohor

Sirs,
Beta 50hp, Beta 60hp, Nanni 50hp, Nanni 60hp are on top of my list. "

If you can accept a 50 and would like a 60 how about one of these

TAD for Cummins 4B 3.3-M Engines - Cummins Diesel - Cummins Marine - Cummins 4B3.3M - 4B3.3M - Cummins Marine Diesel

Puts out 55hp at 1800rpm and NON turbo, unlike the nanni 60

[nhschneider]

I installed a Beta 90 into my 48' ketch last year and have been very happy with it. Beta Marine primarily uses a Kubota tractor engine which has an excellent reputation in the agricultural and construction industries. The marinized use of the engines could mean that they'll last forever.

The Beta 50 has a maximum RPM of 2,800 which I would not classify as a 'high speed' engine.

By the way, my brother just bought a boat that was originally equipped with a Lehman engine and the second owner replaced it even though it only had 200 hours on it.

Fair winds and calm seas.

[Boracay]

Are you sure you have the correct propeller for your boat/transmission engine?

20x16 is a big propeller and 16" is a lot of pitch.

I'd suggest checking carefully before making any major changes.

I seem to remember 3600 as max rpm for the 4108. If this is the case it may indicate that you are overpropped.

My experience has been that propeller calculations are oriented towards a lighter boat with lots of power and they did not give me correct diameter and pitch for a big heavy boat. I ended up having the pitch reduced to (from memory) about 12" (2:1 gearbox) and my diameter reduced from 22" to 20' for an 85hp engine.

There look to be many happy owners of the Perkins, but it is not a big engine...

[sabray]

I put one in replacing a 4-154 that had 6000 hrs. Very happy with that choice. Not sure I would do that with a motor that has so few hours.
But the cummins is a simple low rpm non turbo reliable with available parts.

Originally Posted by cat man do

If you can accept a 50 and would like a 60 how about one of these

TAD for Cummins 4B 3.3-M Engines - Cummins Diesel - Cummins Marine - Cummins 4B3.3M - 4B3.3M - Cummins Marine Diesel

Puts out 55hp at 1800rpm and NON turbo, unlike the nanni 60

[NCboatrx]

Originally Posted by never monday

I would fit something large and slow turning. All the engines you have listed are "high" RPM engines.

All these engines listed by Anton are based on Kubota diesels and all have a max RPM of 2,800 or 2,700. These are not as high reving as the comparable yanmar and volvo diesels. The Cummins also most likely are too large to fit in the Colvic's engine compartment.

[gonesail]

the lugger diesel is a low rpm and low vibration engine .. also volvo. not saying they are cheap.

[svcambria]

It is too bad that the engine has only 500 hours on it, but it has been out of production for what - 20 years? Replacement parts will be harder and harder to find. I had to replace a Volvo 21B with only 1700 hours because I couldn't keep it in proprietary parts...
Usual "rule of thumb" is 2 to 2.5 HP per 1000 pounds displacement. If you are looking at Nanni 60 HP, try looking at Nanni 40 HP, same revolutions but smaller, lighter, uses less fuel, naturally aspirated. Comes with a selection of transmissions including inclined ones (I repowered with a Yanmar where I first encountered inclined transmissions - 7 or 8 degrees from horizontal - so nice for keeping your engine "level").
And yes, it seems like you have an engine/prop mismatch. The advise I was given was to keep the diameter as large as possible and adjust the pitch (in your case, downwards).
Michael

[sabray]

I would call trans Atlantic dorsal. My 4 -154 was out of dare but a rebuild was not out of the question. Certainly was a consideration. My engine had many hours the labor to pull it although I dud it myself was extensive. For me the consideation was
the labor involved dissambling, the extraneous old parts, unknown maintence. I also read. Numerous stories of Perkins rebuilds that were okay but oil still leaked. I think stepping back looking at the whole. Or hole. And analyzing all the components would be wise. I could have dine differt minus the labor I put out an extra 4k for a new engine I love knowing it's there when I need it and so far no oil in the bilge.