Re-Powering GB32 (1966)

[sunchaser]

Being offered for sale in the classifieds?

Beta has a pretty strong tier 3/4 line up of NA "light electronic" engines using proven blocks and transmissions. JD has largely abandoned that market. The last decade of emissions mandates has limited choices for those wanting simpler new marine engines in the 80 to 150 hp range.

 

[slowgoesit]

Our 1974 GB36 woodie was repowered with a Cummins. Never really needed the turbo, engine was underutilized for 7.5kts we generally traveled. Even more underutilized in a GB32. Don't expect to still get 1.8 gph at 7 to 8 kts. More like 2.5 gph. We burned 3 gph in the GB36 at 7.5 kts. Put on 1900 hrs in 2 years. No issues except normal maintenance, oil changes, fuel fuel filters etc. Good luck with whatever you decide.

 

[Keijo]

Was that a single 6B?

 

[slowgoesit]

Was that a single 6B?

Yes, single, turbocharged, no bow thruster. Having only had singles, I never knew a bow thruster was "required"! Could have probably gotten along just fine with about 80 hp.

 

[DavidM]

Here is an ad for a Cummins 4BT which is about 150 hp, asking $5,000.

https://boston.craigslist.org/sob/boa/d/mattapoisett-bt-cummins-diesel/6969614945.html

The 4 cylinder Cummins has significant vibration at low speeds so it is not as smooth as the 4 cylinder JD 4045 with balance shafts. But a whole lot cheaper and seems to be a complete package with a Hurth 630 transmission and control panel.


David

 

[Bill & Stella]

The three point mounts are to control torsional/radial vibration?
Are the aft mounts traditional bell housing supported?

Engine weight is better distributed using three mounts. With four engine mounts any rocking will seriously compress one mount transmitting vibration to the engine bed. With three mounts the engine usually rocks on two of the three mounts lessening conducted vibration.

https://photos.smugmug.com/COOT/i-SLRk7fF/0/c9b153eb/640/IMG_2940-640.mp4


Coffee cup test:

Four mounts-
https://photos.smugmug.com/COOT/i-3XMCmPT/0/110e1f20/640/IMG_2938-640.mp4


Three mounts_
https://photos.smugmug.com/COOT/i-7crxHbk/0/99ef2635/640/IMG_2939-640.mp4


You'll never see a four legged milkmaid's stool.


AFT mounts attached ti the bell housing.

 

[Ski in NC]

I've designed mount systems for 3cyl and 4cyl propulsion diesels and I do prefer to use 3-point mounts where possible. The low rpm rocking motion can be better isolated using 3-point. But on many engine designs it makes for complicated or strange bracketry to make it work. Sometimes worth it, sometimes best to go with 4-point, but be careful with spec'ing mounts, do that part right.

On a straight six, I just go with 4-point. They are smooth enough naturally. But getting the right mounts is important there too.

 

[Nomad Willy]

Originally Posted by Nomad Willy,
The three point mounts are to control torsional/radial vibration?
Are the aft mounts traditional bell housing supported?

 

[Mike Potter]

some ideas

Its important to size an engine so that it stays around 75 % rated as much as possible. not doing so will glaze the cylinder walls and not allow the exhaust gas temps to come up enough to burn off moisture.
the result will be wet stacking just like on low loaded generators.
if you can swing it money wise, taking advantage of electronic controlled high pressure common rail engines will really pay off.
They are easier to diagnose and repair, repairs are far less frequent, they are quieter and the torque curve throughout acceleration is way better than mechanical engines. not to mention they are much quieter and cleaner exhaust/less smell. your doing it right by moving slow and thinking.
consider: exhaust pipe diameter, seawater inlet diameter, shaft size. depending on the gear, you may have to change that and the torsional dampener as well. Nanni Diesel has not been mentioned in this thread which is surprising. They have been around for over 100 years and make very good marine engines not to mention competitive pricing. Leave yourself enough power to make it through troughs and inlets. Nothing wrong with a wood boat. if given the choice, thats what i would have. especially in the cold water where there is far less worry of toredoes and rot. Cummins, Deere and Nanni are the picks. The new 4045 goes up to 225 horsepower and is an extremely compact package. hope this helps some.
Bless you, Mike

 

[slowgoesit]

Forced to re-power. Considering Cummins 6BT vs John Deere 6068 TFM or 4045 TFM. Want 7 - 8 kts at 1500 - 1800 RPM's. Want an engine rated in that range. Any suggestions out there?


Keijo

If you are up for a road trip, and can figure out what to do with the hull, this might be an option:


https://houston.craigslist.org/boa/d/texas-city-trawler-yacht-40ft/6968759619.html

 

[Nomad Willy]

Mike Potter,
I agree mostly but there’s 5000 guys on this forum that don’t.
HaHa good luck.

 

[Mike Potter]

Been spending a quiet Sunday afternoon. wish i had not even looked at this. I'm sure you are right about the 5000 guys (and gals).

Agreement or non does not change the science or facts of the matter.
Our industry has made tremendous strides in the last decade or so.
I have no intent of mentioning what I do or where i am.
I have no points to prove or arguments to win.
This is why i read some things from owners and operators but near to never respond. I will leave that to internet tycoons and pros.
I just thought it might help someone who is getting bombarded with varying answers that cover all compass points.
Please allow me to rescind any ideas i submitted, I am not studied in the field of marine propulsion and possess no ties to any engine maker or dealerships.
Just trolling and sorry to have bothered anyone.
I saw some guy mentioned he has designed engine footings and various advanced technical things. advice is best taken from folks like that.
signing off and thanks

 

[Jeff F]

I'm with you Mike Potter.

I have a Cummins 6BT in my boat, and my average fuel consumption over the last few thousand miles has been very close to the 1.75 usgph cited by the OP. I go slow most of the time. Burble along happily for days at 1000-1200 rpm. I like the low rumble and appreciate the reserve power to get off a mud bank .

But I don't think that's the right replacement for the OP, even in the NA configuration. Too much power.

The OP has a 63 year old wooden boat that's probably been run at < 50 hp for it's entire life, and is not looking for more speed. None of the existing mechanics - shaft, prop, cooling, exhaust, motor mounts, fuel delivery, etc are going to be suitable for properly handling 150+ hp. I'd have some concerns about the structure and condition of the boat under more power. The WOT commissioning tests might get interesting :-(.

I'm not familiar with new offerings in the 50-75 hp range, but that's where I'd be looking for a replacement. With a small light motor there should be lots of opportunities to address NVH with good mounts and sound insulation.

 

[Bill & Stella]

I've designed mount systems for 3cyl and 4cyl propulsion diesels and I do prefer to use 3-point mounts where possible. The low rpm rocking motion can be better isolated using 3-point. But on many engine designs it makes for complicated or strange bracketry to make it work. Sometimes worth it, sometimes best to go with 4-point, but be careful with spec'ing mounts, do that part right.

On a straight six, I just go with 4-point. They are smooth enough naturally. But getting the right mounts is important there too.

Ski, LM and Cummins four cylinder engines are the worst. BTEA's not so bad. John Deere and IVECO four's have build in balance shafts and are fine.


I always specify Chushyfloat 55's and use a Timken thrust bearing and carden shaft on all the boats we build. Folks have said "it feels like an electric boat".

 

[Nomad Willy]

I was going to use Cushy Float mts but decided to use Australian engine mts pollyflhttp://pollyflex.comex.com that I think the active part is plastic .. a rubbery plastic called a polymer.

My thinking at the time was that the soft mounts like Cushy Float and Yanmar mts don’t absorb vibration or dampen it they just allow the movement but the movement isn’t reduced much and the rubber just bounces back. If you throw a rubber ball at the wall it comes flying back at you. Throw a lead ball at a substantial wall like concrete it will probably hit the wall and just drop to the floor. The fwd inertia of the ball gets absorbed. That kind of dynamics can reduce vibration but rubber is very limited.

 

[Keijo]

I've now had the opportunity to see and hear a John Deere 4045T in a Grand Banks 32 woodie (hull #18 - mine is #17, 1966). The engine is far quieter than the Cummins 4BT and although rougher at low revs than current engine, it smooths out to an acceptable degree at higher revs. The engine gave that boat 7.8 - 8 knots at 1800 - 2100 rpm.



I will now try to source the correct model of a JD 4045 (likely a new 4045 TFM85) to re-power our GB32.


Thanks to all here who contributed valuable information.


I'll post a summary of results when all is done (months from now).


Keijo (in Sidney, B.C.)

 

[DDW]

Its important to size an engine so that it stays around 75 % rated as much as possible.

This is why all three major pickup manufacturers have chosen to size their engines to run at perhaps 35% load nearly continuously. With millions sold per year and virtually none of the stated problems.

Yeah, I'm one of the 5000 .

 

[Comodave]

The JD 4 cylinder will be smoother than the Cummins 4 cylinder but it will still rock and roll at idle. However a wood boat will probably absorb the vibration better than a glass boat.

 

[sunchaser]

Mike
The TF annals are filled with engine loading discussions. Doubtful you'll find too many on TF running at 75% load, as measured by fuel burn. Primarily because it is not rational given the vessels we own that already have engines installed.

In a perfect world and the boat is being newly speced, maybe a fighting chance to design it that way, but why is the never ending argument. Especially in this day of electronic engines.

 

[Nomad Willy]

I agree w the run’um fairly hard theory and failed to get into the 60-70% load range.
But at 50% I’m very happy w everything.

Can’t relate to running at or below 35%. Diesel engines run too cold for that. And 75% seems really working hard. “Seems” is the operative word.

And re the above I’ve never heard of a manufacturer recommending 35% on a boat. Boat loads are way different than road vehicles.

 

[Capt Nemo]

Current engine is a Ford Dagenham 6D turbocharged. They stopped making them in 1967. Rebuilt in 2014, some parts very difficult to source, some parts not available. 860 hours on rebuild. Recently a valve snapped, valve guide broke, bent push rod and damaged piston. No one can explain how this happened. Zero confidence in engine. No logic in repairing current engine. Want to keep the boat another 10-15 years. Willing to repower with new or recon engine. Don't want a 60+ year old engine when I finally go to sell. Beta dealer is 5 minutes away. Want a smooth running, efficient and dependable engine. Of course it will cost me - I just want the right engine.

Hi Keijo

I have the engine you need
It is a 1981 Perkins 4 - 236 Diesel.
This engine has been completely rebuilt, with a BG Velvet Drive transmission.
$ 7350.00 Cdn. Will supply list of all new parts used in rebuild. This engine has 1.5 hrs. run-in time. Gauges included.
Will ship to you crated. Great deal.
You can email me
northchannel@msn.com
or call 705-248-1234 at your convenience
Thanks for taking a look

 

[FlyWright]

Hi Keijo

I have the engine you need
It is a 1981 Perkins 4 - 236 Diesel.
This engine has been completely rebuilt, with a BG Velvet Drive transmission.
$ 7350.00 Cdn. Will supply list of all new parts used in rebuild. This engine has 1.5 hrs. run-in time. Gauges included.
Will ship to you crated. Great deal.
You can email me
northchannel@msn.com
or call 705-248-1234 at your convenience
Thanks for taking a look

WOW!!! What a great engine. I LOVE this engine. I have twin 1977's and they just keep on running! They're efficient, reliable and cheap and easy to maintain....relatively. No 50 hr fuel pump oil changes here!

It just takes adding fuel, oil and externally mounted accessories to keep going fwd. None overly expensive on this engine.

Why was this engine rebuilt and who rebuilt it? How does it start? Got a video?

 

[SoWhat]

I've now had the opportunity to see and hear a John Deere 4045T in a Grand Banks 32 woodie (hull #18 - mine is #17, 1966). The engine is far quieter than the Cummins 4BT I will now try to source the correct model of a JD 4045 (likely a new 4045 TFM85) to re-power our GB32.

Many used/reman Deere 4045's for sale on machinerytrader.com

 

[Boat]

Diesel engines in 18 wheelers generally outlast diesel engines in pickup trucks. There's more to it than just the duty cycle but it's something to think about.

 

[rslifkin]

Diesel engines in 18 wheelers generally outlast diesel engines in pickup trucks. There's more to it than just the duty cycle but it's something to think about.

And ones in trains last even longer. Generally the bigger the thing the engine is going into, the less weight is an issue. So the engine can be a bigger, heavier, slower turning beast with a longer lifespan. But for a lot of our use-cases, an engine that would run 500k hours of boat duty without being rebuilt would be an engine that's just not useful for other reasons (like being huge, heavy and possibly less efficient).

 

[Keijo]

Well, I thought I was done with this thread but something has come up. In my search for an alternative to a brand new John Deere 4045TFM85 I have come across a re-built John Deere 6414 NA 135 hp engine. Any thoughts out there on that engine and how it relates to my particular situation?

 

[sunchaser]

Well, I thought I was done with this thread but something has come up. In my search for an alternative to a brand new John Deere 4045TFM85 I have come across a re-built John Deere 6414 NA 135 hp engine. Any thoughts out there on that engine and how it relates to my particular situation?

Is it a factory marine engine with transmission. If not, was it aftermarket marinized and if so by what group?

 

[Keijo]

I should know that by tomorrow. Is that a big deal? (no transmission but a new plate to, match my existing).

 

[sunchaser]

I should know that by tomorrow. Is that a big deal? (no transmission but a new plate to, match my existing).

A non marinized engine is a big deal (breaker) IMHO. An after market marinization then raises all sorts of questions. To keep it simple, if you can't find it on boat diesel's engine section be very careful.

 

[Irish Rambler]

My tuppence worth.
Price a rebuilt marinized John Deere, then price a marinization kit for the rebuilt engine.
Personally I wouldn't go for an engine higher than a Tier 6 (non computerised) engine.
Many people disagree but over the last 3 years I've acompanied 4 into port (who only had minimal revs and were afraid to be alone) all Volvo powered I might add.
As an aside many inshore fishermen around UK & Ireland I've spoken to seem to be in love with the JCB diesel engine. Apparently its very torquey and have great hydraulic pumps fitted (for thrusters and net hauling).