Re-Powering GB32 (1966)

[FF]

Is that a big deal? (no transmission but a new plate to, match my existing).

If you need to purchase a tranny , a commercial grade has many advantages.

The Twin Disc units have been made for a lot of decades so a rebuilt TD will cost way less than a new lesser unit , and usually last longer.

Like every part drive plates come in 2 -4 quality levels , use the better grade..

 

[Mako]

Personally I wouldn't go for an engine higher than a Tier 6 (non computerised) engine.

That must be a typo. What are you actually referring to?

 

[DavidM]

If the JD 6414 was marinized by JD or Lugger then ok. If not forget it.

Also is it significantly cheaper than $20K, the cost of a Cummins factory remanned 6BT. The remanned Cummins is virtually new with a full factory warranty.

David

 

[Keijo]

I just came across this old thread that I started when I was looking to re-power our GB32 and realized that I did not post what I finally ended up doing.


We re-powered with a new John Deere 4045TFM85. Turbocharged 125 hp M2 rated Tier 3. Fantastic engine - 7.5 - 8.5 knots cruising. Smooth and quiet (with sound insulation in engine room). 1.8 GPH at 7.5 knots, no smoke.



Not cheap - but it's boat.


"I spent most of my money on booze, broads and boats. The rest I wasted."
Elmore Leonard

 

[Irish Rambler]

Mako. In Europe the 'greenies' started pushing for cleaner diesels by making laws which forced the engineers to bring in advances in emission controls.
Each law was called a Tier, i.e Tier 1, Tier 2 etc.
The 'greenies' barely gave the engineers time to catch a breath before they introduced another tier until they reached tier 6.
After that it became impossible for the engineers to go further mechanically and so computerisation of fuel delivery systems, injectors, pumps etc was introduced as you will now see on any modern engine.
For a boat I would never accept any engine with computerised control.
They definitely work but indefinitely and I for one would not want to get caught out at sea in any weather with an engine having electronic problems.
As I stated above I have recovered a total now of 6 boats with engine fuel problems caused by electronic fuel systems.
An engine I would definitely fit if ever I were to re-engine would be the Mitsubishi S6T, extremely quiet and smooth, lightly turbo'd with lots of torque, best of all it has a timing chain not a belt and has 'wet' liners so any future rebuilds would be a piece of cake.
JD engines are not usually used here in Europe.
If you look at Europe today (February 2022) you will see the 'greens' have pushed Europe into total dependency on Russian gas and left themselves in a situation of blackmail.
I'm all for improving our climate, but our problem is overpopulation of African, middle and far Eastern countries.

 

[Irish Rambler]

Where possible of course you must support your country and buy American made engines but many Cummins are built in China and I'm not so sure about the quality of steel.
Kubota have a factory in the states I believe but above 110 hp they use an Italian Iveco engine.
Re-engining is a bit like getting married.
You want something as docile and quiet as possible and easy on the ear with no excessive vibrations but a real goer when you need a bit of action.
Which is why for a displacement boat I would choose the Mitsubishi S6T .
At around 4 litres its easy on the fuel and thinking forward a few decades if the 'greenies' get their way and ban fossil fuels being purely mechanically it will run on a veg oil/paraffin mix.
Of course boats are very personal things, whatever your choice.
p.s (sometimes its easier to get a divorce than re engining your boat).

 

[Mako]

Yes I agree that re-engine-ing is a tough subject, just as selecting the correct engine for a new-build is equally challenging, except for usually having a naval architect on hand to help with the selection process.

Trying to balance engine size, rpm, gear ratio and prop dimensions is a major exercise.

BTW I believe the quality of Cummins and Weichai engines coming from China are excellent, if you can go for mechanical.

 

[Irish Rambler]

It all depends on what hull shape you have to begin with of course, that determines the rest of the set up.
Personally I prefer a displacement/semi displacement hull but that's a purely personal choice of course. I prefer a load carrying hull with good seakeeping qualities. I did enough rushing around and 100 hour weeks in my working life and now I love to just bimble along and enjoy every moment with boat in gear and mind in reverse..
The last couple of boats I helped to design were displacement hulls with the Mitsubishi S6T on soft engine mounts coupled to a 7 degree down angle Borg Warner 72C 1:54 ratio to Halyard marine flexible shaft coupling, then an 1'1/2" shaft through a PSS shaft seal to a 19x21 Europoise 4 bladed propeller.
That gives 7 knots economical cruising and 9 at full throttle, with using the tides its easy to get a 10 knot overall speed and there's enough thrust for cruising up the river Rhine in Germany or approaching hydro electric locks. Both owners highly recommend them.
Of course it depends on many factors, if you are still working, how far you have to travel to your boat, what cruising grounds you prefer, are you solo or have a partner and the depth of your pocket.
I'll take you though my new build stage by stage if I win the Lotto .

 

[guy with a boat]

We re-powered with a new John Deere 4045TFM85. Turbocharged 125 hp M2 rated Tier 3. Fantastic engine - 7.5 - 8.5 knots cruising. Smooth and quiet (with sound insulation in engine room). 1.8 GPH at 7.5 knots, no smoke.

Sounds like a great solution. What RPM are you using at cruise speed?

 

[Keijo]

With our old Dagenham 6D engine we typically cruised at 1750 RPM which gave us a comfortable 7.5 knots.



With the new John Deere we typically cruise at 8.0 knots at 1800 RPM and occasionally go up to 8.8 knots at 2240 RPM for a short time as per John Deere recommendations (obviously a big difference in fuel consumption - but nice to have the option).


Over 400 hours on the new engine now and very happy with it.

 

[Keijo]

I should add that in my research I came across 5 GB 32's that had re-powered (most were woodies) and all re-powered with a version of the John Deere 4045.

 

[guy with a boat]

Nothing runs like a Deere.

 

[Mako]

How well do they vibrate at lower rpms, or are they counter-balanced these days?

 

[Keijo]

The 4045 is counter balanced and runs very smoothly. It idles nicely at 600 RPM. At about 1400 - 1475 RPM there is some noticeable vibration but we simply avoid that speed.



I added soundproofing under all the cabin floorboards in the engine room at can honestly same it's quieter and as smooth, if not smoother, than the old 6 cylinder (which was smooth enough).


Early on in the research we were able to see a Cummins 4 cylinder installation. Very noisy and lots of vibration. Eliminated that choice in seconds.

 

[Mako]

You may have hit this already, but is your 4045 an electronic or mechanical engine?

 

[Keijo]

Electronic. See my post of a few days ago.