Deere 6068TFM

I have an urgent question; I think I already know the answer. I have the chance to buy a new, leftover John Deere 6068 TFM that is keel cooled. Can I change it ti heat exchanger cooling? If I can, I'm buying this motor.

I can't answer positively as I'm no Deere guy but you would need a heat exchanger of course but also a raw water pump. You may need a few other bits.

However, as you are now looking at PARTS purchases, not as a package, the cost of those items could negate the saving on the engine so get the specific model numner AND the engine serial number and ask or you may get a rude surprise.

There are many many suppliers of heat exchangers , as well as pumps that could push the sea water required to cool the engine.

NOT being locked into a Mfg can save big bucks at repair time.

Even wet exhaust manifolds ate aviliable from non factory sources.

MY favorite method of a good cheap engine is the Deere farm folks that sell factort rebuilds , with no core charge a couple of times a year.

For dry stack, and keel cooled simple boats , nothing is cheaper .

Give these guys a call and save a lot of wasted bandwidth:

Marine Engines, John Deere Marine Engine Sales

I happened to see my local Deere guy this morning (picking up some spare parts!) and mentioned your post to him and he said it should be easily done. Any Deere dealer has or can get the parts. As noted already here, third party parts are available as well. Since we have 2 6068 TFM's I can highly recommend the engine. We have almost 3,000 hours and have not had a single major issue beyond normal maintenance. My local Deere guy's estimate as to service life is a top-end rebuild at 10-12K hours. I may not live that long!

I agree. I wish I could keel cool but the boat is wet exhaust. I didn't get that engine, someone beat me to it. BUT I found a brand new John Deere 6141T bobtail of 120 hp@2200 rpm. Boatdiesel.com calculator says it will push my trawler.
DISPLACEMENT HULL
Hull Speed: 8.4 kts.
Power Required: 69.4 shp.
MAX PERFORMANCE
Available Power: 116.4 SAE hp ( 86.8 kW) @ 2200 RPM
Power Used: 69 SAE hp ( 51.8 kW) @ 1,852 RPM
Max Speed: 8.4 kts
Fuel: 4.1 US Gall/Hr (typical)
CRUISING PERFORMANCE
Cruising Power: 37 SAE hp ( 27.5 kW) @ 1500 RPM
Cruising Speed: 6.8 kts
Fuel: 2.2 US Gall/Hr (typical)
RECOMMENDED PROPELLER
Diameter: 31.1 in. Pitch: 24.5 in.
Blades: 3 Cupped: No
What say you guys? ....and thanks for the replies...I'm a planing hull guy and this is my first trawler.

Steve

You can keel cool with a wet exhaust.

Ya that makes sense Sunchaser, thanks. I just looked at a 42' widebody Kadey Krogan on Yachtworld, single screw 40,000 lbs. dry load with a single Perkins 135 hp. My hull is same round bilge, single, with wineglass transom 35000 lbs. I'm thinking this 120 hp Lugger/John Deere will push it. What are your thoughts? I'm about to hit the "send" button on a buy.

Hook it to a good tranny ,( Twin Disc is my favorite )and it sounds great. 32 is a good sized prop, can you spin it?

Question what ELSE will it be powering?

Mechanical refrigeration , water maker, Hyd power for windlass , or cruising generator ?

No problem ,except if all are run while at at top speed.

When new is the time to install a pulley with as many groves as the factory will sell you.


What price for a factory rebuild from the JD farm folks? Might be Half or less?

"You can keel cool with a wet exhaust." "

And you can do it with a dry exhaust manifold , with a bit of thought.

The new insulating blanket material in a custom fit will keep the ER at modest temps, and the manifold noise down.

FF; This is the Lugger nomenclature. I'm not sure which hp this engine has, really...or is it capable of all power ratings with certain changes to the motor?
Manufacturers
Rating OUTPUT HP/L RPM FIND SUITABLE
SAE HP kW Metric HP Gears Props
Continuous 120 89 122 17.7 2200
Medium 165 123 167 24.3 2200
High 175 131 177 25.8 2200
High 175 131 177 25.8 2200

6 Cylinder, 6.78 L, Turbocharged
Marine Diesel Engine Lugger

Graph didn't line up right.
Continuous duty 120 hp
Medium duty 165 hp
High duty 175 hp

FF; Also, refrigeration, windlass, thruster will all be electric, so no additional load on the diesel, and I'm getting a Northern Lights (Lugger motor) 7.5 kw genny and a large battery bank. I'm thinking that this motor might actually be 165 hp. It's a leftover new Lugger and I bought it last night. nervous! It is heat exchanger cooled. And re: the prop, I only have room for 26" wheel.
Thanks for your help.

Steve

That is more than enough power. Check out the installed HP on 40 to 47 Nordhavns for a comparable.

The trick will be designing the engine's cooling capacity to the transmission/prop/shaft combination to insure you can reach rated RPM without overheating. Go to a Lugger dealer and good prop shop to get this proper setup and then get a second opinion from a good source. Will the engine/transmission match up to your exisitng stringers?

Yes re: the stringers, they are big and beefy and had a Cummins 160-c six inline sitting on them. I would've rebuilt the cummins but no parts were available. There is a Northern Lights dealer within 15 miles of me, I plan to use them plus as I said, I want their genset so the engine room will be all Lugger. I too like Twin Disc gears. I did check out many 42' Kadey Krogans on yachtworld; they all had 120s and 135s. Good enough for me. Now to sift through the myriad of gears....

I only have room for 26" wheel.

You will need to figure the reduction gear required to load a 26 inch prop , and perhaps to at least a 4 blade ,or a 5 blade (big big bucks) to have the blade area.

Many books will have a nonograpg where a simple ruler can be used to work out prop diameter , shaft speed , power.

Use the low HP (cont duty) to figure your cruise speed , and see if you can use a high percentage of power use at that rpm, at say 1600 or 1800, and still be not over propped , and operate safely within the high (temp) hp setting on the pin..

The better percentage of the available power used at cruise translates to better fuel burn and longer engine life. You do not have to operate at 60% or so of total engine power , jyst 60% or better of the power available at your selected cruise setting.

Custom Marine Inc. - It's All About Performance - Header Applications, Tailpipes, Accessories is a possible source for a custom wet exhaust.

Thank you for the link, I bookmarked it. I use boatdiesel.com's calculator and the best numbers and calculator approval I get is with a 4 blade prop, 26" dia. with a 2.5:1 gear. It doesn't have 5 blade info. The cruise is 7.2 kts. @ 1600 rpm. 2.6 gals per hr. I can live with that. What do you think?

The cruise is 7.2 kts. @ 1600 rpm. 2.6 gals per hr. I can live with that. What do you think?

Sounds good , but run the numbers for the same prop at max 2100 rpm ? and see if the power required is above the temp "Hi" power output.

If its not you are OK if some clown runs on the pin in the future.

Otherwise you will need a red line on the tach to never operate over.

From the 24/7 operation hp graph , how much power is possible at 1600?

2.6 GPH is 40 to 50 hp , what percentage of rated power at 1600 is that?

I'll check

Deere Rebuilds

FF said:

There are many many suppliers of heat exchangers , as well as pumps that could push the sea water required to cool the engine.

NOT being locked into a Mfg can save big bucks at repair time.

Even wet exhaust manifolds ate aviliable from non factory sources.

MY favorite method of a good cheap engine is the Deere farm folks that sell factort rebuilds , with no core charge a couple of times a year.

For dry stack, and keel cooled simple boats , nothing is cheaper .

Click to expand...

How do you find the "Deere farm folks"? Thanks.

"How do you find the "Deere farm folks"? Thanks."

Deere farm machinery,
Google or yellow pages

I have the transmission you need

I have a spare Heavy Duty aluminum case Twin Disc Transmission in excellent condition with a 10 degree output flange that I was using in a 46 foot Custom Full Displacement Diesel Trawler.

It is a 2005 year model, so it is maybe 12 or 13 years old, but only has 400 hours on it. So like new inside.

It was bolted behind a John Deere 6068 & it worked great. Has a SAE bell housing # 3, so also fit Cat Diesels & John Deere Diesels, etc...

Twin Disc PT# MG-5050A.

This is a continuous duty transmission at 156 HP input or less & has a 1.8 : 1 ratio which was 1800 RPM equaled 8.3 knots for this boat with a 39 - 40 foot water line at 4 GPH & the transmission is so heavy duty that can handle up to 365 HP in M-5 usage in Pleasure craft.

I can send you the info if your looking for something like that.

PM me if you or any one else is interested.

I am located in Southern California.

Thanks.

Alfa Mike