Cummins 6BT5.9M (220hp)

[BernieG]

Hi folks,

Looking at a boat with a 3500 hr Cummins 6BT5. Looking around they seem reliable enough with upgrades to the water pump. However, a couple of questions:

1) What would an overhaul likely cost (ballpark)? Anyone had experience of doing this?
2) Can the HP be upgraded to say 250hp or even 270hp?

Cheers
Bernie

 

[HopCar]

Sorry I can't answer your questions but I'd like to know what upgrade you can do to the water pump. I'm not fond of the Sherwood pump on mine.

 

[BernieG]

Possible pump replacement

Not sure but see this discussion: Cummins 6BT5.9M Engine

Sorry I can't answer your questions but I'd like to know what upgrade you can do to the water pump. I'm not fond of the Sherwood pump on mine.

 

[C lectric]

Go to Boatdiesel.com and pay the $25.00 and read.
Also look up Seaboard Marine Custom Cummins Marine Diesel Repower Specialists | Seaboard Marine

and read what is on the site. Lots about how to look after that engine.

Seaboard offers a replacement raw water pump which many B.D. members have used and are happy with.
That engine, if looked after and propped properly, will last many hours yet, often reaching 10,000. Of course it does need looking after. One of the best engines around. Of course any engine can be wrecked if not setup and looked after properly.

As for 20 or 30 hp increase it's not going to do much. It sounds better than the reality. Pose the question on B.D.

 

[HopCar]

"Not sure but see this discussion: Cummins 6BT5.9M Engine"
Is it the "cheese cake bronze" comment that has you worried?
He's nuts. The only thing wrong with the Sherwood pump is you have to remove the hoses to change the impeller. There is an aftermarket replacement pump that fixes this on the larger engines but I don't know of one for the 6BT5.9M.

 

[DavidM]

Tony's redesigned water pump will not work with the Cummins 220, only the 330/370.

Upgrading horsepower won't be easy. At the minimum it would take adding a sea water intercooler, changing the turbo, changing or recalibrating the injection pump, maybe changing the injectors, maybe upgrading the cooling system, etc, etc.

OTOH the Cummins 220 is a great engine. If it had been installed on as many trawlers as the venerable Lehman 120/135 was, I am sure today it would be considered a more solid engine.

David

 

[O C Diver]

Good motor, had one in my charter boat. Nothing wrong with the Sherwood pump. Chesapeake Bay watermen have used them for decades. Not uncommon to get 10, 000 hours out of them with minimal maintenance. They are not a sleeved motor. So rebuilding doesn't get you new liners unless you have the block bored and press in sleeves.....which is done. Engines are still sold from Cummins as a factory reman. This means a new engine with one used part on it.

Ted

 

[dwhatty]

Put A SeaMax pump on our Cummins 330 6BTA 5.9 three years ago after the Sherwood developed a leak and the wear plate kept getting chewed up. The new pump has been trouble free and the impeller is much easier to change.

SMX 1730 Cummins Seawater Pump - Direct Sherwood Replacement on most early 6BTA & all B & C series Diamonds

 

[Marlinmike]

From the rebuild cost perspective you can contact Cummins and get a price for a reman'ed, come with warranty and is good to go, quite reasonable actually, but like others have said the 220's are very long lasting by design.

 

[Mule]

Does your 6BT have 2valves per cyl or 4? Mine 6BT has 4 rated 250hp. No inter cooler. Not sure 30hp would be worth the effort.

 

[sunchaser]

Bernie

What type and model of vessel are these engines installed? What RPM and boat speed does the current owner normally cruise?

As Celectric says, post your questions on boatdiesel but add lots of details on current setup, condition, pictures and past and future intended boat/engine operating conditions.

As stated by other posters, the Cummins 220 remains the engine of choice for many, so you may have found a winner. The devils in the details.

 

[BernieG]

Thanks for the good advice everyone. Its in a 2000 Nordic Tug 32. Broker suggests a top end of 12 knots and I was hoping for a little more, and looking at options as I know the later models have larger engines.

 

[timjet]

Just my opinion but as the owner of 2 330 B's I would stick to the non turbo'd 220 hp. Simpler design and probably bullet proof.

Cost for a Cummins certified 330 B reman is $17000 plus the core plus install costs. Don't ask me how I know.

 

[O C Diver]

Just my opinion but as the owner of 2 330 B's I would stick to the non turbo'd 220 hp. Simpler design and probably bullet proof.

Cost for a Cummins certified 330 B reman is $17000 plus the core plus install costs. Don't ask me how I know.

220 hp is tubo'd. The 135 / 150 hp was a natural, but short lived in the market. As you went up from 220, they added after cooler and a fuel cooler.

Ted

 

[bligh]

Thanks for the good advice everyone. Its in a 2000 Nordic Tug 32. Broker suggests a top end of 12 knots and I was hoping for a little more, and looking at options as I know the later models have larger engines.

At 12 knots youll be burning through fuel pretty quick. If I run my 37 wide open at around 16 knots, I'm burning 25 gallons per hour on my 6bta 330 hp ($100 plus per hour). I have run my 37 at top speed and it sure is a beast. The boat's bow points straight up, it throws a huge wake, sucks fuel and doesn't really go that fast. I have yet to see another NT running at flank speed, ever.
So while you think you want to upgrade it now, you'll probably find you will only run at 7-10 knots or so to save fuel but you will be able to go faster if you have to. If speed is a concern to you, you are looking at the wrong boat.
Personally, I would be happier with the 220 on my 37. Less headaches with the turbo, better fuel consumption, runs cooler, less maintenance, etc. They only install those big motors because they can and people buy them.
As for the cost install a new remanned engine, I would think you are looking at between 12-16 thousand dollars to do it.

 

[stone beach]

to answer point 2 of the o.p., the basic cummins engine is the same in most hp versions up to 300, its all the peripheral stuff added that squeezes out more power, so from that aspect it is "possible" ..... but it would be unwise

to respond to post #12, adding hp will hardly change the speed of tug form 32' hull, it will just increase the fuel used, if you want to go fast you are looking at the wrong boat

3500 hrs (if that is correct) is a long way off when an overhaul should be required....if it needs an overhaul then there is something wrong with the installation or with the hourmeter reading. measuring crankcase blowby under full load will tell you if an overhaul may be required

 

[High Wire]

to answer point 2 of the o.p., the basic cummins engine is the same in most hp versions up to 300, its all the peripheral stuff added that squeezes out more power, so from that aspect it is "possible" ..... but it would be unwise

to respond to post #12, adding hp will hardly change the speed of tug form 32' hull, it will just increase the fuel used, if you want to go fast you are looking at the wrong boat

3500 hrs (if that is correct) is a long way off when an overhaul should be required....if it needs an overhaul then there is something wrong with the installation or with the hourmeter reading. measuring crankcase blowby under full load will tell you if an overhaul may be required

How does one measure blowby? First time I've seen that mentioned anywhere.

 

[DavidM]

How does one measure blowby?

Blowby is exhaust gas that gets by worn rings and valve guides and into the crankcase. There is a vent for it. Some people have installed an Air Sep in the vent to catch the oil entrained and recycle it. A better idea is to use Sbmar's Envirovent device.

Cummins has published a procedure for accurately measuring blowby on their engines and gives new and worn specs. It consists of installing a temporary orifice in the vent tube and measuring the pressure drop across the orifice. More pressure drop equals more cfm of blowby. If anyone wants a copy, send me a PM with your email address and I will send you the procedure.

You can do a quick and dirty test by opening the oil fill cap, running the engine up under load and put your hand over the opening. If you feel a rush of pulsing gas that pushes your hand up, you have significant blowby.

David