Cummins diesels

[rslifkin]

I’m not really thrilled with the 300hp rating. These engines were made for 200-250hp. Higher hp=less life. That being said they are great engines. Marinized variations can vary depending on as others have mentioned exhaust. Get them checked out. If they check good I wouldn’t worry about them to much. Btw you can get the hp reduced pretty cheaply. If the engines have the parts ie crank, rods, and pistons to be set at 300 would pick up a lot of life hours at 250, or even 275. Keep in mind that could require a prop change. If not planning on spinning them up in the very high 2k range you will be fine. I’d shoot for a hull speed rpm around 1,500-1,600 cruising around 2,000 wouldn’t take wot passed 2,500

That seems pretty conservative considering the later 6BTAs came cranked up to 370hp at 3000 rpm on the high end and provided they're not run wide open all the time, they're not known for being time bombs even at that rating. A 300hp rating wouldn't worry me provided continuous cruise power is at a reasonable level. Cummins was willing to offer a medium duty rating (rather than intermittent or high output) up to 250hp at 2600, so I'd figure cruise power on a 300hp should be kept somewhat below that, probably in the 200 - 220hp range for good lifespan.

 

[jrhodes777]

Cummins Diesels

We have 2 6BT 5.9 on a 1988 Brand Banks. Very happy with these engines! These are the 210HP turbo charged non after cooler version. 3500 hours and they don't burn a drop of oil and oil analysis results continue to be excellent. What we really like is that they are straight six leaving lots of room to perform maintenance in the engine room. Secondly parts are easily available.

 

[Boatingbill]

That seems pretty conservative considering the later 6BTAs came cranked up to 370hp at 3000 rpm on the high end and provided they're not run wide open all the time, they're not known for being time bombs even at that rating. A 300hp rating wouldn't worry me provided continuous cruise power is at a reasonable level. Cummins was willing to offer a medium duty rating (rather than intermittent or high output) up to 250hp at 2600, so I'd figure cruise power on a 300hp should be kept somewhat below that, probably in the 200 - 220hp range for good lifespan.

Indeed. I have a Dodge cummins putting out nearly 600hp. Will it last? Hell no! Is it fun to drive? Hell yea! Point is there is a time, and place for everything. I was just offering up my 2 Lincoln’s as to what my thoughts were on the situation. LOL Btw my old 903’s are 2 1/2 times the displacement and only 240hp. However the current 903 in the military bradly is 750hp. Avg. life at 750hp maybe 1000 hrs avg life at 240 most likely near 20,000 hrs. Anyway I’m not here to be a butt head, or hijack anyone’s thread. If any of my comments were offensive I apologize.

Milk toast answer: yes the 5.9 cummins should make for good engines in your boat. LOL

 

[MOJO]

MOJO (www.mvmojo.com) has a 6BTA-M Cummins rated at 250hp at 2,500 rpm. We have almost 4,200 hrs on her and she just keeps purring along. I typically run her at 1,500 to 1,600 rpm to cruise at 7.5 - 8.0 kts. Nice, fuel efficient diesel. I've read that the Cummins 6B (6BT, 6BTA) is the most popular diesel in the world. Note: mine has the fresh water cooled aftercooler so there's no maintenance required on it, unlike the salt water cooled aftercoolers.

 

[AUXOPdwp]

Love 6Bs

More Cummins 6Bs have been manufactured than any other diesel ever, in dozens of countries. When I shopped for my trawler, I purposely looked for 6BTs (no aftercooler, ie "6BTA"). Additionally, I wanted the older 210 to 250 hp 'MECHANICAL' version - no electronics. I couldn't be happier!


Yanmars need the timing belt changed every 5 years or 1000 hrs, if I recall. 6BTs have timing gears, no belt. Any marine diesel needs seasonal cooling system maintenance in addition to belts, impellers, filters and fluids regularly - learn to DIY. 6BTs need valves adjusted every 1000 hours and should have belt tensioners plus their brackets replaced at the same time. Google the Cummins 6B "Killer Dowel Pin" so you can prevent this rare but sometimes catastrophic problem in the course of normal maintenance.


Study Tony Athens' website (sbmar.com) intently, to avoid disappointment. Best of luck!

 

[charliemcvey]

I have a 1986 42 Jefferson twin Perkins T6-3544. 200 hp. Normally run 1500-1600 rpm. Have completed the loop twice. First time in 2016 we had a fuel burn of 3.3 gph average for The Whole year. That was both engines and generator total. second trip averaged 3.6 gph. Very economical.
Charlie McVey

 

[AUXOPdwp]

Perkins track record

Glad to hear you have enjoyed your Perkins as many have.
Unfortunately there aren't many Perkins dealers left in the USA. My neighbor threw a rod in one of his engines aboard his DeFever 49. Perkins couldn't send a replacement engine from England because the older design didn't meet EPA reg's. There were no used ones to be found in North America.
So, my neighbor had his engine crated and shipped to England for Perkins to rebuild. It cost him $60K in 2014 dollars to repair his boat. Cummins has ample re-man's available to avoid this sort of tragedy.
Just sayin.

 

[Comodave]

Glad to hear you have enjoyed your Perkins as many have.
Unfortunately there aren't many Perkins dealers left in the USA. My neighbor threw a rod in one of his engines aboard his DeFever 49. Perkins couldn't send a replacement engine from England because the older design didn't meet EPA reg's. There were no used ones to be found in North America.
So, my neighbor had his engine crated and shipped to England for Perkins to rebuild. It cost him $60K in 2014 dollars to repair his boat. Cummins has ample re-man's available to avoid this sort of tragedy.
Just sayin.

Before I spent that type of money on a Perkins, I would have bought 2 Cummins remans and sold the good Perkins.

 

[charliemcvey]

Transatlantic Diesels in Hays Va.
tadiesels.com
I Have purchased Perkins parts, they advertise overhaul kits and rebuilt Perkins and other engines.

 

[Boatingbill]

I actually have access to quite a bit of Perkins stuff. My brother-in-law has been a Perkins dealer for years, and knows pretty much every old time Perkins guy in the country. If anyone needs parts let me know what you need. I can check for you. The grey market stuff won’t be cheap, but can probably find it.