Detroit Diesel

[Chief Engineer]

Has anyone seen one lately?

In my years, I have only seen one in a sailboat.

71 series

[jenny2]

Originally Posted by Chief Engineer

Has anyone seen one lately?

In my years, I have only seen one in a sailboat.

71 series

my friend a boat builder this was his last boat he built corbin desighn with a 6-71 main and a 2-71 gen set this boat will cruise 10 knots at 1600 its massive

[capt_douglas]

I see them on a regular basis, from the C-series, to the big 12 and 16 cylinder monsters on motorboats, but not on a yacht.

[Stillraining]

Iv got one...not in a boat however...great engines...tough as nails dependable...but NIOISY...but hey...some people like that..

Must have been a big boat...one could probably swing a 30" prop no problum.

[Blue Stocking]

I am sitting here in my living room looking at a WW2, LCT with ORIGINAL Grey Marine 6-71s. Noisy bast*rds, but the sound of security.

[David M]

Yes, they are still used on older workboats. There are still lots of 2-71 gensets out there. The mains on commercial boats are being replaced because they do not meet pollution standards being two-strokes.

I like the sound of the old 6-71's...brings back memories of being in Seascouts.

[Stillraining]

Hey Blue:

For some of us this sound just blows our skirts up..


Maybe I should hang onto it..just incase I ever do get that 80' sail boat...LOL...

YouTube - 6-71 Detroit Diesel at idle

[Blue Stocking]

Originally Posted by Stillraining

Hey Blue:

For some of us this sound just blows our skirts up..


Maybe I should hang onto it..just incase I ever do get that 80' sail boat...LOL...

Do you remember Brave Moppie. Dick Bertram and Bob Sherbert winning the Miami-nassau with 6-71s in a deep-V

[um saudade]

In the eighties I built a 63-foot staysail schooner. Used a four valve 6-71 for main power. Pushed it nearly to hull speed with power to spare. It also ran the refrigeration for two cold holds plus all the hydraulics, etc.

While they are a two-stroke don’t compare a two-stroke diesel to a two-stroke gas. The blower on a Jimmy completely exhausts the combustion chamber on each stroke. They accelerate rapidly and while they don’t have the longevity of the older Cats or Cummings they would go for 10,000 hours or so.

The big issue was the fuel economy and it stinks! They tend to suck fuel when pulling a load. I remember a couple of fireboats at Long Beach in the 90’s that had 12V-92’s for propulsion and main pumps, so ran three total. Would hate to buy the fuel!

Ran some 12V’s on gensets on a job once but they used much more fuel than the Cat D277's.

Other than fuel, they start easily and run very smoothly if the rack is set correctly. There is no injector pump on a Detroit but each individual injector must be timed.

Yes, at 1800(full governed rpm) you can hear the blower. Sound as if they are ready to self-destruct because they are firing every rev.

One advantage to the two stroke series is that they can run either clockwise or counter-clockwise with different starters and change the oil pump gears around. That made it easy to have opposite port and starboard prop rotation.

The old days,

Um saudade

[Mark Zarley]

Ah yes , the detroit diesel, trucking co loved them for the fuel savings. Drivers didn't because of the narrow power range (lots of shifting) and then there was the noise, nickname "the screamin gm-ee".

[lorenzo b]

I LOVE my 8/71, pushes my 70 ton steel shrimp boat along at 7 knts and sounds just like a Greyhound bus. Gets about a mile a gallon. Can't burn enough of that diesel.

[jenny2]

Originally Posted by Blue Stocking

Do you remember Brave Moppie. Dick Bertram and Bob Sherbert winning the Miami-nassau with 6-71s in a deep-V

gota love um 6-71- 610 most people say whats A 610 -1671-1692S-12-149 IVE WORKED ON BOATS WITH ALL OF THEM TUGS FISHING BOATS GM WON WW11 what more can i say detroit rules

[impi]

I have plenty of them in my yard - mostly stripped out of my old earthmovers - I still have Terex 24 motor scrapers powerd by 12V71's

[Capt Phil]

Drove a 65 foot power boat from San Diego to Cabo, PV and Mazatlan and return on several trips that had twin 8V-71's. Reasonably good fuel economy, a little noisy and they must be run up over 1600 rpm every day or so for at least 45 minutes or the turbos begin to plug. Cleaning the blowers is expensive and messy. You'll know when you have stuffed them by the black smoke coming out the exhaust covering the transom! Well cared for they should last many 1000's of hours. On larger installations it helps to have a smaller day tank to draw fuel from as they have a fairly high fuel return rate to keep the injector system cool. Good engines IMHO... Capt Phil

[drcot3]

I`ve got 2 x D/D 265hp 6/71N engines in my boat Hatteras DC43 1978 they do 2 mpg at 1200 rpm giving 8 Knots open the thortles and throw your wallet in the sea as they burn a lot of diesel, when fresh antifouling I get 20 knots on flat water then 15 knts top speed at 2500 rpm after 2 or 3 months, slight fouling.
by bullet proof engines but they are dirty with oil mist out of breathers I put pop bottles under the breather pipes to catch the oil mist. my engines are still clear at the wet exhaust tunnel when running.