Detroit two stroke

Wow 2DASEA,
What hp are they rated for.
How much do they weigh?
What I'm most interested in is what configuration is the crankshaft? Do the pistons rise and fall together or alternately? I suspect together.
This engine is only one cu in less that my Mitsu. I wonder how suitable it would be for Willy (my boat). I'm guessing it probably weighs about 500lbs. I'm also wondering if it is as smooth as my four stroke 4 cyl.

I spent a lot of time working a couple of 353's

2DASEA said:

Here's my little 2-53!

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in the early 60's I ran a John Deer backhoe that was powered by a 353 and later a Pettibone fork lift. Worked the crap out them with almost no maintenance.
Always started easily,always finished the day.

The 2-53 crank throws are 180 degrees apart. 2 power strokes per revolution just like your 4 cylinder 4 stroke.

Bill

Cessna wrote:

"2 power strokes per revolution just like your 4 cylinder 4 stroke."

I've never heard of a 0 degree crank 2 stroke twin and for obvious reasons. It would be just like a single cylinder engine w two cylinders. There would be reduced piston speed and cooling advantages may result but the advantages of smoothness is great. When I asked ......."What I'm most interested in is what configuration is the crankshaft? Do the pistons rise and fall together or alternately? I suspect together." .....I was thinking of 4 stroke stuff. Sorry.

It always amazes me to think of a 6-71 as halving as many power strokes as a 12 cylinder engine. And the one and two cyl 2 stroke outboards are MUCH smoother than the 4 stroke engines.

OK I first must apologize by bring this old thread back to life.

I am looking at a late 80s trawler/cruiser. 53' 15.8' beam. It has twin DD 6V92T with 1400hrs.

I have figured out by reading this thread and other research that these engines are:

V-6 configuration 2-stroke
Sleeved cylinders
92 CID (per cylinder?)
Has a Turbo.

So I have read here these engines are bullet prove, noisy and easy to work on.

Tell me more of the good, bad and ugly please.

Pay 25 bucks and join Boatdiesel.com for a plethora of real info on these engines.

How many horsepower? How have the PO's run it? These engines are the classic example of "don't exceed 1 hp per cubic inch of displacement" maxim. You have 552 cubes to work with there. Examples of these engines that have been juiced up and run at the pins are where a lot of the mythology comes from.

There is more folklore and old wive's tales about DD engines than almost anything else in boating.

I have a pair of 8v92TI's, FYI. Love 'em.

The listing shows them as total 480hp.

So George,

Are they fairly easy to work on for general maintenance?

When compared to other diesels they are really noisy?

Any issues I should look for?
What experiences have you had?

I will also join Boat diesel. Looks like an interesting site. Thanks

480 is a nice number, if you can find out how they have been run that's a bonus (via logs, not the broker's say-so).

On my boat, they are very easy to work on, each resides in its own engine room with stand up head room and plenty of walking around space where maintenance items a re located. The service manuals are still available from DD, I got mine 5 years ago and it had been updated this century, forget the exact year.

Yes they are very noisy when you are next to them inside the boat. Having run boats with Cats and Lehmans and Cummins, the DD is definitely louder at similar RPM. But with the right exhaust set up they sure sound beautiful outside, many love the sound of Detroits more than any other engine, even those that don't otherwise care for them. On my boat, they are not very noisy at all up in the pilot house and quite quiet up on the bridge. In the PH you can converse at normal voice volumes. But having run boats with Cats and Lehmans and Cummins, the DD is definitely louder at similar RPM.

It is essential that you find, through references, a mechanic who knows them to survey these very thoroughly prior to purchase. To do it right can take two days.

Be religious about following the maintenance routine, not so much more so than other diesels, but especially the cooling system, including the intercoolers. You can run them all day at very low speed, but take about 15 minutes at the end of the day and run them within 10% of WOT. Like most systems on a boat, you love them and they'll love you back.

Another very good online source of information about these engines is the Hatteras Owner's Forum, even if it is not a Hatt, visitors are welcome! I will warn you that per my first post, there is a lot of very inaccurate hearsay and folklore about these engines on the internet (shock!). A good, articulate mechanic is invaluable, I have been lucky to find two out here on the east coast and there are a few others.

The GM 2 strokes are easy to work on require a few special tools & parts are cheap compared to other brands. They aren't very efficient, you may be able to go to a smaller injector to help in this area, one contractor I worked for had me change out the n70 injectors on a 12v71 to n65, this was when diesel had taken a big jump in price. This also helped out on how hot the engine ran, less fuel = less heat for the cooling system to dissipate. The 2 strokes uses twice the air as a 4 stroke so good filters are very important. Good luck

caltexflanc said:

I have a pair of 8v92TI's, FYI. Love 'em.

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I had a pair, also, in my 54' sport fisher. 8V92-760hp each. What a sweet sound those engines made. I had a big walk in ER that I carpeted with red carpet. Right between the 2 DDECS. I use to eat my lunch down there between those 2 monsters and loved every minute of it.

These engines will gobble fuel (compared to newer designs) IF you attempt to slow cruise at 6K.

Use them with positive pressure on the turbo for best results.


*******

"It would be just like a single cylinder engine w two cylinders. "

Steyer Damler Puch had a 2 stroke motorcycle with what was called a "Split single".

The two pistons used a single crank throw , with a master rod and slave rod to articulate the pair.

They would reach TDC together but due to the configuration of the connecting rods the EXHAUST would open first , and amazingly CLOSE first.

This was a good fuel saving idea as the intake could be tuned for positive pressure , without blowing fuel out the exhaust as on most gas 2 strokes.

These engines will gobble fuel (compared to newer designs) IF you attempt to slow cruise at 6K.

Click to expand...

Like I said a lot of wive's tales about these engines. Sorry to report FF that my engines failed to get that memo, ditto those in other Hatteras and Bertrams I know. Neither did either of the old school Detroit mechanics I use. Part of the positive mythology about how long they last is based on their use at very low trolling speeds by commercial boats. You have to take care of them as noted in my longer post.

FF,
If I remember that Puch 250cc motorcycle the second cylinder was basically a reciprocating supercharger. So only the "master" cylinder turned the crank. The Puch was a one of a kind I think. Never heard of another. Those Puch engineers were really thinking out of the box.

The Puch was a "V" configuration. I was talking only about an inline or parallel twin like a typical Yamaha or Suzuki 2 stroke twin. You'll never find a 180 degree crank (pistons rise and fall together) 2 stroke twin.

The Puch was a "V" configuration.

Sorry the split single looked like any other single cylinder engine , only by taking it apart could one find the two cylinders were installed one behind the other .

"Puch is perhaps best remembered in the US for importing the SGS 250, the first and last split-single seen there. Marketed by Sears in their catalogue as the "Twingle",[3] it was styled much like a BMW of the 1950s and 60s. The layout had been popular in Europe between the wars because it improved scavenging, and hence fuel consumption, a feature considered less important in the US. New models after World War II had an internal re-arrangement which improved piston lubrication, reducing wear on the most vulnerable part of the engine, while an early system of pumping the two-stroke oil, along with the twin spark-plug ignition, greatly improved day-to-day reliability. Despite the racing heritage and performance potential of the split-single engine, this particular Puch model, with a top speed around 110 km/h (68 mph), was at a disadvantage against the loop-scavenged two-strokes that arrived in the late 1960s. A total of 38,584 of the SGS motorcycles were produced between 1953 and 1970.[4]"

FF your recollection is far better than mine on the Puch. I was quite sure the two cylinders were fore and aft and not transverse. Just looked at all the wonderful links. Thanks Fred.
I rode a 250cc Zundap 2 stroke single extensively in the San Diego area when I was in the Navy in the early 60s. I'd actually like to have that bike back to putz around the country roads here in Washington. Interesting in that the Zundap had 16hp too.

FF I don't know why you say "Sorry"? Are you implying I just lost an argument? I didn't even know I was in one.

Here's what the roads are like all around this area. Would be great for a 250cc bike ride.

From DD to motorcycles? Thread hijac

From 2 stroke configurations to different 2 stroke configurations.

He's right FF. The thread tittle said DETROIT 2 strokes.

I'm all for thread rushing all the way out onto the plains of North Dakota but a lot of guys just want to stay in Marysville.

When I was very up tight about it (some time ago) most seemed to think it was business as usual or/and ... just fine.

Now I've been criticized 2 or 3 times this week for TC. Maybe there's just more vigilantes. Everybody wants to be a Sargent.

Or a Admiral;-)