DD 8v71s and 8v92s info

[SKYCHENEY]

Almost every 53MY I see has 871's. There is one 1986 that has 692's that I know of.

Half way through 1985 they switched to 6v92s. So, mid 85 through 88 they all had 6v92s

[Shoreline1a]

Afternoon all,

Being doing a little research on the specs, history, and reputation of these engines. The general impression I'm getting is that they are noisy, tend to smoke, leak oil regularly, and need to be rebuilt about every 2000 hours. On the positive side, parts availability and prices are decent. As a two-stroke engine, they don't get nearly the fuel consumption rate at hull speeds compared to four stroke engines like the Cummins.

Please school me on the good and bad of the 8v71s and 8v92s.

Thanks.

John

John, I had 8v71n's in my '71 45' Convertible. You understand the issues. Mine leaked oil like a sieve and the mechanical noise from the injectors was very loud. Normal conversation in the salon wasn't possible. The salon being right over the engines didnt help. On the plus side, the engines didn't smoke after startup, got good fuel economy at displacement speeds and parts availability was good . In terms of rugged reliability, aspirated 2-cycle Detroits are the the equal of any modern diesel. I love the exhaust note.

I have since repowered with Cummins 6bts 210 hp. I run the boat at displacement speeds so i didn't need big iron. The duty cycle for the boat is to take us from Bellingham to Alaska in the spring, fish all summer and return in September. The boat is perfect for this application, with new power and genset, 2 freezers and plenty of redundant systems. A Hatteras really turns heads in the remote areas of Alaska.

[SEVEN]

I'm a new Yorker from birth so I can carry on a conversation over my Detroit's with no mufflers at wot.

Know that is funny. Hay New York.

[Walter P]

I have 6-92's in my 1982 Series I 48' MY and they are very quiet.....unless you go down into the
engine room. Years ago shortly after I bought the boat, I replaced all the sound proofing in the ER with
Soundown and it really made a big difference. My boat has two very large mufflers on each engine as
well and all we hear on the flying bridge is a low steady hum. I doubt that Hatteras' are any louder
than any thing else and in fact they are probably easier on the ears.

Walt

[JohnEasley]

I have 6-92's in my 1982 Series I 48' MY and they are very quiet.....unless you go down into the
engine room. Years ago shortly after I bought the boat, I replaced all the sound proofing in the ER with
Soundown and it really made a big difference. My boat has two very large mufflers on each engine as
well and all we hear on the flying bridge is a low steady hum. I doubt that Hatteras' are any louder
than any thing else and in fact they are probably easier on the ears.

Walt

Hey Walt,

What is Sundown? Do you have a link? I Googled it but couldn't readily find it.

Thanks.

John

[JohnEasley]

I appreciate all of the replies. Late yesterday, I spoke with a broker who has a 61' MY with 892s for sale. He said it has 3600 hours on the engines, no leaks, and no smoke other than the normal diesel start up. He invited me to come over and start the engines myself. He also echoed many of the things you guys said. Thanks again.

[Pascal]

Noise levels vary with each boat and there are two types of noise. Exhaust and inside mechanical

The exhaust of some boats are quieter than others For instance the 58 MY with 8V92s is much louder on the FB than the 53 or 58 YF with 71s. It s a nice sound but gets a bit tiring after a while

At the lower helm most boats are quiet especially at hull speed. If any mechanical noise makes it thru it's usually because of bad seals on the ER doors or around the engine hatches. It can also come thru some of the wire chases from ER to helm and saloon. All which can be easily addressed

[bobk]

I appreciate all of the replies. Late yesterday, I spoke with a broker who has a 61' MY with 892s for sale. He said it has 3600 hours on the engines, no leaks, and no smoke other than the normal diesel start up. He invited me to come over and start the engines myself. He also echoed many of the things you guys said. Thanks again.

Look up some old posts by Genesis on a start-up test which I think he called a 30 second compression test. It will give you a quick assessment of engine condition. It does require a cold start.

Bobk

[Nightingale]

We had 892 TI's in the 56 Hatteras MY and it was extremely quiet in the main salon and lower helm. I have run 2 56 Hatts differing in years (1981 and 1984) easily 10,000+ miles combined. In the 56 even the exhaust note is pretty quiet confined to a low rumble.

Inside the engine room is another story with a mechanical note that I grew to absolutely love.

[Bob Bradley]

I'm a new Yorker from birth so I can carry on a conversation over my Detroit's with no mufflers at wot.

Ahhhhh! Now that explains everything.