DD 8v71s and 8v92s info

[JohnEasley]

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

[racclarkson@gmail.com]

John,

Detroits ain't noisy. They are loud alright, but what a sound! 2000 hour rebuilds if they're turbos and run hard. Less than 2000 if they aren't maintained. Lots more hours if run at hull speed and lots and lots if they're naturals. They can smoke, but I've seen every brand smoke--lots of variables. With attention to detail, the leaks can be almost completely eliminated--my ER is clean. 71's are considered to be a bit more bullet-proof than 92's. Plenty of others will jump in I'm certain.

[JohnEasley]

Detroits ain't noisy. They are loud alright, but what a sound!

Robert,

We've been looking at the 53 EDMY. Other than docking or anchoring, we're planning to spend the majority of time underway at the lower helm station. My wife is going to rule out a Hatteras if 8v71s are loud enough at hull speed that we have to raise our voices to carry on a conversation in the pilothouse. We'll end up looking for a different brand of boat.

[racclarkson@gmail.com]

Robert,

We've been looking at the 53 EDMY. Other than docking or anchoring, we're planning to spend the majority of time underway at the lower helm station. My wife is going to rule out a Hatteras if 8v71s are loud enough at hull speed that we have to raise our voices to carry on a conversation in the pilothouse. We'll end up looking for a different brand of boat.

Well I guess that's why call'em admirals.

[bobk]

We run our 48' MY with 6V92's at 1000-1100 RPM. Noise isn't bad inside but we never run from below. On the bridge it is quiet.

We have >4000 hours on them SMOH and there is no smoke, they start easily and we burn 5.5-6 gph at 8 knots. Mine are the small 425 HP versions. The stories about shorter lives in the 92's is really related to the sports fish where the owners push them hard.

Good luck in your search. These Hatteras yachts are great boats and this forum is a good place for all sorts of information and advice about them.

Bobk

[GJH]

On my 56MY (8v92tti) we carried on conversation at normal voice levels at hull speed and didn't have to raise our voices much if going all out.
There are more dockside myths about these engines than about anything else in boating. Rather than once again beat this horse to death, Search the archives here and boatdiesel.com... pages and pages of experience already related. If not cared for, yes, they can smoke (especially if way over-propped) and leak if ignored, but they shouldn't.

[SEVEN]

Robert,

We've been looking at the 53 EDMY. Other than docking or anchoring, we're planning to spend the majority of time underway at the lower helm station. My wife is going to rule out a Hatteras if 8v71s are loud enough at hull speed that we have to raise our voices to carry on a conversation in the pilothouse. We'll end up looking for a different brand of boat.

All boats underway are noisy, drive from the fly bridge and take in the sights and fresh air. Most DD have minor leaks but that’s part of the general maintenance. Mine do not smoke even at start up. I don’t run her at WOT but do blow her out just before I berth. I have 1800 hours and have friends with 4,000 hours and they are still strong. It all depends on how you treat them. I agree with Robert Oh what a sound. Great motors.

[Boatsb]

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

[MadHatter53]

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

[racclarkson@gmail.com]

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

We sons of the South will affirm.