92 series DD's

[saltshaker]

It all boils down to how high the HP and how hard they are pushed. A 435HP 8V71TI is very reliable but when you add a bypass blower and push it to 535HP they rarely make it past 1500 hours. 265HP 671Ns will run forever if cared for but a 485HP 671TIB that needs a rebuild before 2K hours is common. Same holds true for the 92 series although some of the higher output engines are actually better than the lower output versions. I'd take a 550HP 6V92TA over most other 6V92's.

 

[Cricket]

There's very few 92's without turbos, if any, in these boats so that's one difference, pretty sure the non turbo 92's will hold up just as well as a non turbo 71's. The turbo 92's issues started when DD started pushing the horsepower up further than it probably should have been. I'm not sure DD really ever tried to make the HP leap with the 71's (except 6-71) that they did with the 92's. The 6-71 turbo at 410hp was much more reliable than at 485hp. Also I think the quality of the parts went to hell at some point which is why I gave up on them and installed Cats.

 

[captddis]

But back to the original question if I understood it correctly, 71's vs 92's. I was under the impression that 71's took less of a beating due to the smaller cylinder capacity and less HP, therefore less "wear" for lack of a better term, and therefore less of a chance of tearing them up and having to rebuild. Any truth to that? Or just a matter of personal preference. Or maybe it's more a matter of how they are operated and maintained?

Cheryl
Cinderella
1971 53 MY

It is not the engine, it is about the load. imagine a little four cylinder compact car. It is fine driving around town for groceries. Take the same car and hook a camper to it and it will die from overloading.
Same with a boat.

 

[oscarvan]

From the Hatteras owners manual. I quote
" CAUTION"

" TO PREVENT EXCESSIVE EXHAUST BACK PRESSURE AND ENGINE OVER HEATING AT EXTENDED IDLE, THE EXHAUST RAW WATER BY PASS VALVE SHOULD BE NO LESS THAN 3 1/4 TURNS OPEN "

Ah.....

So ALL Hatts have a raw water bypass valve? Is this the same as the side discharge discussed earlier?

Is it because without enough exhaust flow the water isn't pushed out hard enough and can start filling the exhaust?

 

[SKYCHENEY]

Thank you, thank you, thank you, Captddis. Finally, someone telling the truth about these engines from personal experience and not just repeating dock talk from someone with no first hand experience. All the bad rap on the 92 series comes from those who don't really know what they're talking about. Again, thank you.

 

[Boatsb]

Thank you, thank you, thank you, Captddis. Finally, someone telling the truth about these engines from personal experience and not just repeating dock talk from someone with no first hand experience. All the bad rap on the 92 series comes from those who don't really know what they're talking about. Again, thank you.

But some guy told me different and he knows better because he remembers what a guy told him when he was visiting a guy who knew about it too.

Where did forest go?

 

[GJH]

Ah.....

So ALL Hatts have a raw water bypass valve? Is this the same as the side discharge discussed earlier?

Is it because without enough exhaust flow the water isn't pushed out hard enough and can start filling the exhaust?

No, they did not. In fact most did not, he is just quoting the manual from a boat out fitted with the set up.

My thanks as well to Dave for the great replies. As Scott satirically points out, these engines are subject to more hearsay "dockside legend" than any other.

 

[34Hatt]

You all have to be careful here If you start listening to Dave who really does know what he speaks a true expert, the Sky is going to fall.

 

[jim rosenthal]

My previous boat, a 44' Striker, had 6-71s (naturals) and had the exhaust water bypass as well. I didn't realize the manuals called for it, though.

There was a post here a few years back saying that the most accurate measure of engine stress and wear was the number of gallons of fuel that had gone through it. Essentially, the more power you ask of an engine, the faster it will wear out it's replaceable parts such as bearings, rings, seals, etc. It makes sense to me.

I had a Mercedes 240D years ago. I bought it with 80K miles on it, drove it a quarter of a million miles, and gave it to one of my godchildren who drove it another 30-40K and sold it to buy a newer Mercedes diesel. I think it made about 65 hp. Low-stress engine hauling a fairly light car around. Similar cars have gone half a million miles before an engine major. If you don't ask too much of it, a diesel engine can run a very long time.

 

[captddis]

You all have to be careful here If you start listening to Dave who really does know what he speaks a true expert, the Sky is going to fall.

Thanks Dan. But I have a niche' with the older boats. I still can't program my phone!

 

[captddis]

My previous boat, a 44' Striker, had 6-71s (naturals) and had the exhaust water bypass as well. I didn't realize the manuals called for it, though.

There was a post here a few years back saying that the most accurate measure of engine stress and wear was the number of gallons of fuel that had gone through it. Essentially, the more power you ask of an engine, the faster it will wear out it's replaceable parts such as bearings, rings, seals, etc. It makes sense to me.

I had a Mercedes 240D years ago. I bought it with 80K miles on it, drove it a quarter of a million miles, and gave it to one of my godchildren who drove it another 30-40K and sold it to buy a newer Mercedes diesel. I think it made about 65 hp. Low-stress engine hauling a fairly light car around. Similar cars have gone half a million miles before an engine major. If you don't ask too much of it, a diesel engine can run a very long time.

The manual I quoted was for my 46CHP. It was something Hatteras did not DD.

 

[bobk]

Thanks Dan. But I have a niche' with the older boats. I still can't program my phone!

Dave, you must be one of them young fellers who have a phone that needs programing. Mine just flips and works

Bobk

 

[saltshaker]

You all have to be careful here If you start listening to Dave who really does know what he speaks a true expert, the Sky is going to fall.

Why is Sky falling? Did he slip on the snow up there?

 

[captddis]

Dave, you must be one of them young fellers who have a phone that needs programing. Mine just flips and works

Bobk

I got my first cell phone in 1988. It was a Radio Shack three watt and I paid 1250.00, thought I got a deal as my friend had paid 1495.00 for his! My Motorola lazer was the best. I could get on a flying bridge and get reception in the middle of the Gulf. Between the batteries and expensive analog service, it was getting me.
The final straw was a delivery from Detroit to Miami, I recieved a 600.00 roaming bill when I got home

 

[SKYCHENEY]

Why is Sky falling? Did he slip on the snow up there?

No more snow. Gonna be in the 50s next week.

 

[34Hatt]

Why is Sky falling? Did he slip on the snow up there?

Not our Sky here the one above us all

But I am sure you knew that, beside even Buffalo NY doesn't have snow yet nobody is slipping yet

 

[Boatsb]

No more snow. Gonna be in the 50s next week.

They say it may get into the 50's in the next few weeks. So far lows been in the 60's.