71's vs 92's

[rwappleton]

Good Morning All,
Ramping up the search for a 53MY. I have been through the project boat with a 43DC and I now want one that just needs the usual stuff.

I have lot's of experience with the 71 series in boats ,trucks and M-113A1's. I have run into several boats with the 92 series and would like to know the good,bad and ugly from people that have operational experience with them.

My concerns are why I almost never see one with more than 2000 hours. We are going to cruise full time and an overhaul every 4-5 years does not appeal to me or my wallet.

Lets hear it!!!!!

Thanks,

Russ

[SKYCHENEY]

Depends on the HP rating and use. You can't get a 92 hot; it will melt the orings around the liners and dump the coolant. When we were in the ready-mixed concrete business, we owned many 71's and 92's. They were all good motors. You just had to be a little more careful with the 92's. The early ones were problematic and almost sunk DD, but the "silver series" corrected that.

My 6v92's in the boat have 4500hrs on them and they still fire up immediately with little to no smoke that clears in 30 seconds.

If I were buying today, I would not be afraid of a 92 at any number of hours as long as the engine surveyed well. Just do the maintenance and don't let them get hot.

[jim rosenthal]

Engine condition is more important than engine model, all other things equal, but 71s are probably less risky.

Some of this depends on which 53MY you want. If you prefer the older classic model, you may be limited to 71s just as a function of boat age.

A few 53 MYs were built with engines from Cummins, and possibly even from Cat, although that last I have only heard about, never seen. And some 53s have now been repowered with more modern diesels.

[SKYCHENEY]

Engine condition is more important than engine model, all other things equal, but 71s are probably less risky.

Some of this depends on which 53MY you want. If you prefer the older classic model, you may be limited to 71s just as a function of boat age.

A few 53 MYs were built with engines from Cummins, and possibly even from Cat, although that last I have only heard about, never seen. And some 53s have now been repowered with more modern diesels.

Why are 71's less risky? A 92 is much easier to overhaul. The wet liners make it so just about anyone could do it. The 71 cylinders have to be honed just right so the liners make full contact. A bad job could create hot spots on the liner. Also, the marine 92's are mostly the aftercooled setup where the 71's are intercooled. The more I type here, the more I'm convincing myself that I'd rather have the 92's.

In reality, the least risky is buy a naturally aspirated one. Much fewer potential failure points that way.

[doc g]

then you have to worry about exhaust riser and manifold issues without the turbos ........Pat

[Walter P]

The early 92's had some issues but they were addressed and fixed. That's why in the "expert opinion" of
many somehow the 92's are inferior engines. They are not..... I have had boats with various 71's as well
as 92's and they all served me well. Any engine regardless of brand or model will expire early if they are
not maintained properly. I believe most failures are in some way due to poor maintenance.

The bad rap on the 92's remind me of the well known eulogy to Julius Ceasar by Marc Antony.. "The
good that men do is interred with their bones, the bad lives after them". The same seems to apply to
the 92 series engines. I certainly don't claim to be an engine expert but my own experience has been
very good with the 92's.

Walt

[jim rosenthal]

Walt, you DO win the "reference of the day" award. That has to be the most erudite quote we've seen around here in a while.

Mind you, this may be because your moderator has been reading a biography of Buddy Rich..... great drumming but not much erudition.

[northshoreone]

I have had both the 12v92 and currently have 16v92s. I had a liner failure on one of the 12v92s at about 2k hours..but most of those hours were put on by a previous owner. No way of knowing if it had been overheated by him at some point. The current 16v92s have over 4k hours and start right up with a short burst of smoke which clears in about 30 sec. which I'm told by very experienced Detroit Diesel techs is just what they do! No need for concern. Once up and running ...a very light haze of smoke in the distance at 1900 rpm. With burning over 100 gal. per hour I guess not surprising.. I am having valves adjusted this spring and we will see if that helps at all. The rebuilds ...as mentioned here..are very easily done in frame and compared to other engine mfg rebuild costs ...very reasonable! Proper care and keeping the heat down is key!
I know a gentleman here in FL that started his engineering career years ago with GM being assigned to the 16v92s He told me that they were great engines and that if run and cared for properly, they would last 10k hours! We all know in a marine application that may not be the case but the total life of an engine is based on total fuel burned, proper care and keeping heat in check!

[Westfield 11]

Walt, you DO win the "reference of the day" award. That has to be the most erudite quote we've seen around here in a while.

Mind you, this may be because your moderator has been reading a biography of Buddy Rich..... great drumming but not much erudition.

Wasn’t Buddy Rich known as one of the most unpleasant men in Jazz? I seem to recall contemporaneous accounts of working with him that eluded to “difficulties”.

[madhatter1]

What years were "early and problematic" Anyone have a basic year to year account of what to look for, avoid, and check for upgraded parts to resolve issues? That would be good info as a sticky on the top of tech Talk. I bought in even though I had some concerns because I knew Dave would have addressed any issues that that Esperanza would need being 1982 engines but I still have no idea if there were any issues in 1982.

Many, many, many of old Hatt's (and Bertrams) have plenty of life left in them but no one knows anything about DD's anymore.