Hatteras 48 CPMY and 52 CPMY - seeking suggestions & info

My only slight concern would be the 8V92TA. Older 2 stroke technology and pretty high HP rating for the displacement. Thorough engine survey a must

I am a Detroit guy. However, I never suggest strung out 92s.
Not a lot of them around but the 3408 is just a little better than the 92s.
Something else, try to stay away from the strung out 3208s.

My only slight concern would be the 8V92TA. Older 2 stroke technology and pretty high HP rating for the displacement. Thorough engine survey a must

Keep in mind, any 1990’s era Detroit 92 series (6v, 8v, 12 or 16v) will be some version of DDEC (Detroit Diesel Electronic Controlled). Whereas engine parts like pistons, heads and bearings are readily available, parts and service for the DDEC portion is getting very difficult to source.

Remember that first V-8 Chevy you got when you were young? 2 barrel carb, maybe 140 HP, ran great and if you cared (cheap fuel) good MPG.
Then came the 4bl carb, advanced timing. And more.
You were surprised when it turned to mush running down the road on that last down-shift.
It died strung out beyond the factory specs.

Now take the temperamental Series 92. That is 92 cubic inches per cylinder that makes power every time the piston comes up (2 stroke). Great work horse from the factory. Started life less than 50HP per lung.
Ran great, lasted forever.
Roger Penske (DDA owner at that time) took the 92 series, added electronic controls and increased that to around 100HP per lung.
Johnson-Towers, Covington, Pan-Tropic, Stewart-Stevenson and many others took the 92s way past 100HP per lung.

So, hopefully you see where I'm going with this;
High performance reduces engine life. Extract high performance from a PIA engine (92s) reduces engine life.
Extracting high performance from a 92 is a gamble that lots of boaters take.
Most boaters have learned to go slow and puke un-burned fuel from the exhaust and still complain about MPG.

There is lots more to learn about Detroits, in a nut shell, If you must get an DDC older boat, stay with the 71s if you can. If you must get a 92 engine, try to get one tuned around 75 to 85/90 per lung.
At 90+ HP per lung, they are strung out. Any engine life is a gamble, low speed is not doing much better as un-burned fuel is going out the exhaust and washing oil from the piston rings.

Bottom line, any boat, any engine must get a real engine survey. This done correctly, may take longer than the boat survey. If the engine surveyor looks like he is enjoying the ride, fire him and get a real tech.
Rebuilding these engines start at $3k per lung and goes up quickly from there. That is not including R&R of the engine or heavy parts.

Now, for your entertainment, at no additional cost; stand by as I get blasted by the residents in the peanut gallerys.

Look at the HP per Cylinder ratio.

6V92s start at 250Hp and Penske stopped these at 625HP. Others took it further.
The 625HP, 6V92TIAB-DDEC has a factory life of; It might start a second time.
Anything beyond that is a gamble. However, there is a great YF member with these engines. His have started more than three times.
I'm sure he babys them well.

The 34 series is a great Cat engine line. Still supported well. Just you usually find the 3406 or 3412s. The 34 V8 was just not installed in a lot of boats.
For long life, I would go for the 3406.

The 32 series is an old line. Some later blocks for the higher HP tunes have an updated oil passage design.
These blocks are getting harder to find. To little help, to late.
Over 450HP, when they fail, nothing is re-usable.

It's all relative to comparing to other engines. I had 12v92s in my boat that were there for 25 years. They were fine for 3000 hours. That being said, I had two major failures in 3 years and lost a whole season each time. I also had difficulty getting service and parts. So I decided to take them out go with something comparitevly more reliable. I spent a boat load of money (pardon the pun) and repowered with CAT C18. The 92 series DD's are generally known to go about a max of 3k-4k hours between major overhauls. The CAT C18s, well above 10k hours. Of course some will go more, some less and there is never a guarantee.

There is also the efficiency factor. Typically a 2 stroke engine like the Detriots will burn more fuel than a 4 stroke like a CAT, MTU, MAN or Cummins

Way more than what you are buying the boat for and way more than the boat would be worth after repowering it. I wouldn't go into a purchase thinking to repower.

8V92 @ 750,,,, 93.5 HP per cylinder. Just about becoming an engine I have been trying to explain for you to avoid.
IMO, this is a high performance & high maintenance engine that may go 3000 hours. You may get lots more, maybe less. You will never get great MPG.

Question;
Is that 1760 hours since rebuild or life?
Who marinized it? Detroit, Covington, Johnson-Towers or an other company?
What large service history does the engine have?

Just to give you another thought, DDCs last 8V92TA was a DDEC (electronic controlled) and maxed at 760 SAE HP.
Their last 8V92TA non DDEC engine made 734 SAE HP.

From post #8;
Rebuilding these engines start at $3k per lung and goes up quickly from there. That is not including R&R of the engine or heavy parts.

$24K to start plus yard and heavy work.