Detroit Diesels 8.2 litre FWC

[paulga]

I saw a boat with Twin Detroit Diesels 8.2 litre FWC, each with ~2k hours.
I didn't find a lot of clue from search, so posting my questions here.
I want to know the annual maintenance cost of this engine.
How to determine if they are due for an overhaul soon, and how much to expect for the rebuild cost, are parts still available?
Does it have aftercooler?

How does the twin engines compare with a single Cummins 4BT3.9 150hp with 3k hours?

 

[tiltrider1]

My opinion.

They were ok engines in their day. The were nothing special but they seemed to have lived a reasonably long life. They had some early issues that got correct and after that all seemed to be well.

However, I do not see much support for the engine now. Parts and mechanics are becoming scarce. I feel owning 8.2 now is a little like Russian Roulette. You just hope nothing goes wrong on your watch. Now what are the odds that they will blow up on you? I don’t know, we really don’t know the life of these early post WWII diesel engines.

I would first see if you can find a local business that supports the engine and ask them how they feel about the future of the engine services wise.

While tHe 8.2 is a Detroit Diesel it does not have the same after market support that the older 2 cycles have.

 

[Comodave]

Take the Cummins…

 

[Arc]

Fwiw , had a buddy with a pair in a black fin. They got tired about 3,000 hrs and were replaced

 

[Rufus]

Well, I have 17 years of experience operating them in our OA 440. That said the 250 HP (no intercooler) engines only have 1560 hours on them. I run them little harder than you'd run a Lehman, hull speed plus in the semi-planing OA hull...8-9 knots @ 1500 rpm...enough to be on boost. If the seas are moderately bumpy, I'll run a little harder to get the hull on semi- "plane"....12-13 knots... 2200-2300 rpm. Other than oil changes, I've replaced belts, impellors, antifreeze, and oil religiously (synthetic). I also removed and cleaned out the heat exchangers. So far, zero issues. Zilch.

The intercooled 300 HP version did not do well in go fast planing boats. BTW, the 250 HP version of the 8.2 makes 150 HP at about 1800 rpm. (I think they'd live OK at that power).

 

[paulga]

Fwiw , had a buddy with a pair in a black fin. They got tired about 3,000 hrs and were replaced

what were they replaced with, how much was the cost?
should a twin engine be replaced with only twin engines? the cost maybe lower if replaced with a single engine?

 

[paulga]

Take the Cummins…

the Cummins already has 3k hours. parts may be readily available, the cost is still high in case of a rebuild. Is it expected with a longer service range than the Detroit?

 

[BruceK]

what were they replaced with, how much was the cost?
should a twin engine be replaced with only twin engines? the cost maybe lower if replaced with a single engine?

Replacing engines is a major project, think exhaust systems, gearboxes, engine bearers, shaft alterations,electrics...as well as just finding the engines. Then there`s getting the old ones out, new ones in, which can necessitate dismantling parts of the boat and or engines, plus stuff I`ve not thought of.
Better to find the boat you want fitted with what you want, with some flexibility thrown in.
Switching from twins to a single will have its own challenges, like closing off 2 shaft thru hulls, creating a new one, keel issues, rudder issues, on top of what`s mentioned above.

 

[paulga]

Replacing engines is a major project, think exhaust systems, gearboxes, engine bearers, shaft alterations,electrics...as well as just finding the engines. Then there`s getting the old ones out, new ones in, which can necessitate dismantling parts of the boat and or engines, plus stuff I`ve not thought of.
Better to find the boat you want fitted with what you want, with some flexibility thrown in.
Switching from twins to a single will have its own challenges, like closing off 2 shaft thru hulls, creating a new one, keel issues, rudder issues, on top of what`s mentioned above.

No wonder engine replacement can go above the boat value. The alternative is rebuilding. If parts are not available, it's not ideal.

 

[tiltrider1]

There are a few engines that would not have bothered me 20 years ago. DD 8.2, Cummins 555, and Volvo Tam series. Today those engines on average are 30+ years old and parts are getting scarce. I personally would pass on any boat with those engines.

Now there are other equally as old engines, Cat 3208, DD 2 cycle, Lehman. These engines still have good support and parts are easy to source.

This is just my opinion.

 

[Comodave]

the Cummins already has 3k hours. parts may be readily available, the cost is still high in case of a rebuild. Is it expected with a longer service range than the Detroit?

Ask OC Diver, he put one in his boat about 6 or 7K hours ago. Parts,are available and support is good/great.

 

[Comodave]

what were they replaced with, how much was the cost?
should a twin engine be replaced with only twin engines? the cost maybe lower if replaced with a single engine?

Probably not practical to replace a twin with a single. It is possible but likely not cost effective.

 

[Crux]

Its time well spent to gather all info avaiable.....

https://everythingaboutboats.org/detroit-diesel-8-2/

 

[Crux]

To give Cummins equal time.....lots of info on developement of the B series...and why it ended up in Dodge pickups...after being turned down by GM and Ford Lol!!
https://www.ebay.com/p/783087

And if you want to back to the beginning.....

https://www.amazon.com/Diesel-Odyss...2d-a1b4-c4e17f140a1d&pd_rd_i=0615590152&psc=1

 

[Lepke]

Rebuild parts are not a problem. From DD or after market. Parts like exhaust manifolds, etc., sometimes show up on ebay. There may be after market heat exchangers.
Few of the 8.2 engines were made compared to the 2 cycles so there isn't the depth of service or parts.

 

[ranger58sb]

I saw a boat with Twin Detroit Diesels 8.2 litre FWC, each with ~2k hours.
I didn't find a lot of clue from search, so posting my questions here.
I want to know the annual maintenance cost of this engine.
How to determine if they are due for an overhaul soon, and how much to expect for the rebuild cost, are parts still available?
Does it have aftercooler?

How does the twin engines compare with a single Cummins 4BT3.9 150hp with 3k hours?

There are several threads here on DD 8.2Ts. Lots of controversy, ranging from decent/OK to "it'll blow up in two minutes." Use the Google search tool...

We had one, in our '87 Mainship 34 III. Ours were 210 HP, IIRC. (Or maybe 220?) Not aftercooled, IIRC. Ours had the recall fix (larger head bolts, etc.) and worked fine. Seemed well suited for that application, which was essentially low "trawler speed" cruising. Maintenance costs were minimal: fluid and filter change, raw water attention, done.

A comparison of twin 8.2s vs. a single 4BT would depend on boat and application. (Really, a 4BT? Not a 6BT?)

-Chris

 

[sunchaser]

Its time well spent to gather all info avaiable.....

https://everythingaboutboats.org/detroit-diesel-8-2/

Very informative article on the 8.2s. Nice to see facts vs opinions. Thanks

 

[paulga]

There are several threads here on DD 8.2Ts. Lots of controversy, ranging from decent/OK to "it'll blow up in two minutes." Use the Google search tool...

We had one, in our '87 Mainship 34 III. Ours were 210 HP, IIRC. (Or maybe 220?) Not aftercooled, IIRC. Ours had the recall fix (larger head bolts, etc.) and worked fine. Seemed well suited for that application, which was essentially low "trawler speed" cruising. Maintenance costs were minimal: fluid and filter change, raw water attention, done.

A comparison of twin 8.2s vs. a single 4BT would depend on boat and application. (Really, a 4BT? Not a 6BT?)

-Chris

yes, 4BT3.9, so 4 cylinders? what is B and 3.9?

 

[rslifkin]

yes, 4BT3.9, so 4 cylinders? what is B and 3.9?

The engine model in that case means 4 cylinder, B series engine, Turbocharged. A 4 cylinder Cummins B series is 3.9 liters in displacement, so some people add the 3.9 for clarity.

 

[Pete Meisinger]

Total rebuilds are expensive, doesn't matter the make. Generally a rebuild will cost about half to a third of installing a new engine, with a lot less hassle.

As diesels become more sophisticated they become less compatible with older boats. Sure, you can make anything work but will the additional cost be worth it? Some things to consider when replacing a 35 year old engine with a new one are: none of the gauges will be "plug and play", torque and hp curves will be different meaning new props and transmissions, probably you will need new shafts too, Fuel delivery and fuel return will need to be considered. Stringers and mounts may not be compatible.

Finally, an old boat with new engines is still an old boat. The new engines are certainly a selling point but really don't add much to value.

pete

 

[Rufus]

Very informative article on the 8.2s. Nice to see facts vs opinions. Thanks

That article is chocka block full of "opinion", observation versus hard engineering facts, and inference based on speculation. There are no data to back up the number of failures in service, nor the numbers of failures due to a given design "issue". It uses illustrations of blown head gaskets from an engine that is not an 8.2....pictures of bent rods from a non-8.2... It's the worst excuse for a supposed engineering "technical" paper I've ever read, and I've read a lot of them. A compilation of BS dock talk. Pathetic.

 

[sunchaser]

Rufus
Having been the proud owner of two of the 8.2s - the second one was a warranty replacement for the first- the facts are the engine was a total failure for me. The pathetic article you refer to was scribed by a pretty smart diesel guy.

 

[Rufus]

Rufus
Having been the proud owner of two of the 8.2s - the second one was a warranty replacement for the first- the facts are the engine was a total failure for me. The pathetic article you refer to was scribed by a pretty smart diesel guy.

...more opinion and dock talk. I have two and they're absolute gems.

The article gathers up examples of failures, depicts photos of engine parts that are not 8.2 (leaving the impression that they are), and provides zero statistics regarding how many failures were due to a supposed design issue, how the engines where operated, what type of boat, how they were maintained... infers that shared rod bearing surfaces caused untold failures (every V configured engine in Detroit's 2-stroke line uses this arrangement). It's not an engineering report, it's an opinion report. Show me the data as to how many specific failures were due to poor maintenance and abusive operation, and I might give it some credibility. It's a sloppy hit job. I've written many engineering reports....this is not one. It's dock talk posing as a technical report.

 

[sunchaser]

...more opinion and dock talk. I have two and they're absolute gems.

You're to be commended for keeping your engines in tip top shape.

My 8.2 failures were not dock talk, truck talk. GM was kind enough to take the truck back.

I've friends who replaced 2 with 6BTs and another who replaced two with Deere 6068s. Not dock talk, they wanted to cruise for 1000s of trouble free miles every summer which before the changeover was of concern with their less than tip top diesel abilities.

Again, thumbs up for your skills.

 

[Action]

Its time well spent to gather all info avaiable.....

https://everythingaboutboats.org/detroit-diesel-8-2/

After reading this, I would never want a boat with an 8.2l engine.

 

[Rufus]

You're to be commended for keeping your engines in tip top shape.

My 8.2 failures were not dock talk, truck talk. GM was kind enough to take the truck back.

I've friends who replaced 2 with 6BTs and another who replaced two with Deere 6068s. Not dock talk, they wanted to cruise for 1000s of trouble free miles every summer which before the changeover was of concern with their less than tip top diesel abilities.

Again, thumbs up for your skills.

Cute. I don't have great "diesel skills", but I do have a brain and maintain and operate these engines where they survive just fine. In usage, I think of them as 120-130 HP Lehmans with a big cushion. I tell every prospective buyer exactly that. (By the way, thanks for sabotaging prospects for selling the boat...rather mean spirited, I'd say)

Which version (NA, early turbo, later turbo) and year of the engine in your truck? What size truck? Why did the first one fail? What was wrong with the second one? We've been in this debate before with no specifics from you. Just opinion...same as the undocumented opinion paper in the link.

 

[2savage]

My Seaton 50 has a single DD 8.2 that is the original engine for the boat so it is 54 years old.

It was rebuilt and now has 2K hours. The only issues were a rebuild of the transmission heat exchanger and a bad battery caable.

The rebuild was done before I became the owner and the bill was about $16,500 so maybe $20k in todays money.

 

[SeaDogAK]

My Seaton 50 has a single DD 8.2 that is the original engine for the boat so it is 54 years old.

It was rebuilt and now has 2K hours. The only issues were a rebuild of the transmission heat exchanger and a bad battery caable.

The rebuild was done before I became the owner and the bill was about $16,500 so maybe $20k in todays money.

The 8.2 was introduced in 1980, so there aren’t any that are 54 years old.

 

[Sailor of Fortune]

I had 2 8.2's in the late 80's early 90's.... My mechanic told me to think about repowering the boat... He said GM no longer supported them.. I wouldn't buy any boat with them... I don't care who has had a good experience with them..

 

[Comodave]

I had 2 8.2's in the late 80's early 90's.... My mechanic told me to think about repowering the boat... He said GM no longer supported them.. I wouldn't buy any boat with them... I don't care who has had a good experience with them..

Agree but I might be forced to buy them before Volvos…