DDEC Reliability

[whoover]

I'm looking at a boat with DDEC enginge controls. How reliable are the ECU's now that they are getting older. The boat is a 1998 with 16V92's. How many members here are running the electronic controlled engines and how is your experience. Is the DDEC basically a fuel, timing and monitoring system.

Thanks
Walt Hoover

 

[rsmith]

I see guys on the Detroit forums on FB constantly looking for displays and ecm parts worst of both worlds 16 wet liner cylinders and a half azz electronic conversion. There is a reason big DDEC boats are cheap.

 

[jim rosenthal]

Didn't DDECs have a bad rep even when they were new?

 

[rsmith]

There were at least 2 65C’s that went to full throttle when docking. I saw the one that tboned the Viking at the big game club in Bimini. Say what you want but the Hatt faired a lot better than the Viking. The sides of the hull tore like tissue paper.

 

[cww]

Not reliable at all. The displays and ECU's are temperamental and cost a fortune to replace if you can even find them at all. Detroit is usually good about providing factory support on all their stuff, DDEC is the big exception to that rule. There is no tech or parts support, you're on you're own, and all of it is proprietary. I wouldn't buy a DDEC boat.

 

[Pascal]

And the descendent, MTU-DD is no better. I was quoted $22k for a new screen…. The ones in the ER which have about 20 buttons to control the engines and gears, costs over $50k!

 

[Captain Ralph]

There are two ways to think of a large 92; Your rich.
The second part of a DDEC system is; Your famous and still very rich.

On a budget; you don't want this combo.

Rich and famous???; There are shops that will will repair these dinosaur controls and displays.

You will require spares and a good tech who can work on them correctly.
Not just part swap but diagnose correctly and not insert new issues.

So lost brother, from another mother,, Are you rich and famous ??

Now you may understand;

There is a reason big DDEC boats are cheap.

 

[whoover]

I'm not rich, just comfortable, not famous either. There is another possibility that has 12v92's that are not DEDEC. Thoughts on this package.

Walt Hoover

 

[rsmith]

I know people will disagree but these wet liner engines either leak coolant or will leak soon. If it’s never been rebuilt you have old brittle seals and if it has new parts and the quality of the mechanics are not what they used to be. Everything from rubber bands to tires rubber parts are just crap today. Local Detroit independent guy quit working on Detroits because the quality of the parts. He told me he’s seeing 5-7 years on the liner seals.

 

[Fanfare]

My 8V-71NA engines seemed ready for a rebuild in 1993. For some reason involving height above/below deck mine could not be turbocharged so no extra horsepower there. I wrote Jack Hargrave a letter asking his recommendation on whether to rebuild or replace. He said I should go with the DD 6V-92TA, at 550 hp adding 200 hp per side. Nothing bigger would fit. So I did. In the approximately 30 years since then I have had even fewer problems with the new engines than I did with the old, which is saying something. They haven't been rebuilt, don't leak anything, and with water cooled exhaust manifolds reduced engine room temperatures a lot. DD wanted me to order DDEC version 1 which would give me 35 more hp and a nifty digital readout but I finally decided on the old mechanical models because I knew more about how to fix them. Major considerations also were the lightning strikes in the Bahamas possibly frying the engine electronics and also the unproven history of the new systems. DDEC was really about reducing emissions and after three revisions was abandoned. Meanwhile mine have been great. After several tachometer replacements I have lost track of engine hours but at about 100 hrs per year should be around 3,000, rarely run above 2850 cruise. I do worry about the O-ring seals and contemplate a preventive rebuild but for now if it ain't broke...

 

[firbanks]

Question - does the DDEC reputation also apply to the control systems on Detroit Series 60s? I've heard very good things about those engines otherwise.

 

[Captain Ralph]

I'm not rich, just comfortable, not famous either. There is another possibility that has 12v92's that are not DEDEC. Thoughts on this package.

Walt Hoover

Years ago, there was an area shop that specialized in removing DDEC injectors & equipment from the ole 2-strokes, then installing new mechanical injectors, electronic controls and N2K gauge panels.
Usually after a lightning strike (on a clear day), it did offer a more reliable platform.
This was still an expensive job.

Next,
I do luv my 71s. Very forgiving and near bomb proof.
I'm not a big fan of Detroits wet liners (92 & 53s) and do not consider them forgiving.
But the 92s do (did) offer lots of performance.
The Rub; (IMO) Performance engines require lots of maintenance including more frequent rebuilds.

Next,
MTU has been having serious quality issues on their made in China liner kits for a while now.
I have not been to impressed with the non-factory kits either.
Then, those freaking seals.

Next,
Your next engine tech. Working on ole 2-strokes requires an experienced tech with a flexible and strong back.
HA, their extinct..

Find all the history you can about those engines. Find people who have watched the owner/captain operate her (gently or abusive?).
Find the most knit picky & through DDC surveyor you can.

Good luck on your shopping.
Who knows, all this typing may be for not, You may have found a jewel.

One last thought;
New gen-set or same old dinosaur OhNo?
This could be a sign; Patched up or repair/replaced correctly.
I would feel a lil better about the engines if there was a newer gen-set down there correctly installed.
Anything else down there that may look like poor or great service may also help on engine service attitude.

 

[Captain Ralph]

Question - does the DDEC reputation also apply to the control systems on Detroit Series 60s? I've heard very good things about those engines otherwise.

DDEC is a multi level system. Penski built the DDEC for his 2-strokes as a learning step.
It really was not researched, developed and implemented completely. Not much intelligence in these first ECMs but it did keep some smoke down (better than the old throttle delays).
Error codes still come out of these devices that there is no explanation for.

From the ground up the Series 60 was built as an electronic engine. Electronic components were built up with the engine. ECMs, injectors, throttle control are in another worlds from the original DDEC.
On some installs, there may be that same $%^ LCD display. But that is where the similarity of DDEC stuff ends.

I think the Series 60 is still one of the most amazing engine ever made.
There were some original marinizing problems that took a while to fix but now they are bomb proof

 

[cww]

Question - does the DDEC reputation also apply to the control systems on Detroit Series 60s? I've heard very good things about those engines otherwise.

By the mid 2000's when most marine Series 60's were being installed Detroit had figured out how to make reliable electronics. The issue wasn't the concept of DDEC it was the implementation. Detroit basically decided to learn at the public's expense. The first 2 or 3 versions of DDEC were basically overcomplicated crap and instantly developed a bad reputation. Over the years that followed they worked the bugs out. Changing emissions requirements led to the phaseout of 2-stroke engines and the learning curve wasn't quick enough that the 2-strokes benefitted much from it before they were discontinued. I think there are 3 versions of DDEC that came on 2-strokes, and none of them were all that great. But they did keep learning. The Series 60's after the first year or two of production are bulletproof. I have several friends with those and they love them.

 

[whoover]

Thanks Ralph for the insight, the engine space is very clean and squared away. The generators are still the original Onans. All of the records from the owner before this one are on the boat including receipts for the rebuilds that were done about 800 hours ago. The wet liner o-rings are not new to me, my 903 had them. Coolant maintenance is critical and never let anything get hot. What's strange is that for the checkered reputation of the DDEC engine there isn't alot of internet information on failures. There are alot of these engines out in the world in many applications from marine to power generation. I'm not trying to talk myself into anything, I like to have all the facts.

Thanks
Walt Hoover

 

[rsmith]

My neighbor just sold his beloved 65 donzi with the 16/92 ddecs. The boat was mint and the engines were perfect and it went so cheap you wouldn’t believe it. I was really tempted but had a,reality check.

 

[Captain Ralph]

We have an acquaintance that has a big Donzi that had those big 92s.
He survived a rebuild and were running fine, he just wanted to sleep better.
He re-powered with Cats.
Real happy camper now and sleeps very well (No Worries).

 

[Pascal]

There is big Delta here on the next tee head, 125’ or so from the late 90s. It had big DDs… failed after rebuilt by DD. He threw in the towel and Repowered with 3412s. No more problems.

In the 1200-1600hp range you just can’t beat the 3412Es and the C30/32s. Well except for the after coolers on the later cats

 

[Captain Ralph]

There is big Delta here on the next tee head, 125’ or so from the late 90s. It had big DDs… failed after rebuilt by DD. He threw in the towel and Repowered with 3412s. No more problems.

In the 1200-1600hp range you just can’t beat the 3412Es and the C30/32s. Well except for the after coolers on the later cats

Yep, the 34s are truly bomb proof.

 

[northshoreone]

Just curious, does anyone have an idea on how much the 3412 reman cost?