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Old 13-09-2013, 21:16   #16
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re: Detroit Diesel Question?

The only Detroit Diesel I ever fooled with was an old 318. Four things stick out in my mind.
She was loud.
She was snappy.
She was 2-stroke
She had a special kill valve for when she started up backwards & ran away off of her pan oil.

That last part is probably the most important to understand. A peculiar thing about that motor, is that she can run backwards if you let off the key at just the wrong moment when cranking her over. When that happens. she then sucks the lubricating oil out of her pan & fuels herself with this unregulated supply of oil. The motor then runs away at very high RPMs that are well over red line. Either you hit the emergency kill valve pretty quickly, or she will suck the pan dry & self destruct. After you have deployed the emergency kill valve, you then need to reset the gizmo before you can try to run the engine again. I seem to remember that involved crawling under the motor to reach a reset actuator that was in a very dirty & inconvenient spot.

I don't know if the motor you are looking at is equipped with this kind of emergency kill system or not.
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Old 13-09-2013, 22:11   #17
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re: Detroit Diesel Question?

My $0.02 worth.

If you want efficiency at trawler speeds, go with a long stroke diesel (under square).

If you want higher speeds from diesels, you have Yanmar, Cummings 5.9 for a small engine, better choice would be a 3208 Cat, larger engines the entire 855 cid inline 6 Cummins line, 3406 Cat, Mann. I'm just not a fan of 2 stroke Detroit Diesels even though I had an 8V92TA.
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Old 13-09-2013, 22:28   #18
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re: Detroit Diesel Question?

GG, I have worked on a couple of boats with the V series Detroits, and from limited experience, I think they will out last you If feed clean fuel, oil and coolant. The boat with V16-92s that I worked on was ear splitting, but insulation kept the guest cabins quite. The nicest motor yacht that I worked on had a pair of Gardner Diesels, that turned slow and sipped fuel. In my own opinion (only mine) I would look for a single screw boat with a bow thruster. Less cost, maintenance , fuel (also a little less speed) but an easier boat to maintain. I envy you being able to raise your kids on a boat, but going fast is not normally a criteria for a family boat. _____Just another opinion. ____Grant.
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Old 14-09-2013, 08:44   #19
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re: Detroit Diesel Question?

One of the reasons I buy the Eagle, sinlge engine, is because it had a DD 671. The DD 71 &72were and still are one of the most popular reliable engines in the world. Still plenty of parts service availible. However the size and hp depends on the applicatio. Deisel engines like to have load worked.

The DD 71 & 72 are know as the green leakers. However they do not leak to much. Sure you will a to have a diaper and wipe up occational but most e.gines in time will leak. As for noise you can quiet down with muffer wrap and mufflers and sound proofing the e.gine room. I like the sound of big engines.

Its not only the size of the engine but weather it natural or terbo. Natural are meant to foroer rpm and turbo for higher rpm. For slow speeds natural is prefered. Not much can go wrong with a 2 stroke its the stuff hanging of them and poor maitenance that shortens their live. I prefer 2 strokes over 4 strokes as the have very few moving parts.
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Old 14-09-2013, 09:15   #20
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re: Detroit Diesel Question?

Noise and maintenance would not be a problem for me as only millionaires could afford to run them ! A boat of that size will cost tens of thousands of dollars per year to run and maintain if you do any cruising at all . Smaller boat . smaller engines
Do you intend to cruise ? Have you got millions ?.
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Old 14-09-2013, 09:35   #21
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As someone else has already stated, the 71 series Detroits are rugged reliable workhorses. The technology in them was at least 20 years ahead of anything else on the market when they were first introduced. I have owned a 92 series in my converted bus for 10 years now. I would not be afraid of a 92 series in a boat but the 71s are dry sleeved and that takes away some of the potential failure points that the 92s are susceptible to.

The notion that any 2-stroke HAS to be a slobbering mess is just silly. They can be but so can any engine if you abuse it enough. The bigger issue with the 2-strokes is finding a mechanic who understands them. You can always find a wrench puller but a mechanic is another matter. I can count on the fingers of one hand the mechanics in all of North America who I would trust to work on my bus. The marine world may be better because there's still plenty of the old girls hammering away in fish boats.

As far as the sound goes - its what a diesel should sound like.
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Old 16-09-2013, 07:00   #22
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re: Detroit Diesel Question?

Here is a good basic article about diesel engines you may want to read to learn the differences between the types of engines and how they work.
Marine Engines - Comparing Diesel Types: Two Cycle, Four Cycle
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Old 16-09-2013, 09:00   #23
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re: Detroit Diesel Question?

As post before I would not be too concerned about the DD 71 or 72 as long as they been maintained and not to many hours on them. I for got to mention one of the advantages are they can be rebuilt in fame/in place as the cylinders can be re sleeved. Also in the engine is natural, non turbo, and sized correctly they can be very economical to run.

However I am astonished dismayed, shock surprised stunned that GG would be looking at motor yachts with DD 12V71T1C which are 12 cylinders and turbo charged gas guzzlers. For over a year now GG has insisted the boat be blue water/ocean capable, full displacement and fuel efficient.
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Old 17-09-2013, 18:03   #24
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re: Detroit Diesel Question?

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Originally Posted by rw58ph View Post
As post before I would not be too concerned about the DD 71 or 72 as long as they been maintained and not to many hours on them. I for got to mention one of the advantages are they can be rebuilt in fame/in place as the cylinders can be re sleeved. Also in the engine is natural, non turbo, and sized correctly they can be very economical to run.

However I am astonished dismayed, shock surprised stunned that GG would be looking at motor yachts with DD 12V71T1C which are 12 cylinders and turbo charged gas guzzlers. For over a year now GG has insisted the boat be blue water/ocean capable, full displacement and fuel efficient.
It's ok Phil, I'm still a bit shocked myself, but this may be a better way to go for me in the long run. I will hold the boat for 2-3 years, then sell it and buy something great, that I really want. Maybe even something smaller than originally thought, as my oldest son may be on his way to college and I won't need the same space as I do now. If I get something for less money now, than I can get something better later. Trying to find what I really want now, with enough accommodation is a very difficult if not an impossible task, as we all know Besides, the first year is all about learning to operate and short trips. Mostly living at the dock. The second year will hopefully have more cruising, and by the time I get to year 3 I'll be ready for my passagemaker...with a raised pilothouse
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Old 17-09-2013, 18:03   #25
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re: Detroit Diesel Question?

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Originally Posted by rourkeh View Post
Here is a good basic article about diesel engines you may want to read to learn the differences between the types of engines and how they work.
Marine Engines - Comparing Diesel Types: Two Cycle, Four Cycle
Thanks.
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Old 17-09-2013, 18:06   #26
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re: Detroit Diesel Question?

Funny thing about noise, I had the owner start the engines for me today at a second showing and they seemed much quieter than the Cat engine on the Dixon. I was very surprised by that.
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Old 17-09-2013, 18:14   #27
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re: Detroit Diesel Question?

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Originally Posted by GalaxyGirl View Post
Funny thing about noise, I had the owner start the engines for me today at a second showing and they seemed much quieter than the Cat engine on the Dixon. I was very surprised by that.
Diesels are louder when first fired up cold. I had a 1693 TA Cat that was quite loud from a cold start, louder than my 8V92 TA Detroit.
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Old 17-09-2013, 18:17   #28
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re: Detroit Diesel Question?

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Originally Posted by GalaxyGirl View Post
Funny thing about noise, I had the owner start the engines for me today at a second showing and they seemed much quieter than the Cat engine on the Dixon. I was very surprised by that.
For me, the Detroits sound nice at idle....It's when they're actually doing something that they drive me nuts. The sound of the blowers just gets into my skull. I worked on a supply boat that had a 53 series detroit for the hydraulics and it sounded like a hoover vacuum cleaner through the earmuffs.
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Old 17-09-2013, 18:19   #29
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re: Detroit Diesel Question?

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Originally Posted by Diesel_Doctor View Post
Long time lurker, First post

12v71 where some of the best iron Detroit Ever poured.
They are, however, a dry block with a sleeve, which requires a series of steps be followed when the engine is rebuilt, in order for the liners to not have hot spots. Surprisingly few people seem to want to go through all the steps, I guess feeling that they know more than the people who designed the engine.
A fairly unknown weak point is the spring pack and the splined shaft which drives the blowers and that usually only fails in applications with lots of throttle changes (think in a truck). However, I would still carry the parts in my spares collection. Otherwise, very very simple and very reliable. Fuel wise they are thirsty compared with anything which is 4 stroke and way less efficient than any of the modern (electronic) engines. But you don't need a laptop to work out what is wrong with them. Parts are mostly available although some things can be hard to find as they don't make new ones anymore and most of what is left is in boats.
92 series Detroit I would suggest staying away from - they where not the best thing Detroit ever built.
Slobber- detroits under light load or at idle tend to pump oil up past the piston rings and it comes out the ports in the lower portion of the liner and then the constant pressure inside the air box blows the oil out the air box drains. Many people rig something up to drain this oil back into the pan. I would not do that as there is too much junk in that oil to ever want it in the oil pan. Also, gaskets tend to leak and there are a number of bolts that tend to leak oil if the bolt is not installed properly. But, with work they can be made quite tight in terms of oil leaks.
Thanks Diesel Doctor for taking the time to register and chime in.
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Old 17-09-2013, 18:21   #30
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re: Detroit Diesel Question?

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For me, the Detroits sound nice at idle....It's when they're actually doing something that they drive me nuts. The sound of the blowers just gets into my skull. I worked on a supply boat that had a 53 series detroit for the hydraulics and it sounded like a hoover vacuum cleaner through the earmuffs.
ok, maybe that's why, because it was at idle. The engine room also seemed well insulated.
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