Diesel engine hours-gctid351670

[Jim_Gandee]

Fleet, when looking at 89-94 38XX's what would you say are good engine times? Proper and timely maintenance notwithstanding what is considered high, mid and low time? Would one prefer to see a certain number of hrs/year to prevent internal corrosion? Is there such a thing as not enough time? Thank, Jim

[kwb]

At that age - hours start to not matter so much v. general upkeep.

I could go down put boat in water program the pilot to go do laps around vashon island at idle and other than fuel probably do nothing to the engine in terms of longevity but the hour meters would show tons of hours.

I could also go put boat in water firewall the throttles and run to AK and put very few hours on the meters but have taken away engine life.

Since almost all boats (brokers) will say they were run by the proverbial granny back and forth to church on sunday you have to do other bits of investigation. How clean is the bilge - too clean can be a bad sign as well, how are the rest of the sytems conditions? Does it look like upkeep has been an ongoing effort over life of boat (replaced items are of varied ages) or have things been done at one time and not much since?

I will admit I once left key on in an old boat for a week - that added about 150hrs that really weren't there. Low to me would be less than 1000, high over 3500.

[Guest]

Jim Gandee wrote:
Fleet, when looking at 89-94 38XX's what would you say are good engine times? Proper and timely maintenance notwithstanding what is considered high, mid and low time? Would one prefer to see a certain number of hrs/year to prevent internal corrosion? Is there such a thing as not enough time? Thank, Jim

Jim, there are MANY variables to factor into the equation. It depends on which type of engine, how it was used, and the conditions under which it was used. I know this doesn't help much, but it is a reality. Many people falsely believe Diesel engines last forever. That impression is largely due to the reputation low performance Diesels have held. Many motoryachts do not have low performance engines. Many are equipped with turbochargers (which takes away from the life of the engine) and many have been run at high RPM's for long periods.

For instance... When I was considering repowering my boat with a high performance or mid performance Diesel engine, I was impressed by the torque and horsepower numbers given their weight and size. However, I quickly learned these engines cannot be treated like gas engines; otherwise, they will end up having the short lifespan of a gas engine. I then looked into low performance Diesel engines and it opened up a whole new world for me. I saw properly maintained Perkins 4.108 engines with 8000+ hours on them and still running strong. So those are some factors to consider. A 2000 hour high performance Diesel might be close to the end of its life.

Get it checked by a Diesel mechanic who has extensive experience in the particular engine in question. That will give you a better idea of what to expect than any of us putting out a number.

[smitty477]

"Fleet, when looking at 89-94 38XX's what would you say are good engine times?"

Jim ,

Which engines are you asking about? What is the displacement, and are they turboed?

The non turboed Hino EH700's with their larger displacement can run 'forever' if properly maintained and loaded.

Others vary dependent upon what you are looking at.

KWB puts it well - "At that age - hours start to not matter so much v. general upkeep."

Perhaps one thing to keep in mind is that you are purchasing the previous owner as much as you are purchasing a boat.

Hope this helps

[kwb]

smitty477 wrote:
Which engines are you asking about? What is the displacement, and are they turboed?

The non turboed Hino EH700's with their larger displacement can run 'forever' if properly maintained and loaded.

The naturally aspirated aspect is what kept the 38 in scope as I was looking. Hino turbos are very expensive compared to many others and as they get to be longer in the tooth I don't see prices dropping.

The Manicooler is the other "risk" item on these and there are ways if you stay on top of things to keep those going indefinitely I think they are a good choice in an engine that you can stand a chance of making live a very long time without a lot of upkeep costs or very expensive repairs.

The 210's were good for the 38 as there is more room in the bilge but for the tiny amount of useable HP and faster cruise over the 175 I ruled them out because of the turbos and associated costs of keeping them working.

One year in I have had to do the following:

Change oil & Filters

Change Raw Water Impeller

Had Both Manicoolers Ceramic coated after finding some pitting in one of them

Painted Manicoolers (didn't want the ceramic look)

Dipped the Cooling Bundles to clean while the Manicoolers were being coated

Changed Coolant

As you can see from the list - most of that is annual stuff you will do to anything. The other stuff was deferred work from the PO and what I would call normal for at least once in a 20+yr old boat lifetime. The absense of the added complexity of a Turbo or coolers associated with it will help keep upkeep simple and hopefully affordable. There is probably a valve adjustment due and maybe an injector service but I have no symptoms of either being very important to get done compared to some of the other non-mechanical items I have to do this off-season.

[SomeSailor]

I just bought a trawler with a pair of 120 Lehmans (less than 3000 hours each) and when did some checking around was told that naturally aspirated, light loaded (twins) that they could easily see 20,000 hours if maintained and operated properly. They're not super high compression motors and at 1750 RPM they just chug along forever.

[Guest]

Somewhere in the 90's I think the 38s engines were changed from the 175 Hinos (someone else can be more specific). I have 1988 38 with NA 175s. I have owned the boat since 1994. To date I have spent $ on maintenance, I have used a professional Earl Summerville since I am not knowledgeable about engines. I consider that a good investment and am glad to pay for his services. The Hinos have had the manicoolers removed, cleaned, inspection plates regasketed, bundles cleaned, valves adjusted, timing adjusted. The boat has lived all of its life in fresh water, a big factor. Earl said when he was done with the manicoolers "that if kept here and run as I do I might not have to do much to them, they looked like they were 3 years old." Currently there are shy of 1500 hours and run like new. I do not run them with throttles to the firewall but do run them at cruising speeds of 15 knots periodically with much running at trawler speeds - 6 knots. Oil and filters are at timely and frequent times. Cooling fluids also. I have heard that these engines could live 15,000 hours(?), if such is the case I cannot live long enough to wear them out. Other systems receive the same maintenance.

Having said all that what others have mentioned is very true, you are buying the previous history of the boat and how it was run and maintained.

Hope this helps and good luck in your search.

Richard in Wisconsin

[tonyiiiafl]

Richard Tulip wrote:
Somewhere in the 90's I think the 38s engines were changed from the 175 Hinos (someone else can be more specific). I have 1988 38 with NA 175s. I have owned the boat since 1994. To date I have spent $ on maintenance, I have used a professional Earl Summerville since I am not knowledgeable about engines. I consider that a good investment and am glad to pay for his services. The Hinos have had the manicoolers removed, cleaned, inspection plates regasketed, bundles cleaned, valves adjusted, timing adjusted. The boat has lived all of its life in fresh water, a big factor. Earl said when he was done with the manicoolers "that if kept here and run as I do I might not have to do much to them, they looked like they were 3 years old." Currently there are shy of 1500 hours and run like new. I do not run them with throttles to the firewall but do run them at cruising speeds of 15 knots periodically with much running at trawler speeds - 6 knots. Oil and filters are at timely and frequent times. Cooling fluids also. I have heard that these engines could live 15,000 hours(?), if such is the case I cannot live long enough to wear them out. Other systems receive the same maintenance.

Having said all that what others have mentioned is very true, you are buying the previous history of the boat and how it was run and maintained.

Hope this helps and good luck in your search.

Richard in Wisconsin

I know it is not uncommon for a 6-71 Detriot Diesel (My favorite type!) to clock 30,000+ hours before any overhaul!

[kwb]

tonyiiiafl wrote:
I know it is not uncommon for a 6-71 Detriot Diesel (My favorite type!) to clock 30,000+ hours before any overhaul!

Yea but they will have leaked almost as much oil as fuel they burned.:arr

The old 2-stroke detroit is a stupid simple design from the 30's (1936?) but even those suffered a poor fate when they started pulling lots of HP out of them.

[tonyiiiafl]

kwb wrote:
Yea but they will have leaked almost as much oil as fuel they burned.:arr

The old 2-stroke detroit is a stupid simple design from the 30's (1936?) but even those suffered a poor fate when they started pulling lots of HP out of them.

yes, some were leakers for sure, but there were the good ones too. They originally had 246 HP (highway) and 300 (marine). The design stayed teh SAME until 1982. A simple 2 stroke with a blower. Then, in 1982, they just hung a turbo on it and increased the HP to 315 (highway) and 400 (marine). This could vary with the injector size. Unlike the Cats and Cummins, the top rpm on a Detroit stayed teh same at 2100. Cats in marine service (3208) were spinning faster. They smoked a bit, but fired right up, no injector pump to deal with and again, simple to work on. I owned many of these engines, 6-71, 6V92TA(Silver series) and 8V92TA Silver series). They all served me well and never let me down. I had 2 leakers, the 6V92 and 8V92 when the retainer clips inside broke and oil was leaking into the air boxes and right out the breathers. After a rebuild (On Detroit Diesel after 350,000 miles) they were fine as can be.

[dmcb]

And they run forever. There is nothing like the sound of Detroits in a boat.

I know of a 56' Chris Craft Roamer bought new about 1965. The original owners son now owns the boat and its still going strong.

The only serious mechanical thing I know of was in the 60's. The same son still in school, changed the oil in the genny. For some reason he way overfilled it. It took oil from the crankcase and ran away seiously damaging the engine.

As the shut down was fuel, it didn't work because it was getting its fuel from the crankcase.

The older emergency shut down on Detroits to prevent runaways was air shut down.

I had one in a semi I owned and liked it.

Doug

[Guest]

In post #7 I stated about the manicoolers that if I kept the boat here and ran them like I have in the past I wouldn't have to do much to them. I want to clarify that so nobody is misled. I did not mean to say that they wouldn't need much attention but rather they would likely do well with a less rigorous program of disassembly. Inspecting the cooling bundles periodically would still be necessary to verify they were not being plugged by scale, debris, impeller parts, etc. Other maintenance issues still apply.

Richard

[Woodsong]

DD's will last a looong time but I sure don't want them in a boat of mine! Too darn noisy for my tastes- I like the peace and quiet of a quieter engine and the DD's are thirsty things which is $$$ in today's economy. That is why the old sportfishing boats and motoryachts with DD's are selling so cheap these days- no one wants to deal with the fuel bill.

Hours are misleading though for sure. A continuously run diesel will go for 10's of thousands of hours. The shutting down, turn on, sitting idle for long times, not running with a load on them, etc. is what kills them.

[Guest]

kwb wrote:
Yea but they will have leaked almost as much oil as fuel they burned.:arr

The old 2-stroke detroit is a stupid simple design from the 30's (1936?) but even those suffered a poor fate when they started pulling lots of HP out of them.

I agree these Detroits could have done better if there were design changes. However, the leaky oil is an issue you can properly mitigate. The Perkins 4.108 I'm going to be using in my repower is notorious for developing oil leaks in the rear main seal after 1500 hours. However, there is an aftermarket seal available that performs better. But that's not the issue. These engines were designed to last because very critical operations depended on them. There are countless Detroit 4-71's in life boats; and the only reason they are not used today is because the engine is discontinued. When there is a critical function and a reliable Diesel engine is needed, the ones with a proven track record such as the Detroit X-71 series or the Perkins 4.108 tend to be good choices.

Going back to the original poster's question. We can see from the responses there is no magic number with regard to the hours. You absolutely need to know the condition of the engine and how it has been used in the past. It is very common to see low numbers on Diesel engine hour meters but see the engine having been run into the ground. If there is a turbo charger, it kicks in after a certain RPM. If the previous owner did not run the engine fast enough to need the turbo charger, the engine likely has more life. A good mechanic would remove the turbocharger and inspect it. From looking at the blades and the clutch assembly, it is possible to tell how much use it has gotten. Heavy use of the turbo charger results in minor cavitations in the blades; and they can easily be identified by a qualified mechanic.

Testing the engine's oil will also give you some good insight. You will be able to see the condition of the valves. It will also be able to determine whether there is a presence of coolant in it -- which is an important factor in determining the overall condition of the engine and how much life it has left in it. The fuel dilution in the oil is also another factor. If the injectors or injection pump have compromised seals, the oil test will reveal it.

These will be bargaining points, should you decide to make an offer on the boat!!!

[kwb]

One time sample of oil is almost meaningless - you have to have a series of samples to really get good read on what is going on.

Detroit 2 stroke were discontinued for two reason - they burned more fuel than other of similar HP, they couldn't pass emissions standards.