What are High Engine Hours??

[Don L]

What do people feel are high engine hours on a 1985 350HP marine diesel?

People with 1980s engine feel free to give the HP, hours and how your engine is holding up?

BTW - I did a general google search and got answers from 5,000 to 15,000 hours. Of course the thing is hours tell nothing about how the engine was operated, just how long it was.

[rslifkin]

Even at a similar power output, lifespan can vary significantly between different engine models. And as you said, usage patterns have an effect. The wear on a 2000 hour engine will be very different if it's been run 200 rpm short of WOT for most of those hours vs if it's been run more gently. In my opinion, if it's got a few thousand hours on it, that's no big deal for most engines, provided it starts well cold, runs well, etc. Generally, the more hours there are, the more I'd want to do a thorough engine survey to assess the real condition of the engine(s).

[Comodave]

Which engine in particular?

[mvweebles]

Since you're looking at trawler/motoryacht style boats (vs sportfisher), I'd start to raise an eyebrow a bit somewhere in the 6000-7000 hour range. Sure, can expect north of 10k hours but would definitely start thinking about a price that reflects higher hours. In my opinion, Yanmars are often a bit lighter and run at higher RPMs so threshold would be a bit lower. Do not see many yanmars in the boats you're looking at though.

As Rlifkin insinuates, there are variables. Many engines have a wide range of ratings. Older Detroits could be de-tuned to 250hp, or blown-out to well over 600hp or more on the same block for sportfisher. At the higher ratings, 3000 hrs was often the max.

Peter

[Don L]

Originally Posted by Comodave

Which engine in particular?

don't know, are there ones to be concerned about?

[Max Simmons]

My un-scientific rule of thumb is I get wary if there are over 4,000 hours. Not necessarily a deal breaker, but I'd be doing a deep dive into the mechanincal survey and mentally factoring in a re-build down the road. My supporting documents for this? Nothing!

[psneeld]

Might as well as use a crystal ball with no engine model or what application it was used in and how it was used.

Any or all can go 5000-15000 with the proper application and care.

I had a brand new one eat a turbo at 3 hrs...and a bunch of other boat engines lose hose clamps...etc... after just a couple dozen hours and fry themselves.

Sometime age with low hours is just as bad.

yep...need a crystal ball.

[sunchaser]

Assuming a good build to begin with some lifespan factors are:

- Proper servicing of heat exchangers and after coolers
- Zero overheats
- Not over propped and able to hit design RPM with no incidents
- Clean, neat and soot free ER
- Fluids and filters routinely changed
- All engine hang ons, belts and hoses in A-1 shape

There are many more.

[Don L]

I see how this is going to go. So never mind and sorry to waste people's time. No need to respond with maybes, possibilities etc. it was a general question for a general answer.

[O C Diver]

Originally Posted by Don L

don't know, are there ones to be concerned about?

As an example, a Cummins 6B (natural 135 HP) could still be good with 20K hours.

A 6BT (turbo 210 HP) could be still good at 10K hours.

A 6BTA (turbo, after cooled 370 HP) might not last 5K hours.

Ted

[psneeld]

General question gets general answers...like "it depends"......

Even Ted's response above gives multiple answers and that's only for one basic engine.

[Fletcher500]

Originally Posted by Don L

I see how this is going to go. So never mind and sorry to waste people's time. No need to respond with maybes, possibilities etc. it was a general question for a general answer.

Your posts always end on a sour note when people are trying to answer your questions.

Here is your answer: 4,978.

[mvweebles]

Originally Posted by Fletcher500

Your posts always end on a sour note when people are trying to answer your questions.



Here is your answer: 4,978.

Yep....

[Don L]

yeah I realize it is my fault

[BruceK]

If only.

[tiltrider1]

In the 80’s we thought anything over 2500 was high hours. In the 90’s we thought anything over 3500 was high time. After 2000 we thought anything over 4000 was high time. In 2010 we thought anything over 5,000.

Now we think high time is over 6,000.

Honestly, everyone here believes most diesels will easily make it to 10,000 if taken care of.

Some of us have experience with diesels that have made it past 20,000 hours in other applications.

So the best answer is “depends”.

[Portage_Bay]

Originally Posted by Fletcher500

Your posts always end on a sour note when people are trying to answer your questions.



Here is your answer: 4,978.

4,978? I'm at 4106. Guess I'm running on borrowed time!

[hmason]

Originally Posted by Portage_Bay

4,978? I'm at 4106. Guess I'm running on borrowed time!

Where do you go to borrow time? It must be a great business.

[North Baltic sea]

Hi,

here is a copy of seaboard Tony's writing.

"The single most important component on this engine as to proper maintenance that has or has not been done since new is /are the aftercoolers…………..Engine hours are meaningless for this component.

Know anything “real” about part of the engine?

GPH at hull speed are of not concern.. Its at “cruise RPM’s that matters..

At 5100 hours, these are engines are due fro an overhead adjustment.. Maybe 2 hours per engine by a good tech.

As to hours overall—————I am pulling 2 x QSB 5.9 2005 Vintage from a charter boat this Jan–over 30, 000 hours–Heads have never been off and aftercoolers are original w/ the old aluminum cores.. Aloha Spirit–Channel Islands Calif. If he was not getting a grant to move up the EPA T3 QSB 6.7’s, he’d stay with what he has and go for 40,000 hrs…. Solid engine if all is done right & kept up right from Day 1…

As a side note, when I download the ECM as to total fuel burn per engine, I am thinking I’ll see well over 100,000 gallons per engine since new in 2005.."

NBs

[O C Diver]

Originally Posted by Fletcher500

Your posts always end on a sour note when people are trying to answer your questions.

Here is your answer: 4,978.

I have 5,257 since 2016. Should I expect its demise shortly? I'm guessing another 15K to the first overhaul.

Ted