Engine hours

[Robbie430]

Quick question, would you have any concerns with 14 year old Cummins Diesel's with only 100 hours on them?

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[HappyMdRSailor]

Originally Posted by Robbie430

Quick question, would you have any concerns with 14 year old Cummins Diesel's with only 100 hours on them?

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I would be ELATED!!!

Overall visual condition is of course an important factor... Standard checks... Operation... etc...

[Robbie430]

I was elated! I just wasn't sure if sitting that much would be harmful or not.

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[Southern Star]

It would depend upon whether they had been used regularly (if sparingly), or left to sit for years on end.... Is the oil clean? If they had been put away with fresh oil, then chances of internal damage is reduced (used oil contains sulphur and various other chemicals that will cause corrosion over time). You will, however, want to do another oil change before trying to start it up as there is apt to be water (from condensation) in the oil. And if they have been sitting for years, don't even think about using the exisitng diesel fuel without polishing!

As has been pointed out, visual inspection is also important. Depending on how well the engine compartments were ventilated, observable rust may have formed on the engines and if so, there is every reason to believe that it will have formed in the alternators and starter motors.

Brad

[a64pilot]

My engine is 28 years years old and when I got the boat almost two years ago it supposedly had 500 hours on the engine, that did seem to jive with receipts over the years stating hours. (Yanmar 4-JHBE)
In two years I've put a couple of hundred on it, and so far it seems fine, except there is a lot more rust than I like in the freshwater cooling side, but that can happen in five years if you don't change coolant.


Myself, I'd rather have a 14 yr old Cummins, than a new Volvo

[Strait Shooter]

My boat had a 34 year old Perkins M50 with 260 hours on it when I purchased her.
The heat exchanger failed at 310hrs, and I had fuel issues at first, but otherwise I couldn't be more pleased.
After a little attention it has become a very reliable, great running engine.

[John_Trusty]

The assumption here is that the 100 hours on the meter indicates that the engine ran for just 100 hours in its life. For fifty bucks new (or $20 on eBay) I can buy an engine hour meter and make it say whatever I think the buyer will believe. It is not like you know how long that meter was connected to that engine over the past 14 years. Do you trust that PO?

[Liam Wald]

Double edged sword...
Diesels are really happiest when they are run frequently and run hard.
An engine that gets stared and run for 10 minutes to leave a harbor and then shut down may have fewer hours but gets more wear than an engine that gets started and run for 2 hours with a heavy load. They like to get good and hot (and then have a cool down period) before shutting down.
Personally I would rather have a 10 year old engine with 1500 hours that had been started 500 times than a 10 year old engine with 100 hours that had been started 500 times.

[a64pilot]

Originally Posted by John_Trusty

The assumption here is that the 100 hours on the meter indicates that the engine ran for just 100 hours in its life. For fifty bucks new (or $20 on eBay) I can buy an engine hour meter and make it say whatever I think the buyer will believe. It is not like you know how long that meter was connected to that engine over the past 14 years. Do you trust that PO?

It's also exceedingly easy to simply unplug one, but when you have receipts of engine work that show a slowly increasing hour reading over they years, it might be a low time engine, but I always preface saying my engine was a 500 hr engine by saying supposedly, because truthfully, you never know.

[Sailmonkey]

I'm always leery of low hours. All that time just sitting with seawater in the exhaust, wet oil, corrosion in heat exchangers, etc


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[a64pilot]

Originally Posted by Sailmonkey

I'm always leery of low hours. All that time just sitting with seawater in the exhaust, wet oil, corrosion in heat exchangers, etc


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Me too, but they are also an indicator of boat usage, a high time motor, means the boat has been used a lot.
My boat I'm sure was a Dock Queen, just too many indicators point toward that, low engine hours was just one.

[chris95040]

Originally Posted by Liam Wald

Personally I would rather have a 10 year old engine with 1500 hours that had been started 500 times than a 10 year old engine with 100 hours that had been started 500 times.

In both of those scenarios, the engine goes through the "cold startup" wear+tear 500 times.

I'd therefore argue the one with less overall hours is in better shape, although probably insignificantly so, since you are right, the extra hours didn't hurt as much as the 500 starts did. Once they are warm the wear and tear diminishes.

In one scenario, the engine is started, and then proceeds to run for an average total runtime of 3 hours per session. In the second scenario, it only ran 12 minutes per session.

Both had 500 sessions over 10 years.

The claim that the one with the 3 hour per session usage is in better shape than the one with the 12 minute per session usage suggests that in those 3 hour runs, the engine was magically healing itself of wear + tear that it experienced in the first 12 minutes. Its just not true.

[Robbie430]

Thank you all for the help!

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