How to determine number of hours on diesel engine

[waterman46]

Originally Posted by J.Kitchens

When I purchased my boat it didn't have an hour meter so I flew in the engine whisperer Volvo keeps on staff in Germany. He placed his hand on the engine block and not even a second after he touched it he jumped back quickly. His face turned white and he told me I needed a new engine immediately. Luckily, Volvo was there for me and I had a brand new engine and gear box installed within a week. I have to say it was worth it; I haven't had an engine problem yet. PM me I'll get you in contact with him.

The guy must have been a great actor for Volvo.

[Cadence]

Originally Posted by Wotname

I personally like this style of an Hobbs meter
https://www.aircraftspruce.eu/hobbs-...eter-85094.htm

But really there is an endless variety of hour meters available and mainly it is a personal choice.

I prefer to wire it so the 12+ve come from the engine ON switch and the 12-ve comes via a oil pressure switch however you may need to confirm if your existing oil pressure switch is suitable (hint - most likely it won't be ). You can add a relay if the existing oil pressure switch isn't suitable rather to hunt down a suitable switch.

However many (most?) don't worry about using the oil pressure switch in the Hobbs meter circuit. The minor downside is the hour meter is ticking over anytime the engine ON switch is on even though the engine might not be running.

A damned good suggestion, using the oil pressure switch for the ground to the meter.

[Dsanduril]

I only have the manual for the 'B' series engines and onward, but if the original -75 is the same then the oil pressure switch is two-wire with +12V fed to the switch. Even stupider, it is closed on alarm, open on good oil pressure - ask me how I know, you can disconnect the cable to get rid of an alarm

The oil pressure in the engine is monitored by a pressure switch. The output signal from the pressure switch can have two distinct positions, high/low, in the same way as a relay output. A pre-set limit value determines when the switch switches from one distinct position to the other one. The switch is closed when the oil pressure is low and when the engine is off. [emphasis added]

[Emouchet]

Here is where to order the hour meter LCD replacement part and a video on how o replace it. Worked great for me. Was able to find out our 1995 engine is only 2000 hours past its rebuild!

http://www.boatstuff.se

https://youtu.be/PFkSwD5-mfw

[jmschmidt]

Cheap oil pressure activated units are easily available. I installed one when the one on my $700 replacement dash board crapped out. I just have to add the two readouts to get the total. If you don't want to do the math you would have leave it connected to a 12VDC source for the number of hours you think it has before installing the gauge in your boat.

[BruceS]

It seems like engine hours has now days gone to equal hours the key is turned on?
For many years I was used to having engine hours being at certain revs.
The Fordson tractor was one engine hour with 1 hour at 1200 rpm.
If it was left idling at 600rpm it took 2 hours to record one hour.
Similar with Caterpillar tractors/bulldozers.
I knew a contractor who charged on engine hours & left the motor running while sitting under a shady tree eating lunch. (Being paid for his lunch?!)

[Cadence]

Originally Posted by swflguy

We bought an 2006 Elan 434 this spring. The digital hour meter no longer works.
My objective is to install an analog hour meter in the engine compartment and reset the meter to reflect the the number of hours currently on the engine.
Any suggestions as to choosing an hour meter, installation and how to determine the number of hours currently on the engine is appreciated.
The engine is a Volvo-Penta D75 saildrive.
Thank you!

If I understand? There is no way to figure out how many hours where lost. Why not put the new meter in at zero and keep the old reading in a log book.
History is history, you're needing the meter for the future maintenance.

[a64pilot]

First problem.
How are you going to “preset” the hour meter? A large point of an hour meter is that it’s not adjustable. I’ve never seen one that was.

Secondly, there is no way at all to determine number of hours on an engine, and it’s irrelevant too, just like miles on a car is.
There are only three things important to an engine, condition, condition, condition.
Even on aircraft where there is a TBO for engines, there is NO evidence that changing an engine based on number of hours prevents engine failures as opposed to condition.

I know that will have people calling BS, but look it up.

[Jim Cate]

While I do agree that the number of hours isn't very significant, you can get a reasonable estimate of worst case usage if you use 100 hours per year as a guess. Unless the boat was in charter or was in long term cruising usage, it is quite unlikely to have had more than this many hours on it.

Jim

[scottydaum]

Keeping track of the "hours" on a diesel engine is good for scheduling preventative maintenance, but to really understand the internal condition of the engine based on wear, one should obtain an oil sample and have it tested at a lab. The main bearings are main of a material that exposes different colors as they wear down. The Oil Analysis can very precisely tell how much use the engine has endured. The whole trucking industry relies on this method. I would not purchase any boat of substantial value without an oil analysis regardless of what the hour meter reads.

[model 10]

Some engines do have life limited parts. Thankfully there are none of those in a boat engine.

[Simi 60]

Originally Posted by Wotname

However many (most?) don't worry about using the oil pressure switch in the Hobbs meter circuit. The minor downside is the hour meter is ticking over anytime the engine ON switch is on even though the engine might not be running.

On switch is on and there is an ear piercing horn on ours and something less offensive on most forcing us to either start the engine or turn the switch off.

[a64pilot]

Originally Posted by scottydaum

The Oil Analysis can very precisely tell how much use the engine has endured. The whole trucking industry relies on this method. I would not purchase any boat of substantial value without an oil analysis regardless of what the hour meter reads.

I hear this kind of thing all of the time, and wish it were true, but it’s not.
I tracked fleets of vehicles and aircraft for 20 yrs with oil analysis, and it’s not worth squat for determining condition of an oil lubricated component.
It is excellent for determining if oil is fuel diluted, or simply worn out, or loaded with soot, or even if it has been contaminated with antifreeze.
In short oil analysis is an excellent tool for determining the condition of the oil, but not for the component.
It has saved the Army no telling how much money by changing trucks oil when it needs it as opposed to a calendar interval, many of the Army’s trucks do a lot of sitting.

Don’t believe me, call Blackstone or other good lab and ask direct questions.

In particular it’s worthless to determine the condition of an engine your looking at purchasing, unless maybe there are several years of historical analyses to compare against, if you have that, and a certain metal is elevated, then maybe, but without a well established baseline you don’t have anything at all.

[a64pilot]

Now properly cutting open an oil filter and inspecting that can tell you quite a lot, assuming of course it wasn’t installed yesterday

[model 10]

I think the Dowsing thing the Volvo guru did should be made easy to understand by everybody. How cool was that?