# Hours



## daddyrob4x4 (Jul 16, 2012)

Is there any way to see how many hours are on the motor?


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## Cruzator (Dec 31, 2014)

I believe I saw that when my scanner was hooked up to it. I know it had idle hours, and I believe total hours as well. (This is on a diesel Cruze).


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## Robby (Mar 1, 2013)

daddyrob4x4 said:


> Is there any way to see how many hours are on the motor?


This will get you close: Monday, at the first start of the day, reset one of the two trip meters and restart the timer on the DIC.
The following Monday (or Sunday evening) record the miles traveled and elapsed time.

Divide the one week miles traveled by the elapsed time. Example: 300 miles divided by 20.00 hours = 15
You should see something close to 15 on your average MPH readout.
If this number is close to your average MPH you can use either figure as a multiplier.

Using 15, your average MPH, divide it into your total mileage being displayed.....Lets say you show 30,000 miles.

30,000 divided by 15= 2000.......2000 is the average run time (in hours) for your car.....use the number you arrive at as a baseline and add the elapsed time to that (and reset the timer) with each oil change.
Each entry from that point forward is a actual running time as long as you do not sit in a non running car with the key on since the timer runs anytime the key is on, running or not.


Or, you can just do averages.
For example, construction equipment, aircraft, larger watercraft, stationary engines, etcetera, all have hourmeters.

Most folks have difficulty embracing hours when discussing machines....we need to turn it into something we can relate to.
So, there is a general rule used.......take the hourmeter reading X 32...........32 is a mythical number meaning average MPH, and you may notice this is close to the number that is displayed as average speed on your DIC. (unless it's my car, mostly city, 26 mph for 29000 miles).

But, close enough for averages.
We can do the inverse to create a average......Your car: 30,000 miles divided by 32= 937.5 hours....use that as a baseline and add your actual elapsed time at every reset to create a average, life of car, hours running chart.

Talk about a bunch of useless info just launched into hyperspace!!!!!!!!I gotta get some coffee!

Rob


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## KpaxFAQ (Sep 1, 2013)

My type of driving equals around 200 hours every 5,000 miles.


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## Robby (Mar 1, 2013)

KpaxFAQ said:


> My type of driving equals around 200 hours every 5,000 miles.


Sounds about right......seems 200hrs. works out for most to be 5 to 6000 miles.

Rob


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## obermd (Mar 3, 2012)

OK - Why?


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## Robby (Mar 1, 2013)

obermd said:


> OK - Why?


???????????

Rob


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## obermd (Mar 3, 2012)

Let me clarify, why do you want to know the "hours" on the engine? I'm not a diesel guy so please enlighten me.


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## daddyrob4x4 (Jul 16, 2012)

Yes hours on engine. I am just curious. My 01 Silverado had a hour meter. Just curious if my 15 cruze diesel had one.


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## Robby (Mar 1, 2013)

Hours of operation are a more accurate method of determining when service is required.
It can also help gauge the useful engine life.

Example: A police car will spend the majority of its day idling.......between tasks.
The odometer may only show two thousand miles have accrued, but the hourmeter is showing 600 hours.
This means that, although the chassis has only experienced two thousand miles of usage, the engine (and its oil) have experienced approximately 6000 miles of operation.
So, for this service, the odometer is useless.

The majority of machines have maintenence intervals expressed as hours used.......even your lawn mower or snow blower manual recommends service at X hour intervals.

Rob


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## Robby (Mar 1, 2013)

daddyrob4x4 said:


> Yes hours on engine. I am just curious. My 01 Silverado had a hour meter. Just curious if my 15 cruze diesel had one.


I find this subject interesting since I had a similar discussion with my son (the one that owns the demolition company) regarding engine service life based on hours.
All of his heavy equipment, of course, has hourmeters and all services are performed based on time.

But the confusion comes about with small equipment.....the things I repair for him, such as Husqvarna Cut off Saws, chain saws, concrete cutters, asphalt cutters and so on.

As stated, all machines have a service life based on time......and usage.
Examples: Leaf blowers- 50 hours, Cut off saws-300 hours, Generators-500 hours, Lawnmowers- 150 hours, Snowblowers- 300 hours.

Each small engine has a EPA compliance label affixed somewhere on it. This label shows the EPA test catagory (Bin) and how many hours of operation the engine is designed to remain in compliance.
This is the actual service of that engine being operated at FULL power, maximum design load, before it falls out of compliance.

These can only be considered baseline though, since very few of the examples I've given operate at full power when in operation. To be more precise,that means full power at full rated load.

The baseline information helps me though, because I track the usage of each piece, as average usage time.
Even though the cut off saw is on the job, the laborer is generally only using it for five hours, and those five hours may only be three at wide open, full power/load usage.
As time accrues, I know when it is time to start taking compression tests because ring replacement time is getting near (these are two strokes BTW).

In general, I can achieve just short of a 900 hour service life out of the unit.....this means it will get two sets of rings, possibly a piston, and two sets of crankshaft seals. These units cost a bit over $1200.00 each, so the light reconditioning can get three times the design life out of it.

That is just a background story about how hours/machines tie together.

Lets move over to our cars.
All-any-every four stroke, gasoline burning auto engine has a design life of 3000 hrs.
Yep, that's it........100,000 miles................Yeah, I know, your last car went over 300,000 Rob, wtf are you talking about?

Well, that is 3000 hours at maximum load, producing maximum power.......As much as we like to stroke ourselves saying we pound the daylights out of it, drive it like we stole it, yada yada, it may actually produce maximum power at maximum load for five minutes of its entire service life.

Knowing this helps you understand why a engine (well maintained) can go four and sometimes five times beyond its design parameters.
It is rarely working very hard.
The Cruze, for example, on a flat road, windless day only requires about 25 to 30 hp to maintain 60 mph.....so, we can see it is hardly ever really working up any sweat.

A diesel engine has a design bogie of 9000 hrs before it starts to fall out of complience.....again, maximum power at maximum load.
The extended lifespan is directly attributable to the fact diesel fuel is a bit of a lubricant and as a result, piston rings live a very good, lubricated life.
This is why million mile and beyond diesel lifespans are reported.......diesels die because their bearings wear out, gassers die because their rings wear out. 

Falling out of compliance is a ring specific event btw.....blow by, due to wear, is what pushes the engine out. 

So, it is interesting to talk about the miles you have attained on the chassis, but I find it amazing when I run across the extremely high time engines.......it speaks volumes about how it has been used and maintained.

Fun stuff if you're a machine nut like me.

Rob


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## boraz (Aug 29, 2013)

there is a timer page in the DIC, if you activate it, it will show hours that ignition is on.

DIC also has two trip computers, set one for trips, the other for lifetime....itll show distance and avg speed...simple math will get you hours

not much need for hour meter on a modern diesel car, its not sposed to idle unlike a commercial diesel vehicle running a PTO or such.


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## KpaxFAQ (Sep 1, 2013)

Yeah I reset my trip timing at the same time I changed out to get a rough estimate. Works out to about 4000hrs per 100k for me which is nothing for how easy of a life this motor has in this car as Robby pointed out. 300k should be a piece of cake for the main internals of this cars engine. All the other parts...who the **** knows


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## Robby (Mar 1, 2013)

Here in the North the rust worm gets it before it is even close to worn out.

Rob


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## boraz (Aug 29, 2013)

KpaxFAQ said:


> Yeah I reset my trip timing at the same time I changed out to get a rough estimate. Works out to about 4000hrs per 100k for me which is nothing for how easy of a life this motor has in this car as Robby pointed out. 300k should be a piece of cake for the main internals of this cars engine. All the other parts...who the **** knows


the egr is main enemy of the engine


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## Robby (Mar 1, 2013)

boraz said:


> the egr is main enemy of the engine


Not really......wanna know why?

If you say yes, I'll answer tomorrow...a bit long winded.

Rob


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## daddyrob4x4 (Jul 16, 2012)

Robby said:


> Not really......wanna know why?
> 
> If you say yes, I'll answer tomorrow...a bit long winded.
> 
> Rob


Yes


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## Robby (Mar 1, 2013)

daddyrob4x4 said:


> Yes


OK then......happy Tuesday btw.
History:

The Exaust Gas Recirculation valve, or EGR, was first used in 1973, gasoline fueled, new car production.
The intent was reduction of nitrogen ozides (NOx).
By introducing a metered amount of inert gasses (exaust) with the fuel mixture the temperature of the burn in the combustion chamber is reduced, in so doing, lowering NOx production as a result of combustion.

The early years were a disaster.....cars ran awful, fuel mileage tanked, I made a small fortune disabling the things.....think about it.....the engine was being fed its own exaust......how would you respond if you ate your own exaust (yecccchy).

As time and technology moved on into the early eighties, the EGR systems became better integrated and as time went on I was beginning to find cars would now run better if the system was not disturbed......specifically, most cars would develop spark knock if the system was disabled.

So, I decided to get further educumated on this thing.

Turns out, this device has morphed into a valuable contraption by allowing extremely lean fuel/air mixtures, yet still lowering combustion temperatures, and reducing the tendency to knock.......what made it so, was the introduction of fuel injection and computer controls.

A lean fuel/air mix, by nature, will have a strong tendency to knock due to high heat and 'dead space' between the fuel and air molecules.

From this point on, the discussion will include diesel engines, since the technology has entered that side of overall picture and the problems,
that are being addressed are similar to both fuel types.

Early engines depend on tightly packed molecules of air and fuel so that when combustion occurs the flame (fuel burns, not explodes) can propagate evenly across the combustion chamber.......if it does not, a ignition knock will likely occur. Ignition knock refers to the moment fuel is injected (diesel) or a spark is introduced (gasoline).
At that moment, if the fuel molecules are too far apart a multiple flame front can occur, meaning combustion occurs not only at the normal start point (injector pre-chamber or spark plug) but at the leanest area of the combustion chamber due to the leanness and heat of compression.
When the two flame fronts collide, an explosive, uncontrolled force occurs and the piston is the recipient......it gets hit, rather than pushed.
Over time, this destructive force breaks pistons.....also, that explosive force makes a 'no power' stroke and lastly, not all the fuel burned and was exausted out the tailpipe.
So, it is destructive, provides no power, and increases emissions.......the various sensors go insane trying to make adjustments downstream.

It was learned that by providing inert gas molecules into the lean mixture, a chemical 'chain' is created......the cylinder is fully packed with molecules......air, fuel, inert gas.
This 'daisy chain' allows the burn to propagate across the combustion chamber by creating a path and at the same time, cools the burn and reduces NOx emissions. 

The component that I used to despise has become a rather important emission device that enhances fuel economy, protects the engine, and just happens to reduce noX production at the same time, be it diesel or gasoline.

Hope that did some good.....if I need to be more specific just ask.

Rob


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## spacedout (Dec 7, 2010)

Robby said:


> Most folks have difficulty embracing hours when discussing machines....we need to turn it into something we can relate to.
> So, there is a general rule used.......take the hourmeter reading X 32...........32 is a mythical number meaning average MPH, and you may notice this is close to the number that is displayed as average speed on your DIC. (unless it's my car, mostly city, 26 mph for 29000 miles).


Hours can show why a high mileage car may actually have less wear than a low mileage one. Take your average speed(26mph) for example and my 39mph average speed. Over the same 100,000 miles I accumulate 2564 hours where you hit 3846 hours.


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## diesel (Jun 8, 2013)

@Robby nice interesting and informative writeup.


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## daddyrob4x4 (Jul 16, 2012)

spacedout said:


> Hours can show why a high mileage car may actually have less wear than a low mileage one. Take your average speed(26mph) for example and my 39mph average speed. Over the same 100,000 miles I accumulate 2564 hours where you hit 3846 hours.


Exactly. I have a 2012 cruze eco that has 178000 on it. All highway. Probably low hours for the mileage. A lot of people don't understand that.


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