Wear & Tear Comparison

[Willie12345]

I suspect I may be wrong in my understanding of engine wear & tear, but it seems that inboard gas engines get a lot more wear when compared to their automotive cousins. Is it reasonable to expect the same general life duration (in terms of engine hours) of a automotive engine in a car as it would see in a marine application ? Is the marine application that much more demanding on the basic engine components (excluding unique marine parts) ? Clarification: If the same model engine was places in a automotive application and a marine application, under the same general loading characteristics (torque/RPM/start-stop cycles, etc), would the marine engine wear out first ? (assuming freshwater application)

If this is the case, what are the influencing factors ?

 

[thumpar]

Re: Wear & Tear Comparison

Boat engines get more use like highway miles on a car. Stop and go traffic puts more wear on a motor.

 

[superbenk]

Re: Wear & Tear Comparison

Boats also don't have a transmission like a car so the run at far higher RPMs more frequently. I'd suspect an automotive engine is going to last much longer than a boat because you can't really compare their uses & stresses.

 

[superbenk]

Re: Wear & Tear Comparison

That being said, boat & auto engine blocks are essentially the same, so mechanically the should wear the same under similar loads/stress.

 

[Bondo]

Re: Wear & Tear Comparison

I suspect I may be wrong in my understanding of engine wear & tear, but it seems that inboard gas engines get a lot more wear when compared to their automotive cousins. Is it reasonable to expect the same general life duration (in terms of engine hours) of a automotive engine in a car as it would see in a marine application ? Is the marine application that much more demanding on the basic engine components (excluding unique marine parts) ? Clarification: If the same model engine was places in a automotive application and a marine application, under the same general loading characteristics (torque/RPM/start-stop cycles, etc), would the marine engine wear out first ? (assuming freshwater application)

If this is the case, what are the influencing factors ?

Ayuh,.... Generally speakin', boat motors rarely ever Wear out,....

They are usually Killed by a lack of maintenance, or frozen, 'n busted,.....

My little 4.3l is over 2,000 hours so far, still with solid compression numbers,...

 

[tpenfield]

Re: Wear & Tear Comparison

The difference in fuel usage can give you an indication of 'wear & tear" on an engine . . .

So, if you compare an automobile to a boat . . . you are typically seeing about 10 times the fuel consumption in a boat . So, you could expect 10 times the wear . . .

To Bond-o's point, that is seldom what does a boat engine in though. Usually other factors come into play.

Here is an illustrative link from the Mercury/Mercruiser web site:
http://www.mercurymarine.com/parts-and-accessories/marine-grade-over-automotive/

 

[Oshkosh1]

Re: Wear & Tear Comparison

I think a better comparison is to an engine in small, general aviation aircraft(Cessna/Piper etc)...where the life of the engine is mainly spent at higher, wide-band RPMs/power settings without a transmission per se(although a variable pitch prop does give you more efficent power control).

Aircraft engines have what are called TBO's or "Time Between Overhaul" intervals because mileage is almost irrelevent due to the enviroment they operate in. 1K hours in an airplane is many times equated to about 100K miles if it were seeing service in an automobile where a transmission would keep the RPMs in a fairly narrow band.

Obviously maintenance standards/schedules are much higher in an aircraft...but so are the consequences of the lack thereof!

 

[HT32BSX115]

Re: Wear & Tear Comparison

I suspect I may be wrong in my understanding of engine wear & tear, but it seems that inboard gas engines get a lot more wear when compared to their automotive cousins. Is it reasonable to expect the same general life duration (in terms of engine hours) of a automotive engine in a car as it would see in a marine application ?

Probably. Marine engines usually run at constant RPM and power settings. Automotive engines are operated "all over the chart" But read on.....

Is the marine application that much more demanding on the basic engine components (excluding unique marine parts) ?

Absolutely! A marine engine, although operated at constant RPM for the most part........IS run at FAR higher load than just about ANY automotive engine. Excluding medium & heavy duty trucks and certain light duty trucks that tow heavy loads, automotive (car/LT-truck) engines operate most of the time at a SMALL fraction of maximum power & torque.

Marine engines almost ALWAYS operate at 50-75%-100% of maximum rated power (Just like an aircraft engine) This is not always a bad thing because (normal) oil temp, coolant temp, cyl-head temp etc is usually quickly achieved and the engine is run at those temps. (this promotes longevity) Automotive (car/lt truck) engines frequently DON'T get to normal operating temp before being shut down.

AND, Automotive (car) engines rarely get operated at maximum power (or even 50% power) for very long.

Clarification: If the same model engine was places in a automotive application and a marine application, under the same general loading characteristics (torque/RPM/start-stop cycles, etc), would the marine engine wear out first ? (assuming freshwater application)

Well, they are! (Automotive engines ARE operated in marine applications.) But I don't think you can easily equate the 2

I had a 66 Mark Twain that had a 150 Mercruiser installed (GM 230 cu-in 6-cyl) It ran largely "untouched" (other than normal maintenance) for 39 years before I sold it in 2005. (the hr meter failed in the mid 80's at 1500hrs.....)

If this is the case, what are the influencing factors ?

There's plenty of examples of old 50's cars and trucks with original engines that are still running....... I don't think there's a hard and fast "rule"...... just take care of it (don't let it freeze) and it'll last a "good long time"............