What motor lasts longer

[MBTRAC]

Hmmm. I wonder if a closer comparison might come from Europe where the proportion of diesel automobiles is very high. The uses of these vehicles would be very similar, so a comparison of maintenance and/or lifespan would be closer to an apples-to-apples comparison.
Now the question is, "does anybody have these data for Europe?"
BOB

Unfortunately we're increasingly comparing "apples with oranges", IMO any European maintenance/lifespan statistics are not relative to US, Canadian, Australian ..etc markets for many varied reason's, including:-
- Most European passenger vehicles/SUV engines are under 2.5litres (c.153CI) for historical reasons of capacity linked road taxes & rarely exceed much beyond 3litres *c.183CI)
- Geography/Population density means than annual European mileage is much less, with a predominance of short hauls often where the engine does not reach/sustain operating temperatures with consequential effects on wear/durability
- Still the preference for manual gearboxes in Europe, in unskilled hands an auto is more sympathetic to the narrow lower RPM/high torque ideal operating characteristics of a diesel engine
-..etc...

I'd suggest most likely "apples to apples" would be the same vehicle, similar engine capacity/output/performance characteristics - maybe a global comparison of say the 2006 model year on BMW X5 3litre inline 6 petrol (272hp) & diesel (265hp) as they shares some common engine components, similar weights, technical architecture & performance characteristics, albiet torque/gearing differs..
Maybe over to those high mileage X5's owners for input/experiences.....:anyone:.

 

[john_bud]

I was trying to install the thought that if you run a gas engine at the same design rpms, stroke, etc of a diesel it may last a lot longer than the perception most people have.

Please define "same amount of work."

I'm not biased either way, I have a diesel engine, gas engines, and a multifuel engine that will run on gas or diesel. I just know that the characteristics of each are very different and I need an all-things-equal comparison criteria so I can put my head around it.

Your thought was good, but the example was poor. If you change it to a gas engine in a car going down the freeway but instead of being in OD at 75 mph, put it in front of a 20k trailer load with 4 stuck brakes in a stiff headwind and the car is in 1st gear at the red line rpm. How long will that engine last? I don't KNOW either, but my guess is that it will self destruct in hours to days. Your typical tractor engine pulling a bottom plow is at the same type of load, but it is expected to last 10,000 hours in that situation or more. Often much more.

 

[94BULLITT]

Your thought was good, but the example was poor. If you change it to a gas engine in a car going down the freeway but instead of being in OD at 75 mph, put it in front of a 20k trailer load with 4 stuck brakes in a stiff headwind and the car is in 1st gear at the red line rpm. How long will that engine last? I don't KNOW either, but my guess is that it will self destruct in hours to days. Your typical tractor engine pulling a bottom plow is at the same type of load, but it is expected to last 10,000 hours in that situation or more. Often much more.

What about a gas engine on a old tractor? A tractor engine is different than a automotive application, a tractor can be ran full throttle all day long and not hurt.

 

[JoeBuyer]

How about these old Masseys? Gas and diesel in the same engine block.

http://www.tractordata.com/farm-tractors/000/7/4/743-massey-ferguson-135-engine.html

They had the AD3.152 and down the page farther the AG3.152. Both used the same block, low revving at 2000 according to this page. Which of these would last longer?

 

[Soundguy]

What about a gas engine on a old tractor? A tractor engine is different than a automotive application, a tractor can be ran full throttle all day long and not hurt.

msny times that's a cooling issue.. you can take a sprts car with a 350hp capable engine and a cooling system capable for 160hp... the car only uses that 350hp on the hard accel in traffic.. otherwise it's pulling 100hp for most stuff...

many tractor cooling systems are rated for the 'rated' hp output of the engine..e tc.

 

[daugen]

How about these old Masseys?
Perkins diesel vs. a Continental gas engine. I'd go with the Perkins, they've been making industrial diesels for a long time.
Which is not to say a properly maintained Continental (is this the same co that makes engines for Piper Cubs and similar?) would not last
exceptionally long, for a gasoline motor...

 

[murphy1244]

How about these old Masseys?
Perkins diesel vs. a Continental gas engine. I'd go with the Perkins, they've been making industrial diesels for a long time.
Which is not to say a properly maintained Continental (is this the same co that makes engines for Piper Cubs and similar?) would not last
exceptionally long, for a gasoline motor...

I have a 67 Massey 135 diesel with 5150 hours and it purrs like a sewing machine.

 

[spruce Deere]

Slightly loaded question but my answer is Diesel.....

 

[94BULLITT]

msny times that's a cooling issue.. you can take a sprts car with a 350hp capable engine and a cooling system capable for 160hp... the car only uses that 350hp on the hard accel in traffic.. otherwise it's pulling 100hp for most stuff...

many tractor cooling systems are rated for the 'rated' hp output of the engine..e tc.

It is mostly due to the car turning more rpm. There automotive engines that are have been built for industrial applications but they are governed. I know a guy that has a chipper with a ford 300 inline six industrial, I think it is even a reverse rotation. There are also SBF Fords for marine use but the have a Marine block.

 

[DarkBlack]

Me thinks the underlying perseptions of almost everyone, makes the diesel seem like the answer. Those perseptions are very skewed.
You have to break that train of thought and realize, that it is not a fair comparison to group 2 engine types by internal or external size, which everyone does by nature. The fact is you are comparing a diesel that weighs almost twice the weight of the gas engine, and costs 2-3 times the price.
Compare same priced gas engine to a same $$ diesel, and you will likelyvfind your longevity results will be very even. Because for the same $$ you can buy a much more powerful gas engine that could be run much less loaded.

 

[LD1]

msny times that's a cooling issue.. you can take a sprts car with a 350hp capable engine and a cooling system capable for 160hp... the car only uses that 350hp on the hard accel in traffic.. otherwise it's pulling 100hp for most stuff...

many tractor cooling systems are rated for the 'rated' hp output of the engine..e tc.

Tractors are also governed to a MUCH lower RPM.

Govern that sports car to 2500 or 3000rpm and then yea, it can run for hours on end at "red-line"

How about these old Masseys?
Perkins diesel vs. a Continental gas engine. I'd go with the Perkins, they've been making industrial diesels for a long time.
Which is not to say a properly maintained Continental (is this the same co that makes engines for Piper Cubs and similar?) would not last
exceptionally long, for a gasoline motor...

I am pretty sure he was talking about the PERKINS gas motor.

And IMO, that is the perfect comparison. Since the Perkins Gasser and Perkins diesel share the SAME block. Actually, they share EVERYTHING they can that isnt relevant to the fuel they burn. And that would pretty makes to ONLY difference the fuel.

 

[john_bud]

What about a gas engine on a old tractor? A tractor engine is different than a automotive application, a tractor can be ran full throttle all day long and not hurt.

Yes, you're correct. They can. But there are some internal differences that are important that make it possible. The old tractor gas engines are in the 6:1 to 7:1 compression ratio. The diesel is 16:1 to 20:1 range. Efficiency goes up with mechanical compression ratio. Operating temperatures also go up with compression ratio (or down with lowered ratio). So to get the gas tractor engine to be able to run all day long for years, it must be designed to run cooler. That means lower CR and that's good for longevity, but bad for fuel consumption. Didn't used to be that big of a deal back in the 50's & 60's, but nowadays....

If you compare good running 1960's vintage gas and diesel tractors (same make & model, just gas vs diesel with both having the same power) the gas engine will typically have a little less HP but use 1.5-2x the fuel per hour doing the same tasks.


But with all that said (and the excellent info in the rest of the posts), we need to remember that today's diesels are built much lighter than they used to be. The construction is a lot better, the machining is dramatically more accurate, but they now run 3000-3500 rpm vs the old ones running 1500-2000rpm and make 30-50% more HP out of the same displacement. Guess we won't know the longevity for sure for a long time. But I know my 50 year old tractors will be running good 50 years from now... I'm less certain of my 10 year old one!

 

[john_bud]

Me thinks the underlying perseptions of almost everyone, makes the diesel seem like the answer. Those perseptions are very skewed.
You have to break that train of thought and realize, that it is not a fair comparison to group 2 engine types by internal or external size, which everyone does by nature. The fact is you are comparing a diesel that weighs almost twice the weight of the gas engine, and costs 2-3 times the price.
Compare same priced gas engine to a same $$ diesel, and you will likelyvfind your longevity results will be very even. Because for the same $$ you can buy a much more powerful gas engine that could be run much less loaded.

Interesting thought. I can see your point, but it seems that most tractors with larger engines are only in larger machines. If they actually would build one like that, it may work that way. Plus, the gas engines (in cars etc) last easily 2-300k with many going 400k or 500k miles where the old ones would be smoking like a bug fogger in 75-100k miles. I guess there's a lot of modern progress we need to consider!

 

[Soundguy]

are you sure about that?

many of the tractor engines I'm compairing have esentially the same block gas or diesel...
thus same size...

on a ford 3000 for instance.. I'd take diesel over gas any day. and on;y part of that reason is because the holley carbs are finicky, and the points are hard to get to..

Me thinks the underlying perseptions of almost everyone, makes the diesel seem like the answer. Those perseptions are very skewed.
You have to break that train of thought and realize, that it is not a fair comparison to group 2 engine types by internal or external size, which everyone does by nature. The fact is you are comparing a diesel that weighs almost twice the weight of the gas engine, and costs 2-3 times the price.
Compare same priced gas engine to a same $$ diesel, and you will likelyvfind your longevity results will be very even. Because for the same $$ you can buy a much more powerful gas engine that could be run much less loaded.

 

[Soundguy]

can't speak for other brands.. but that doesn't specifically hold true for the fords. loking at say a 601 gasser and a 601d.. the d is just a hair less hp.. AND 10more CI.. 134 vs 144. etc.

hard to draw a hard straight line thru this conversation..

If you compare good running 1960's vintage gas and diesel tractors (same make & model, just gas vs diesel with both having the same power) the gas engine will typically have a little less HP but use 1.5-2x the fuel per hour doing the same tasks.

 

[JoeBuyer]

How about these old Masseys?
Perkins diesel vs. a Continental gas engine. I'd go with the Perkins, they've been making industrial diesels for a long time.
Which is not to say a properly maintained Continental (is this the same co that makes engines for Piper Cubs and similar?) would not last
exceptionally long, for a gasoline motor...

They are both Perkins engines. The gas uses the same block as the diesel. I know Massey used the Continental gas as well, but they also used Perkins for gas. My question was about Perkins gas compared to Perkins diesel.

 

[94BULLITT]

Yes, you're correct. They can. But there are some internal differences that are important that make it possible. The old tractor gas engines are in the 6:1 to 7:1 compression ratio. The diesel is 16:1 to 20:1 range. Efficiency goes up with mechanical compression ratio. Operating temperatures also go up with compression ratio (or down with lowered ratio). So to get the gas tractor engine to be able to run all day long for years, it must be designed to run cooler. That means lower CR and that's good for longevity, but bad for fuel consumption. Didn't used to be that big of a deal back in the 50's & 60's, but nowadays....

If you compare good running 1960's vintage gas and diesel tractors (same make & model, just gas vs diesel with both having the same power) the gas engine will typically have a little less HP but use 1.5-2x the fuel per hour doing the same tasks.


But with all that said (and the excellent info in the rest of the posts), we need to remember that today's diesels are built much lighter than they used to be. The construction is a lot better, the machining is dramatically more accurate, but they now run 3000-3500 rpm vs the old ones running 1500-2000rpm and make 30-50% more HP out of the same displacement. Guess we won't know the longevity for sure for a long time. But I know my 50 year old tractors will be running good 50 years from now... I'm less certain of my 10 year old one!

I think the main reason the compression ratio was lower was because of poor gas back in the day.

 

[john_bud]

can't speak for other brands.. but that doesn't specifically hold true for the fords. loking at say a 601 gasser and a 601d.. the d is just a hair less hp.. AND 10more CI.. 134 vs 144. etc.

hard to draw a hard straight line thru this conversation..

True, the old fords diesels seem to be weaker than most. But, the gas engine is still sucking a lot more fuel and the amount of work you can do between the two is about as identical as you can get.

(and yes, its about impossible to draw a straight line conclusion ! Too many cases where either side is equally correct (or equally wrong) depending on what reference you look at. )

 

[MHarryE]

Question regarding European cars and the statement that European driving is not relevant to USA. I lived there, owned a diesel, and drove it 90,000 kilometers or roughly 54,000 miles in 3 years. They drive a lot. For example they say Paris is home to one million cars and 700,000 parking spots so there are at least 300,000 cars on the road at all times and having driven there a lot I have no reason to doubt it. The general rule I heard from my everybody living there was 200,000 km for a gas engine car and 500,000 km for a diesel equivalent. I hated to leave my diesel there when I returned to America because of the fuel economy and drivability. A diesel has so much better low end torque that you never want to return to a gas clunker, but alas that is what we are stuck with in America. After returning to America I still had to travel to Europe a lot for my job, but then it was rental cars. I always dreaded getting stuck with a gas engine car due to the poor fuel economy and difficulty driving a gas manual in heavy traffic - the constant shifting due to the narrow torque band. But in Western Europe the diesel is relatively consistent although my car came with a recommendation to buy only specific fuel brands (and they had a list of about 6 for each country) for longest FIP life. In the USA the fuel is very inconsistent. At work I had access to repair data I could break down in any way I could dream of - dealer, state, type of job, region, etc. Selecting one machine I found a 4 to 1 difference in FIP failure rates between the best and worst regions. Analyzing the claims I found the difference to be fuel related. That is what the car Diesel engine makers told me is there reason for not supplying them in America although they may build the vehicle in America for export to Europe (Voyager minivans were very popular in Europe in the 90's, every one I saw diesel equipped).

 

[daugen]

Analyzing the claims I found the difference to be fuel related.
In the USA the fuel is very inconsistent.

boy would that make interesting info to get online...do you mean one brand "worked better" than another, or were there brands with
irregular cetane ratings, additives??

I think I'll keep giving my Kubota a shot of diesel additive. And I still get to pay $3.40 a gallon locally for diesel. Such a deal.