I6, V8 diesels in OTR and off road applications

[DZink24]

call me naive, dumb, or misinformed, but is it safe to say that the majority of all diesel engines in production the past 20 years (or forever) are inline 4,6,or 8 cylinder motors? whether it be in a excavator, bobcat, or OTR 18 wheeler, i have always assumed that they were in an in-line setup. reason i bring up this topic, last week i was working with a friend who owns a D-max, and he blew my mind when he assumed my truck was an 8 cylinder (we never specified inline or V, i was speechless at that point). he tried telling me that one of our fire trucks with a Detroit is an inline 8 cylinder. while he may be right, i thought the majority of all "large" diesel motors are 6 cylinders. and i have heard others talking of big 10 wheel dump trucks running V-8s, maybe MACKs?? i have driven fire trucks for the past 15 years, and tractor trailer for the past 8, and have NEVER come across a heavy duty V-8 configuration, only the tried and true I6 :-laf



and the heavy duty in italics is a shot at our Ford and Chevy friends.

 

[The patriot]

The large v8 diesel engines never made it around here in an OTR truck.

I suppose they may be more popular somewhere else.

The load conditions will dictate the size of the engine and if it will be accepted/successful.

Example:

Trucks running 120K lbs up & down the rockies will be more suited to larger engines than a truck loaded to 80K running Fla to Maine. And what I was told they'll be more accepted because theyre properly loaded.

Yes, the in line 6 was about all we ran back in the day.



JM. 02

 

[Mhannink]

well it really depends, inline 6's have been the pedominant design, but in the 60's and 70's there were v8's, they were mostly cat 3408's in heavy hauls and you could find detroit 2 strokes that were any number v configurations, mostly in trucks it was 6 and 8 cylinder. it really all depended on application, power needs, and packaging. another heavy duty app is earth movers and construction equipment, there you would see a lot of v8's 10's 12's and 16's, though i think it was mostly 8's and 12's and only when the power requirments were more than a 4 or 6 cylinder could make.



i think your buddy has correct information, he just has it all mixed up, v configs were used a fair amount in the old days because the power output for the area it took up was good, but really anything over a 6 cyl is going to be in a v, there are inline 8's but i think that was really only in some old packard auto's and they were gas, there could be some in heavy duty apps but i dont know of any. inlines tend to be 4 and 6, v's tend to be 6 and up. hope that helps

 

[HBarlow]

You are not naive, dumb, or misinformed. For the last 30 years or more all OTR truck tractors have used inline six cylinder engines. I believe all farm equipment and road building equipment does also.

The simple reason why inline six cylinder engines are in widespread use is they are less expensive to build and repair, more practical to work on, more economical to operate and overhaul, are capable of providing one million miles of service, and they produce huge torque at clutch engagement rpm and max torque just above idle.

V8 diesels are ONLY in use for transportation applications in Furd and Obama Motors light trucks. They are throw away engines compared to our Cummins engines.

An old friend of mine who has been a Chevrolet truck salesman for 30 years or longer was dumb enough to try to sell me a GM/Isuzu diesel several years ago. I laughed at him and told him when all OTR tractors began running V8 diesels to give me a call. He said lots of them were running V8s! He was so dumb he thought that the OTR tractors with dual exhaust stacks behind the cab were V8s!

A typical loyal nobama motors fan and salesman.

 

[DZink24]

when i was with my buddy, this whole conversation started when he was telling me how a few of his injectors were trashed, he decided to just go ahead and replace all 8, as he got a good price from the inside. . i joked and said "i would have only had to buy 6" :-laf

 

[Nyoest]

There are several v 8 diesels but they are the exception and not the rule.



Cat 3208 could be found in scrapers, medium duty fords and Oliver tractors.



Cummins 903 were placed in steigers first tractor, the tiger.



Perkins v 8s were also placed in Massey ferguson tractors, the one I'm most familiar with is the 1150.



Cat bulldozers d 9 and d 11 run v 8's. Oddly enough the d 10 uses a twelve cylinder!?

 

[Mhannink]

thats funny, bet he didnt like that. like harvey said you are not dumb naive or misinformed, you simply did not know nothing wrong with that. harvey is also correct about why inline 6's are used most often, they have i think it is 40% fewer moving parts thats less to go wrong. in trucks they are a little easier to overhaul and with fewer parts definatly cheaper. also they tend to get better fuel mileage while still providing big power for pulling.



however harvey v8's are not ONLY for fords and chevy's, cummins was a few years ago working on v6 and v8 engines for the dakota and 1500 sized trucks, they may have pulled the plug on that by now though. there are heavy duty applications with v8's and even v12's, the 3408 was used in many heavy haul trucks in the 80's i think, cause it could build big power cheaply and reliably, the compitetion at the time was the cummins kta and ktta, they were i6's and had massive power, and the best jakes on the market, however they cost a lot more than a 3408 to overhaul, and were higher maintence, and the cat could go the distance, i think it was new better technology in inlines with more power and better fuel mileage that phased them out. same with the detroit 2 strokes, in their day they had the best power to weight ratio and many were v engines, even pancake engines, the ranged in size from 4 up to 16 or 20 cylinders with a displacement of 53 to somewhere around 102 cu inches per cylinder. they could be found all over the world in trucks, pumps, mining, drilling, power gen and many others. i know in dozers and large excavators they ran v engines, typically 8 or 12 cylinder. most power gen engines are v's and a lot of mining and drilling equipment have v engines, as well as marine.



the main reason why inline 6's are used so much is they produce big power on minimal fuel, its an effecient design, however i would argue about reliability, that boils down to maintenece period, cat and cummins are not going to build big bore v configured engines as throw aways especially when they are in marine applications. maintenence is key, i will agree with you though that inline 6's are probably cheaper to maintain then v8's. also the b series cummins aka the 5. 9 and now 6. 7 are throw away engines. all engines that are parent bore block (cylinder liners cant be replaced) are considerd throw away, so before you go bashing on ford and chevy keep that in mind.

 

[Mhannink]

There are several v 8 diesels but they are the exception and not the rule.



Cat 3208 could be found in scrapers, medium duty fords and Oliver tractors.



Cummins 903 were placed in steigers first tractor, the tiger.



Perkins v 8s were also placed in Massey ferguson tractors, the one I'm most familiar with is the 1150.



Cat bulldozers d 9 and d 11 run v 8's. Oddly enough the d 10 uses a twelve cylinder!?

thats older equipment i think, when i was working for cat a couple years ago we had some new d8's 9's and 10's they all had inline engines the d10 had a c18 i think. you are right about the older ones though many had 3400 series 8 or 12 cylinder engines, also the scrapers i saw mostly had 3306 and 3406 engines but maybe 3208 was in the small ones, still considered heavy duty.



cummins did have a few v8's back in the day, the 903 and there was another one but i can remember it maybe it was a 555?



ive only seen one perkins v8 in my life, it was a 3111 i think maybe it was a 3118.



in fact in cat engines it is really easy to tell how many cylinders the engine has, just look at the last two digits i. e. 3306 3408 3512 the first two numbers tells you the engine series, like cummins b, c, l, m, etc. the last two tell you the number of cylinders. the only exception to this is the 3100 series, here the middle two number tells you the cylinder displacement, i. e. 3116 is 3100 series 1. 1 liters per cylinder and six cylinders. 3126 3176 3114 etc.

 

[Nyoest]

Ya my bible is a little old. It's from '99. Way back when the d 9 was a 3408eta the d 10 was 3412ta and the d 11 was 3508bta.

3114, never saw one of those. I never thought they could build a bigger pooch than the 3116/3126.

 

[Mhannink]

Ya my bible is a little old. It's from '99. Way back when the d 9 was a 3408eta the d 10 was 3412ta and the d 11 was 3508bta.



3114, never saw one of those. I never thought they could build a bigger pooch than the 3116/3126.

yeah the old ones where, i never saw a d11, i did not think the 3500's held up to well in mobile apps, too big and sensitive to chassis twist, its not impossible though.



its funny i actually like the old mech 3116 3126, i know they sold a lot of cummins, but if you personaly know what your doing and have the tools you can make them dream engines in medium and light duty apps. they do require a lot of tlc and you will be under the hood a lot tuning, but those suckers could run when they were set up right. the 3114 was just a baby, i knew a guy put one in a ford pickup, he said it ran like a champ and he couldnt believe how much it would pull and accelerate for a 4. 4 liter engine. he wasnt going to win any races but he liked its performance.

 

[Nyoest]

There in lies the rub most people don't have the time or wear withall to set them up. Or the $1,600 kit to set the injectors. For out of the box performance durability and economy I'll take the 5. 9 over the 3116. But to me the small kitties are all yellow.....

 

[HBarlow]

thats funny, bet he didnt like that. like harvey said you are not dumb naive or misinformed, you simply did not know nothing wrong with that. harvey is also correct about why inline 6's are used most often, they have i think it is 40% fewer moving parts thats less to go wrong. in trucks they are a little easier to overhaul and with fewer parts definatly cheaper. also they tend to get better fuel mileage while still providing big power for pulling.

however harvey v8's are not ONLY for fords and chevy's, cummins was a few years ago working on v6 and v8 engines for the dakota and 1500 sized trucks, they may have pulled the plug on that by now though. there are heavy duty applications with v8's and even v12's, the 3408 was used in many heavy haul trucks in the 80's i think, cause it could build big power cheaply and reliably, the compitetion at the time was the cummins kta and ktta, they were i6's and had massive power, and the best jakes on the market, however they cost a lot more than a 3408 to overhaul, and were higher maintence, and the cat could go the distance, i think it was new better technology in inlines with more power and better fuel mileage that phased them out. same with the detroit 2 strokes, in their day they had the best power to weight ratio and many were v engines, even pancake engines, the ranged in size from 4 up to 16 or 20 cylinders with a displacement of 53 to somewhere around 102 cu inches per cylinder. they could be found all over the world in trucks, pumps, mining, drilling, power gen and many others. i know in dozers and large excavators they ran v engines, typically 8 or 12 cylinder. most power gen engines are v's and a lot of mining and drilling equipment have v engines, as well as marine.

the main reason why inline 6's are used so much is they produce big power on minimal fuel, its an effecient design, however i would argue about reliability, that boils down to maintenece period, cat and cummins are not going to build big bore v configured engines as throw aways especially when they are in marine applications. maintenence is key, i will agree with you though that inline 6's are probably cheaper to maintain then v8's. also the b series cummins aka the 5. 9 and now 6. 7 are throw away engines. all engines that are parent bore block (cylinder liners cant be replaced) are considerd throw away, so before you go bashing on ford and chevy keep that in mind.

You are technically correct but wrong in a practical sense.

I say the V8s are throwaway engines because they provide very short service lives if used for work.

The actual service life of a Sick. Ohh Furd was only a little over 100k miles if used for commercial trailer towing and that limit was reached after lots of highway breakdowns and very pricey warranty repairs.

The Isuzu engines were okay to 300k miles with two or more complete sets of replacement injectors and at that mileage the entire truck was junk. OM only claimed about 250k miles to overhaul. The two Dodges I used when transporting, an '01 HO/six speed had 325k miles on it when I retired it and was in outstanding shape. The mechanic who maintained it for me owns it now with about 360k showing. No worn out upholstery, dash, window switches, door locks, good paint, perfect mechanical condition. No major repairs.

The '06 I owned looked and drove like a new one at 230k miles when I sold it. I know of several who have put 500k miles and more on them. TDR member GAmes put about 850k on his '97 12 valve before he replaced the engine due to blowby and oil consumption. I have another friend who put 950k on a '95. A few RV transporters have reported over 1 million miles without major overhaul.

In many cases owners report high mileage Cummins can simply be honed and new rings and bearings replaced.

There is no comparison between the Dodge-Cummins and the other brands unless stoplight to stoplight drag racing is your interest and even then the Cummins can be made pretty quick.

 

[NIsaacs]

I don't think the 5. 9 Cummins was ever considered a throw away engine. It is used everywhere in everything. Like the 350 chevy, oem and aftermarket parts are available almost anywhere.



Since the pistons are available in two oversizes, rods and mains in four undersizes and crank thrust in two oversizes, it is/was always designed to be rebuilt.



The fact of non replaceable liners was on purpose, to keep the displacement up and size/weight down. Also it doesn't require treatment of the cooling system like wet liner engines do.



Nick

 

[RustyJC]

How about V-20 industrial diesel engines? Below is one of our company's products. The 6 and 8 cylinder versions of this engine model are inlines; the 12, 16 and 20 cylinder versions are vee configuration. A couple of the primary reasons are crankshaft torsional stiffness in very long inline engines and physical package size.



Rusty

 

[mwilson]

What RPM is the sweet spot on that thing?????

 

[RustyJC]

It's rated 8450 BHP @ 400 RPM continuous duty (that's synchronous speed for the 60 Hz AC generator it's driving). A 10% overload is permitted for 2 hours out of every 24 hour period (DEMA rating). 15. 5" bore x 22" stroke, turbocharged, 4 valve cylinder heads, individual camshaft-driven Bosch jerk pump injectors on each cylinder, etc.



This engine can run as a straight diesel or a gas/diesel (96% natural gas, 4% diesel for pilot ignition) with an on-the-fly switchover between modes. It can also run as a spark gas engine by replacing the injectors with spark plugs.



Rusty

 

[Mhannink]

There in lies the rub most people don't have the time or wear withall to set them up. Or the $1,600 kit to set the injectors. For out of the box performance durability and economy I'll take the 5. 9 over the 3116. But to me the small kitties are all yellow.....

thats why they sold a lot of cummins engines, i would take the 5. 9 too, but i like those little cats and they are fun to play with, but i enjoy doing maintenece.

[/U][/I]



You are technically correct but wrong in a practical sense.



I say the V8s are throwaway engines because they provide very short service lives if used for work.



The actual service life of a Sick. Ohh Furd was only a little over 100k miles if used for commercial trailer towing and that limit was reached after lots of highway breakdowns and very pricey warranty repairs.



The Isuzu engines were okay to 300k miles with two or more complete sets of replacement injectors and at that mileage the entire truck was junk. OM only claimed about 250k miles to overhaul. The two Dodges I used when transporting, an '01 HO/six speed had 325k miles on it when I retired it and was in outstanding shape. The mechanic who maintained it for me owns it now with about 360k showing. No worn out upholstery, dash, window switches, door locks, good paint, perfect mechanical condition. No major repairs.



The '06 I owned looked and drove like a new one at 230k miles when I sold it. I know of several who have put 500k miles and more on them. TDR member GAmes put about 850k on his '97 12 valve before he replaced the engine due to blowby and oil consumption. I have another friend who put 950k on a '95. A few RV transporters have reported over 1 million miles without major overhaul.



In many cases owners report high mileage Cummins can simply be honed and new rings and bearings replaced.



There is no comparison between the Dodge-Cummins and the other brands unless stoplight to stoplight drag racing is your interest and even then the Cummins can be made pretty quick.

you are looking only at the fords and chev's both of which are actually medium duty diesels, the navistars actually did pretty well in some of the international trucks, not as good as the cummins but i have seen many of them go the distance paticuarly the 7. 3, in fact its the only engine i have ever owned that i could not break (7. 3 idi that was cranked up why too high for the components), and i really did try. we have one in a 450 ford with 200k and only a couple injectors have been replaced in that time span, even with having run gasoline through them. i have not dealt with the duramax much so i cant really comment on its abilities, but i have seen a lot of 7. 3 v8's run hard and put away wet, and they come back for more, they do stack up against the cummins pretty well.



this is not the point though, the original poster asked about the use of 8 cylinder engines in heavy duty applications, and the fact is they are there and used, the inline 4 and 6 do tend to last a little longer and they are cheaper to rebuild, and burn less fuel for their power and size. this is why they are so widely used, however depending on demands and size requirements v8's are used a lot in heavy duty, and they go the distance like any inline, provided they are maintained correctly, but the inlines have to be maintained just the same.

I don't think the 5. 9 Cummins was ever considered a throw away engine. It is used everywhere in everything. Like the 350 chevy, oem and aftermarket parts are available almost anywhere.



Since the pistons are available in two oversizes, rods and mains in four undersizes and crank thrust in two oversizes, it is/was always designed to be rebuilt.



The fact of non replaceable liners was on purpose, to keep the displacement up and size/weight down. Also it doesn't require treatment of the cooling system like wet liner engines do.



Nick

throw away means it is cheaper to buy a new or remaned engine and install it then to overhaul the one you have, the cost of overhauling a small 6 cylinder engine in relation to the cost of buying a new one is not as big as the cost of rebuilding a big 6 and its relation to a new one. example, a brand new 5. 9 from cummins is i think 10 grand, to rebuild that same engine costs about 4 grand. a isx lets say costs about 50 grand, to rebuild it costs about 8 grand. your better off throwing away the small engines and getting a new one than you are rebuilding it. hence the term throw away engine. pretty much all parent bore blocks are throw aways.



the ford engines are medium duty found in internationals, they can be rebuilt just like the cummins can, all the parts are available like the cummins, you can buy remans just like cummins, its all there no real difference.



you are right though about power to weight with parent bore blocks, that is a consideration along with the coolant treatment vs wet sleeve, but it all comes back to the engines are not going to be rebuilt and run like the bigger ones are its just not cost effective.

 

[HBarlow]

I'm not sure what you were attempting to say. You both adopted my agument as your own and attempted again to refute it.

I repeat my earlier statement. V8 diesels used in light truck applications are throw away engines. Cummins ISBs are not. They provide very long service as new and can easily and cheaply be freshened up or rebuilt.

Furd 7. 3s, 6. ohhs, 6. 4s, and now 6. 7s are not now and never were medium duty engines. Look at the engine tag and you will clearly see light duty. Not even Furd or obama motors ever claimed their engines were medium duty.

Neither is a Furd F-450 a medium duty truck.

 

[bheiting]

Correct me if I'm wrong, but I don't believe our Dodge engines(at least in the pickups) are the same as the medium duty commercial ISB engines. There are at least two factories producing the 6. 7s. Columbus produces the pickup version only, and I believe there is a reason for that.

 

[HBarlow]

I have read or heard nothing about the long block being different or produced in a separate plant. I am skeptical but can't prove that is incorrect.

I have what you are calling a different engine. It is an ISB6. 7 also. The only difference I am aware of is different software programming that tunes it to 305 hp and 610 torque. The other differences are in the emissions system with my cab and chassis having less garbage hung on it.

My truck is a Ram 3500. It uses the identical engine and Aisin transmission the so-called medium duty Ram 4500/5500s do. The Ram 4500/5500s are a quasi-MDT but barely. They are nothing like a real truck purchased from FL or IH, or even Furd F-650/750s with hundreds, perhaps 1000 options for everything from springs to lights. The 3500/4500/5500 are certainly capable and fill a need but don't compare with genuine MDTs.