Jump to content
Model Cars Magazine Forum

Let's Talk Diesels..


Recommended Posts

I don't know much about theses motors, especially concerning big trucks.

My 1st counter with a Diesel motor was as a kid, when Uncle told me as we were crouching in front of 2 monsters in his Sport Fishing boat in South Florida. This was the 60's.  He says, there is only one real Diesel motor.  It's a M.A.N. from Germany.  Later he told me why.  Individual heads, one for each cylinder.

What kind of Diesels then are American made, and what are popular makes, or sizes for heavy trucking.  Are the heads separate?  What make did the trucks in the 60's have?

I know of Caterpillar of course.  Which ones are top notch brand?  Is it a Ford/Chevy type choice? 

Better yet, which brand do you not like?

Thanks in advance, Michael

Link to comment
Share on other sites

This could be a never ending topic. I will try to keep it short. A diesel engine is any engine that runs on diesel, so there is no requirement to have a separate head for each cylinder. Diesels do not use spark plugs like a gasoline engine, instead they rely on very high compression ratios to create the heat needed to ignite the air/fuel mixture in the cylinder.

For years the major diesel engine manufacturers in the US were Detroit Diesel, Cummins, and Caterpillar. A few truck manufacturers such as Mack and Volvo have offered their own engines as well as the other brands of engines for years. Recently Caterpillar has bowed out of the highway engine market due to tighter emission laws that they found difficult to meet. At the same time a few more of the truck manufacturers started marketing engines themselves. International came out with their Maxxforce engines, but they proved to be unreliable and they have since stopped offering the larger versions of this engine (for heavy duty highway trucks). Paccar (mother company of Peterbilt and Kenworth) now offers its own engine as well.

 

Detroit Diesel started as General Motor's diesel division many years ago, and then spun off into its own company. It is now European owned, but still very popular in trucks across the US.

 

In the 1960's, I would say Cummins was the most common diesel engines. Caterpillar didn't seem to become too interested in pushing the highway truck market until the 70's. There were some Detroits back then, but they were not as common as Cummins. There were some other brands running around back then, such as Buda, which no longer exist today.

Edited by KJ790
Link to comment
Share on other sites

Aaron....Geez, that thing does sound rowdy!  A Fire Dept. piece, am I right?  Thanks for the link.  I like.

@KJ, thanks for the insight.  Did the 6-71 blower we know from drag racing evolve then from Detroit Diesel/GM back then? 

Link to comment
Share on other sites

 

 

Aaron....Geez, that thing does sound rowdy!  A Fire Dept. piece, am I right?  Thanks for the link.  I like.

 

Yep, an old Crown. The AMT / Ertl American La France kits include an 8v71, as do several of the semi-truck kits. 

The older Detroit Diesels (up through the 1990s) were two stroke engines which is what creates the different sound. Most diesels have been 4 stroke engines. Detroit Diesel and Cummins have been producing diesel engines in the US since the 1930s. While they were available for decades, and really started to become popular in trucks during the 1960s, diesels didn't become the dominant power plant for heavy trucks until the gas crisis of the 1970s.

Caterpillar offered diesel powered tractors as early as the 1930s. I don't believe they entered the truck market until the 1960s when they built some diesel engines for Fords C series trucks. These were really medium duty engines, I don't think they offered a real Class 8 sized diesel engine until the mid 1970s.

As KJ mentioned there were others that are no more or are at least out of the truck engine business, Buda was acquired by Allis Chalmers in the 1950s and then focused on agricultural tractor engines. Continental and Waukesha are still around but now mostly build stationary engines (for generators and such). Hercules exists now as a parts supplier supporting the engines the company once built. 

 

One of the things that we have a shortage of in model truck kits is the older gasoline heavy truck engines from Hall Scott, and Continental along with a few others. These were large to huge gas engines, Continental sold inline and V engines from 427 (7 liter) to 820 cubic inches (13.4 liter), Hall Scott offered one of the largest a 1091 cubic inch (17.9 liter) inline 6. You can find the Hall Scotts in a lot of west coast Kenworths and Peterbilts as well as fire apparatus well into the 1960s. Hall Scott also made a huge V-12 2269 cubic inch (37.2 liter) marine engine that supposedly found its way into some Kenworth trucks (900 horsepower at a time 300 hp was a lot of power). 

Edited by Aaronw
Link to comment
Share on other sites

Hey Michael,

Fishing for Gearheads, throwing bait like that in the water.

K.J. is right. Rudolph Diesel, in the mid 1890s, worked on using the inherent heat from compressing air, to ignite a fuel. After a few experiments, one explosion that almost killed him, he found a by-product of the crude oil refining process. It was cheap, plentiful, and at the time burned off as waste. He found that by atomizing, and injecting this waxy fluid into a piston compressed cylinder, as the piston neared Top Dead Center, the fuel would combust, and the engine would sustain itself, without external ignition source.

Clessie Cummins work on 4 stroke engines, in the 1930s, and turbochargers, in the 1950s, were huge coffin nails for the 2 stroke Detroits. He used the Indy 500 as his final test bed, having been on the Marmon pit crew for the first 500 in 1911, setting speed records, endurance records through the 1950s, all with diesels.

California hot rodder Clayton, speaks the truth. Hot rodders, after WWII, started pulling the superchargers off of diesels and adapting then to automotive gas burners. Even today, the size designations of Roots type, (GMC), blowers. 4-71, 6-,8-,10-, 12-, 14-71 all owe the name to the old Detroit engine displacements. The size of the supercharger was determined by case and rotor size needed to fill the given number of cylinders, 6, 8, 12, etc with 71 cubic inches of air per crank rotation.

Incidentally, the 2 stroke Detroit engines require air to be forced into them by the 'blower', in order to run at all. Being a 2 stroke design, with the intake ports in the cylinder walls themselves, they do not have a separate intake stroke, like 4 stroke, gas and diesel engines use to draw in their own air.

The most prevalent configuration, today, is the inline 6 cylinder. Early on, Cummins found out that inline engines generate more torque per cubic inch than VEE configuration engines. With a couple of notable exceptions, the V903 Cummins, and the 3408  Caterpillar, the majority of successful Truck engines are 6 poppers. The first, production engine to make 600 horsepower, was a Cummins KTA-600, a 6 cylinder. A benchmark not even the venerable 12V-71 could make.

As I try to get my inner Diesel Geek under Control, don't forget, even ALLIS - CHALMERS tried to get into the truck engine market, in the 1970s. "Big Al", as it was marketed as, looked good on paper, and even painted purple metallic, but in reality had severe crank longevity issues that made it just another also ran.

Now, consider all the different developmental series for each mark. The Detroit V-71s, V-92s, V-92 Silver, Series 60, DD 14 and DD15 versions. Cat,s 1693, 3406A, B, C, 3406E, 3408, C-15, C-16. Cummins' NTC series, KTAs, 855 series, ISX, Signature 600, just name a few.

OK, I'll stop now.

 

 

 

Edited by purepmd
spelling correction
Link to comment
Share on other sites

It makes you wonder, that, if in the name of weight savings, the engineers are using theory and not practical evidence when it comes to designing the reinforcement of the main journals and caps. Maybe even in the crank itself. For the lack of a few pounds of well placed cast iron and steel, you get ridiculous failure rates. I would almost bet real money, the thrust bearing main journal is flexing and or cap is walking during clutch disengagement and under high load situations. That is one thing to be said for the heavy 3406 family. The bottom ends of those engines were almost bullet proof, as long as you keep fresh oil in it like you were supposed to. Cat had more million mile, in-frame free engines than anyone else. I am sure a lot of mechanics as well as drivers miss the yellow motors under the hoods. Just my 2 cents worth.

Happy Thanksgiving Everyone.

Edited by purepmd
Added information.
Link to comment
Share on other sites

Mark, i couldnt agree with you more on the 3406. I am an old school Detroit fan ( mainly for the sound!) But a 3406 is a tough and powerful engine. I'm a diesel mechanic for the company i work for, but i also drive for them...best of both worlds! We have a t800 with a 3406 thats getting ready to turn 2 million! It can still walk the dog too. From a stand still, it can hang with the best of em! Drove back home 300 miles from the WV mountains with a busted #1injector line, loaded @ 65 mph, no problem! The 359 in the pic has a 3406 as well.

Link to comment
Share on other sites

Oddly enough the allis chalmers big al was the buda 844 with newer injection and turbo tech. And the paccar engine is of DAF design. DAF being a DUTCH truck manufacturer owned by paccar.The maxforce13 was a joint design between navistar and MAN a austrian truck builder. The maxforce 15 found in moebius kits is a c15 cat with navistar injection and emissions. By the way cat had 2 engines they tried in trucks in the 40s with no success but reentered the truck market in 1962 with the 235 hp 1673 installed by a cat dealer in new ih emeryvilles for denver chicago trucking..Popularity wise Cummins held the crown till the late 80s when the series 60 detroit came out. As far as million mile untouched engines go I would give that to the n14 cummins based on the fact there were far more n14s than 3406s built both were great engines and better than anything made today.

Link to comment
Share on other sites

Mark, gone fishing now!  What a good read, thanks for posting.   A million miles....insane quality.  I had no idea.  Also Clayton mentioning stopping and idling in the city and not using the clutch.  All new to me.  Again, I'm enjoying the exchanges and the info here.

The Paccar engines, they're Peterbilt, am I right?  I think I read about these on recent travels.  Something too about CGI blocks too, was this with Paccar, I don't recall.  Maybe that's a problem too concerning longevity instead of heavy old iron.

Leo, thanks for your input.  I'm going to do some searching this time Cummins in on the agenda.

Happy Thanksgiving guys.

Michael

 

Link to comment
Share on other sites

Mark...

I sure do! I would much rather have a 3406 or C12 or a C15 than this ungodly heavy DD15 I'm drivin now. It pulls well. But, I think it's a problem when a truck, that's empty, the steers weigh 11300. To me, that's a big problem, especially when a company gets paid by the weight. Some reason the company looks at me cross eyed when I say something about it. But what do I know, I'm just a truck driver.

Edited by Petetrucker07
Link to comment
Share on other sites

Micheal. PACCAR is KW and Peterbilt here. I had a truckin bud tell me, PACCAR or no car. Since the new trend now is callin big trucks, Large Cars. I will Never use that term, large car, to describe a truck. Well, unless it's I'm talking about a Volvo. But, I'm sure that will stir the pot a bit.

I just want to say, THANKS, to everyone commenting on Micheal questions. We all have kept it civil and adult. It's almost hard to believe there wasnt any pissin matches in any of his question threads.

Happy Thanksgiving to all!

Edited by Petetrucker07
Link to comment
Share on other sites

Hey Clayton,

Yep, it's been nice and easy going.  But now I'm thinkin' maybe I ought to get out while the gettin's good. lol.  I won't get rowdy with a bunch of truckers, no way.

Hope you guys have a good long weekend too.

Link to comment
Share on other sites

Hey Leo,

I did not figure the shear numbers of the N14, and N14Plus engines. Cat's win would have to be based on PERCENTAGE with N14s outnumbering 3406s  The N14 is not a bad engine. I have seen several with over 800,000 miles, well on their way to 1 million miles without anything but regular maintenance and an overhead. Even driven a 525 horse N14 Plus, and it was pretty grumpy. It would give a buddy of mine's 550 3406E a scare once in a while.

Edited by purepmd
added more
Link to comment
Share on other sites

I would say between a 3406 and n14 it boils down to personal preference over all. I've seen both do a million plus miles with  nothing but simple maintainence. The 3406 n14 and 12.7 series 60 pre egr were the best engines ever made hands down. The c15 isx and dd 15 would probably be just as good if they weren't so over loaded with emissions equipment. Certainaly enjoyed this thread 10 thumbs.

Link to comment
Share on other sites

Leo, so the end of the Cat 3406 was emissions control?  Heck, with today's VW emissions scandal, why not hook up some VW software to those babies and fire 'em back up!

@guitarsam....Sam, as a mechanic, what makes a good Diesel live so long?  Constant low rpm's.  I guess the internals, crank rods and pistons are all forged.  If the Diesel needs high compression to fire, I suppose the motors have a real tight quench.  But the way some sound while idling, it seems like the rods are just knocking around all over the wrist pins and something else banging against the block to make such a racket.

In short, how can a good Diesel live so long?

Plus, how many years does it take to drive a million miles?

Michael

Link to comment
Share on other sites

Michael, I know you asked this of a true mechanic, and I certainly will defer to an expert opinion, so if I am wrong, he will certainly correct me. But summations are, indeed, correct. Most engines are governed at 2100 RPM, so the detrimental harmonics of high crank speeds are not much of an issue. Very strong internal components definitely add to the lifespan. Precision machining does not hurt a thing. Highly efficient and well designed oiling systems, and massive amounts of well filtered oil is essential. Most six cylinders hold 10 to 12 gallons, depending upon oil cooler and filter configuration. Large, conditioned, and filtered cooling capacities try to keep heat, man other engine killer at bay. It helps to have a driver with a equipment minded head on his, or her shoulders. For example, long grades and high air temperatures, the Mojave Desert out of Havasu Cityin August comes to mind, should be enough for you to ease of the throttle a few hundrred RPM, shut the air condition off, roll the windows down and turn the heater on if needed. Making sure the routine maintenance gets done, not driving with your right foot glued to the floor board, and respecting the machines limitations all figure in from the drivers perspective. Mechanics and owners that really want to keep tabs on an engines condition, can send samples of the used oil to be analyzed as to what and how many microscopic metal particle are in it.  You can get an idea of the condition of the rings and bearings, especially, by seeing if the oil is high in the metals the these are made from. Copper, steel, iron, etc, will all show in the analysis. At what level is one of the concerns.

Another trait that helps them live long lives, is their very design. A large bore, combine with a very long stroke, generate massive amounts of torque. Torque is, arguably, the true measure of an engine. Horsepower sounds all flowery, torque is the force generated by the rotation of the crank that makes all this possible. 1600 to 1800 lbft is to be expected from 14 liter and up engines. And being able to develope this at such relatively low engine speed helps to.

If 1 single aspect can be put forth as the most import as to long life, it is maintaining the power plant at least to factory recommendation. That is true of any engine, the outboard Mercury on a Bass boat, to the Brigg & Stratton lawn mower, to a Cat in a OTR rig. The harder you work it, the better you maintain it.

As one who had a driving career span several decades, driving 1 million miles is different from driver to driver. My first year out, I turned just over 100,000 miles. That was by far my worst year. Rookie level for sure. My best year I rolled over 175,000 miles, all solo. Forget sleep and home time. Teams can run, upwards of 300,000 miles in a year, if they are dedicated to making money, not hanging out in truck stops. I drove over the road for 16 years, and racked up just over 2,000,000 miles. That is an average of 125,000 a year, some really good some, not so much. Figure in the time I spent doing route driving, and local hauling, mostly sand and gravel with a belly dump trailer, and I guess I have over 2.5 million miles of windshield time.

Edited by purepmd
Link to comment
Share on other sites

Your first question Micheal... D.O.T. has an outside emissions company set up at "random" scale house to check "random" trucks exhaust. Here southern California, they are almost done building a super coop, on south highway 15 just inside the Nevada - California stateline. It's setup to check everything coming into Ca, trucks and reefer trailers for emissions. So just putting a "mask" on the computer isn't really viable.

For your second question. Diesel engines are designed and manufactured with best materials and parts. Tolerances are tighter, forged rotating assemblies, and are purpose built to run under the harshest conditions. 

Here's a little bit of info you may not know. The injector pressures are very high, very high. Around 25000 to 40000 psi. There is an 8 credible amount of fuel injected into each cylinder. The Cummins ISX, has up to 625 horses and 2050 pound feet of torque, from factory! There are performance companies that can double, almost triple that and, if driven properly, can still be just as reliable. 

The knocking you hear is piston slap, lifter chatter and some cylinder knocking. The piston slap, It occurs because the fuel combust before top dead center. It combusts once the cylinder pressure is high enough. Diesels are designed for the slap. The motor will get noisier as it gets higher up in the mileage. On old small and big cam Cummins, the air compressor makes a lot racket also. The fan clutch on 3406s make a lot knocking noises too.

And lastly... during a normal year of driving, we drive around 12500 miles a year. So it takes between 7 and 10 years to get to a million miles.

Link to comment
Share on other sites

Oh, I almost forgot, most of the noise you hear at idle, is the explosion of the fuel combusting. The same effect can be heard in gasoline engines not timed correctly. The rattle of detonation in a gas burner, is normal combustion in a diesel. Clayton is right, again. Piston slap, the piston rocking side to side on the wrist pin, is normal. Especially loud on cold starts. The clearances in such a large bore have to be so large, that piston slap is the norm. Heat and radical increases in cylinder pressure miniseries it. A trained ear can determine manufacturer by the sounds at idle. They don't call them Clatterpillars for nothing.

 

In closing, I know finally, right, a little, useless factoid. The distance around the equator of this planet is just under 25,000 miles. That means one would have to drive more than 100 times around the world to equal the miles I racked up in trucks. I apologize if that seems like bragging, but, like my Grandfather used to say, "It ain't braggin if you can do it.", or in this case have done it.

This has been a very enjoyable topic.

Edited by purepmd
More info.
Link to comment
Share on other sites

Mark, i dont disagree with you a bit. Maintenance is the #1 most important thing for a diesel....well that and NEVER using ether! Driver error is the #1 killer of a diesel engine and the rest of the truck for that matter. I did an inframe on a c13 last year at 246,xxx miles due mostly to driver error. He thought he could just drive the truck LOADED 50 or so miles back to the shop.....with nothing in the radiator! Busted head was the result. I had a different driver just recently inform me that he had been adding plain water to the radiator for the past 2 months, mind you i am a fleet mechanic. These guys come by the shop every morning and all they have to do is pick up some antifreeze. To ad insult to injury, we carry prediluted coolant! Electrolysis is a big killer of diesels. It pretty much vibrates holes into cylinder walls. Well thats my spill for now. Really great topic, i love talking gears with other gear heads!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...