Cummins V-8 and V-6

[Joe G.]

I don't agree with larger tolerances making an engine last longer than one with tighter tolerances. I don't think that makes any sense at all.

 

[ezcurra]

I think you may be confusing tolerances with clearances.

I don't agree with larger tolerances making an engine last longer than one with tighter tolerances. I don't think that makes any sense at all.

 

[Joe G.]

I agree with Ryan (rbattelle) about what tolerances are. I don't agree with him that looser tolerances will make an engine more tolerant to environmental changes or wear. Looser clearances will make an engine faster but it will not last as long. Look at race engines for example.

 

[hammersley]

OK - this just confirms my thoughts - this is my last truck?

I plan on repairing this one forever - afterall if new were more economical all you would ever see would be new taxi cabs! And how old are those B 52's and the Constellations (P-3's)????? Alwasy always cheaper to repair than rebuild unless you have some tax scam - I mean - deduction... ...

 

[ezcurra]

Imagine a crank journal in the high side of the (very wide) tolerance range, diameter wise, and a bearing on the low side of another very loose tolerances. The clearance will be very tight, and most likely the engine won't last very long. Tight tolerances allow parts to be repeatable and to prevent nasty tolerance stack ups from happening.

 

[RSeverance]

I guess I will mention that the Bradley Fighting Machine has a Cummins 905 V-8 We recently rebuilt one here in our shop. Pretty cool little package. These engines are designed to be a swing in replacement in the battlefield. Once they swing an engine to old goes out to be rebuilt after so many hours.

 

[rbattelle]

I agree with Ryan (rbattelle) about what tolerances are. I don't agree with him that looser tolerances will make an engine more tolerant to environmental changes or wear. Looser clearances will make an engine faster but it will not last as long. Look at race engines for example.

Race engines are usually of very tight tolerances and are built with very high precision parts. And they are usually replaced or rebuilt after every race (I'm talking NASCAR, F1, Dragsters). I think that speaks volumes.



Joe, maybe I'm totally off-base. These are just opinions I've formed from what I've seen and reasoned out. I respect your opinions on this matter.



-Ryan

 

[Joe G.]

You are certainly right about the tolerances for a race engine. The guys that are professional builders of those things require that the parts are exactly on spec as far as possible. The clearances, however, can be really loose to minimize friction. That was one big difference between a qualifying engine in NASCAR and a race engine before they made them race with the same engine they qualified with. A qualifying engine would never have made it for 500 miles. If we ran an on road engine with those clearances it wouldn't get very far before we had to overhaul. No chance of getting 100K on one of those. That is not counting the special parts for racing. Take a look at a race engine piston and a street piston sometime. Tight tolerances don't shorten the life of a race engine. Special parts and very loose clearances do. When I used to mess around with hot rods in the '50s we would build a flathead Ford with really loose clearances. It didn't last long, but it hauled butt until it died.

 

[TSterken]

First John Deere only go's up to a 13. 5L and is pounding out 550hrs but it can do so much more. I believe that the most powerful tractor. And if you want to talk about MFWD the 8520 with ILS walk all over every one. This year at the county fair farmer's pull the IH and also Deere's without ILS had about 3/4 pulls ante the 8520 ILS went all the way down the track and started to clib the rock pile at the end of the track befor e that shut him down. The cummins is the only thing IH has going for them. So the n14 is bigger but my money is and alway wil be on a john deere diesel engine. Don't get me wronge, cummins make' a nice engine. There are some things I don't like about them to. (dry sleves) But dodge is the only truck that has an inline 6 engine and thats why I got a dodge. If Ford put in John Deere's 6. 8LPowerTech in there truck. Proude Dodge and Cummins owner would have a new Deere power Ford Superduty. (expesselly if dodge stops putting the 5. 9L and pust the V-8 in diesel)

 

[rbattelle]

You are certainly right about the tolerances for a race engine. The guys that are professional builders of those things require that the parts are exactly on spec as far as possible. The clearances, however, can be really loose to minimize friction. That was one big difference between a qualifying engine in NASCAR and a race engine before they made them race with the same engine they qualified with. A qualifying engine would never have made it for 500 miles. If we ran an on road engine with those clearances it wouldn't get very far before we had to overhaul. No chance of getting 100K on one of those. That is not counting the special parts for racing. Take a look at a race engine piston and a street piston sometime. Tight tolerances don't shorten the life of a race engine. Special parts and very loose clearances do. When I used to mess around with hot rods in the '50s we would build a flathead Ford with really loose clearances. It didn't last long, but it hauled butt until it died.

I agree with everything you say here. I think we're talking about the same thing but confusing the terminology, perhaps.



-Ryan

 

[Vaughn MacKenzie]

Here is the latest article on the V6 & V8 development, Sept 2004. The last one I saw was from 2001. http://www.orau.gov/deer/presentati... Light Truck Progress SECOND PRESENTATION.pdf

 

[datablitz]

thought i would just throw something out about the JD conersation and say that the smaller jD tractors do not have JD motors, but its a yamar or something... i believe they only use "JD" motors in thier bigger series, starting at around 50hp

 

[ndurbin]

Yeah the smaller ones are powered by Yanmar diesels. 4010 series and down. 4020 series and up use JD engines starting at 43hp. The Yanmar diesels are N/A and the JD engines are turbocharged.



Nathan

 

[dodge cummins]

what is the point of a higher revving diesel.

 

[RustyJC]

what is the point of a higher revving diesel.

If the torque curve is pretty flat, more BHP for a given amount of torque. Think in terms of the V-10 turbodiesel in the VW Touareg, the BMW diesels available in Europe, etc. Although perhaps not what those of us who tow heavy loads are seeking, the high-revving V-type diesels exhibit operational characteristics much closer to gasoline engines and are, therefore, more accepted by the broad "automotive" consumer marketplace.



Rusty

 

[amsoilman]

Here is the latest article on the V6 & V8 development, Sept 2004. The last one I saw was from 2001. http://www.orau.gov/deer/presentati... Light Truck Progress SECOND PRESENTATION.pdf

Just received the January edition of "Four Wheeler" MAG, and there was an article regarding the V-6 and V-8 Cummins Diesels. (written by Greg Whale) These are prototype engines, and are designed for under 8,500 CVWR applications. The V-8 5. 6L engine weighs 766 lbs. and is rated at 300 HP@ 3,800-4,000 rpm and 460 lb-ft @ 1700-2,200 rpm. The V-6 is rated at 250-270 HP with the saame torque. The article went on to say the noise level with the hood open is lower than the current Ford Powerstroke with its hood closed! The article also mentioned the "Ram cranked off runs of 0-60 mph in under 9 seconds while averaging a claimed 22 mpg!



DON'T EXPECT TO SEE EITHER OF THESE ENGINES UNTIL MODEL YEAR 2009!





Wayne

amsoilman

 

[Gary - K7GLD]

We can kick around the expected advantages of V-configuration engines 'til the cows come home - and there ARE some advantages - but how do they compare overall with the traditional characteristics that created "diesel appeal" to begin with?



Traditionally, inline diesels delivered extreme low RPM grunt, extreme engine life, extreme fuel economy, and simplicity of design that allowed virtually DECADES of trouble-free life in agricultural situations where they were worked HARD!



How many of those targets will the newer V-configuration engines hit?



OR, if the newer V-configuration diesels are what their supporters would like us to think they are, how soon can we expect to see them in abundant use in the 18-wheelers?



Sure, technological and operational advances WILL be incorporated in newer V-configuration engines - but those SAME advances for the most part could ALSO be incorporated into the inline engines, if that was really an advantage in regards to above listed values long standing in diesel circles...



As compared with inline diesel engines, how many million mile plus V-configurations are there out on the road?



IF a buyer is PRIMARILY interested in slightly greater accelleration, and a more "car-like" operating diesel, where hard work and heavy towing ability is NOT an issue, then the V-configuration may be fine. But for a hard working TRUCK, give ME a long stroke inline engine every time!

 

[RustyJC]

IF a buyer is PRIMARILY interested in slightly greater accelleration, and a more "car-like" operating diesel, where hard work and heavy towing ability is NOT an issue, then the V-configuration may be fine. But for a hard working TRUCK, give ME a long stroke inline engine every time!

Gary,



With all respect, I believe that's what I said.

Although perhaps not what those of us who tow heavy loads are seeking, the high-revving V-type diesels exhibit operational characteristics much closer to gasoline engines and are, therefore, more accepted by the broad "automotive" consumer marketplace.

Rusty

 

[Gary - K7GLD]

"With all respect, I believe that's what I said. "



YUP - but what *I* was attempting, was to place greater emphasis on what I and some others consider the SHORTCOMINGS of the impending switch to higher reving V-configuration engines - as well as the possible detrimental effects of increasing operation RPM of inline engines - there is likely a price to be paid - and that price may well be in several areas many of us value for our specific use.



It was beginning to look as though some here felt the switch to "bent" engines was all a grand and positive thing - I don't think so! No, not even if *Cummins* is forced into it by environmentalists or other outside forces - the notion that "if Cummins does it, it will be great" vastly overstates reality - after all, GM made "diesel" engines out of beefed up Chevy smallblock engines - Ford marketed the Edsel - and Gm floored the Corvair...



Just because a usually successful major player is involved doesn't assure success or a wise new direction from the consumer point of view...

 

[amsoilman]

"With all respect, I believe that's what I said. "



YUP - but what *I* was attempting, was to place greater emphasis on what I and some others consider the SHORTCOMINGS of the impending switch to higher reving V-configuration engines - as well as the possible detrimental effects of increasing operation RPM of inline engines - there is likely a price to be paid - and that price may well be in several areas many of us value for our specific use.



It was beginning to look as though some here felt the switch to "bent" engines was all a grand and positive thing - I don't think so! No, not even if *Cummins* is forced into it by environmentalists or other outside forces - the notion that "if Cummins does it, it will be great" vastly overstates reality - after all, GM made "diesel" engines out of beefed up Chevy smallblock engines - Ford marketed the Edsel - and Gm floored the Corvair...



Just because a usually successful major player is involved doesn't assure success or a wise new direction from the consumer point of view...

Here's another intersting piece of informtion on the Cummins V-6 & V-8 Diesel. It uses aluminum heads/Iron block! Looks like they took a page from GM/Isuzu!



Wayne

amsoilman