WW2 Iron

[Birken Vogt]

I think the problem was related to the rings crossing the intake ports and chopping the longer oil viscosity improver molecules up.

As for the powerband, it was not due to any intake/exhaust tuning but the simple fact that the standard no-extra-cost fuel injection system was only a min-max governor. No torque rise at all. It simply injected x amount of fuel per stroke no matter what the RPM. Therefore the way to get up the hill fastest was to run at the highest RPM so that you had the most fuel injection events per minute.

Some DD engines had tailored torque, that was an extra option governor with more advance fuel control so that it behaved more like a Cummins to the way I understand it, but I never saw one, however I did drive a DDEC version and it also had good torque rise down to 1400 RPM, not necessary to rev that one out at all.

 

[td25c]

I have a few old military manuals from the 1950s. They state that no oil is ever too thin. The harm of too thin an oil is rapid consumption.
While an engine has multiple points needing lubrication, it may not get everywhere it is needed if pressure, and volume aren't adequate. Stiff oil might not make it to all the remote places, light oil will. If there is foreign matter somewhere, light oil will flush it to the filter, thick oil won't. I use 10W-30 except for very hot summer weather

Probably something to that in cold weather ....... Better off to have good flow of lube going everywhere in the engine and an easy crank in sub zero temps .

 

[td25c]

Oh Yeah ...... Detroit diesels .......

Drive them like a small block Chevy & put something slick in the crankcase .

The fellers that built the Detroit diesel also built the small block chevy .....

They aint temperamental engines as many would think ....

 

[RZucker]

I think the problem was related to the rings crossing the intake ports and chopping the longer oil viscosity improver molecules up.

As for the powerband, it was not due to any intake/exhaust tuning but the simple fact that the standard no-extra-cost fuel injection system was only a min-max governor. No torque rise at all. It simply injected x amount of fuel per stroke no matter what the RPM. Therefore the way to get up the hill fastest was to run at the highest RPM so that you had the most fuel injection events per minute.

Some DD engines had tailored torque, that was an extra option governor with more advance fuel control so that it behaved more like a Cummins to the way I understand it, but I never saw one, however I did drive a DDEC version and it also had good torque rise down to 1400 RPM, not necessary to rev that one out at all.

The rings crossing the air ports, that's it. Now I remember that.
Tailor Torque was used on the 8V-92 "Fuel squeezer" engines. PITA to set, it used 2 Belleville washers on the governor capsule that would compress when the engine was lugged, 1300 rpm was the low point before a downshift or it didn't work right, a 9 spd seemed to be the best transmission choice with them. They used huge injectors to gain that low end torque at low rpms.
Detroit called it "constant horsepower" with dropping rpm. I do know if you replaced the governor capsule with a standard limiting speed type, that "Fuel squeezer" turned into a 500HP "Fuel eater"[/QUOTE]

 

[RZucker]

Oh Yeah ...... Detroit diesels .......

Drive them like a small block Chevy & put something slick in the crankcase .

The fellers that built the Detroit diesel also built the small block chevy .....

They aint temperamental engines as many would think ....

I've seen way too many running 71s that would be classed as 3 legged dogs still doing their jobs every day. I really doubt there is a tougher engine out there.

 

[td25c]

I've seen way too many running 71s that would be classed as 3 legged dogs still doing their jobs every day. I really doubt there is a tougher engine out there.

It's a hard call RZ ....

71 series Detroit up against a small block chevy ....... Two awesome engines !

Small block Chevy cheating using a 6 - 71 blower on top . LOL !

 

[ol'stonebreaker]

Since I'm now an old timer I'll say the old timers told me when a Detroit quit leaking oil it was about to blow.
Mike

 

[RZucker]

It's a hard call RZ ....

71 series Detroit up against a small block chevy ....... Two awesome engines !

Small block Chevy cheating using a 6 - 71 blower on top . LOL !

Small block Chevy's didn't have air box drains...

 

[Birken Vogt]

My impression was that in those days the 2 cycle Detroit was the low cost "base option" if you will and if you wanted to be cool you bought a Cummins or Cat instead. Correct me if I'm wrong. They were already starting to get old when I started. We were not so nostalgic about them then as we are now.

 

[DMiller]

I remember the 'Shear' notations when going to DD Schools in the 80's, the 92s were allowed the multi weight oils but they almost forbid them in the 71 and 53 series, every 110 I worked on only got 40wt straight wt.
Oil rings on the DDs were at the base of the skirt below the wrist pins with three compression rings above and loaded tin seals on the wrist pin bosses for air box sealing. If memory serves(hasn't much lately of note!) the use of multi weight oils allowed infiltration of the lube into the air box thus into the combustion chambers leading to higher consumption, not certain why the 92's were less apt to do that.

As such the old DDs were seriously NASTY about carbon deposit in the oil, that stuff would stain a black t-shirt, Mack was almost as bad.

 

[Truck Shop]

As I have said on here before George Romminger an old trucker that ran nothing but Detroit's in his trucks never changed oil just the filters. He would get
800,000 out of an engine. The inside of one was like ink. And he ran nothing but 30 or 40 wt.

Truck Shop

 

[hillbillywrench]

There’s a local truck that gets fired up a couple times a summer. Jimmy with a 318? DD. It’s the last thing pulled at the local truck/tractor pulls. It has a propane line plumbed into the intake for a little more “juice” and the governor has been “adjusted”. It makes a good Grand Finale! My daughter likes to see it pull so I get to stay for the whole show without having to listen to any “daddy, can we leave early?” questions.
The guy that owns it has an Ag salvage yard. A buddy of mine went there to look for some parts one day. He took his grandsons with him. He was in the office trying to locate parts and realized his grandkids were missing. The owner had taken them out in the back lot, fired up an ancient D9, and was taking them for a ride (over some junk cars). They sure were having FUN crushing cars. Too bad it wasn’t a Euclid with twin 6-71’s!
Put a hillbilly in a junkyard and watch the fun!

 

[RZucker]

As I have said on here before George Romminger an old trucker that ran nothing but Detroit's in his trucks never changed oil just the filters. He would get
800,000 out of an engine. The inside of one was like ink. And he ran nothing but 30 or 40 wt.
I just worked over an ex Ulmer truck from E-burg. 3406B, just as nasty black inside. The poor thing saw so many acid washes you just cut bolts to take stuff apart

Truck Shop

As I have said on here before George Romminger an old trucker that ran nothing but Detroit's in his trucks never changed oil just the filters. He would get
800,000 out of an engine. The inside of one was like ink. And he ran nothing but 30 or 40 wt.

Truck Shop

George wasn't the only one doing that. In the early 80's PNW Bell (phone company) was doing the same with their gasoline fleet and still getting good engine life. I think Consolidated Freightlines was doing the same with their 6V92s near the end.

 

[Truck Shop]

I think Consolidated was doing that out of desperation. Just like Parker Refrigerated Truck Lines near the end.

Truck Shop

 

[RZucker]

I think Consolidated was doing that out of desperation. Just like Parker Refrigerated Truck Lines near the end.

Truck Shop

You may be right. But I did hear that story from a DD rep in the early 80s.

 

[hillbillywrench]

I had a neighbor one time that would get waste oil when his buddies changed their oil and that’s what he poured in his pickup. He never changed the oil, just added some every day. Never changed the filter either. Then complained cause he had to do engine swaps all the time! LOL.

 

[RZucker]

I remember the 'Shear' notations when going to DD Schools in the 80's, the 92s were allowed the multi weight oils but they almost forbid them in the 71 and 53 series, every 110 I worked on only got 40wt straight wt.
Oil rings on the DDs were at the base of the skirt below the wrist pins with three compression rings above and loaded tin seals on the wrist pin bosses for air box sealing. If memory serves(hasn't much lately of note!) the use of multi weight oils allowed infiltration of the lube into the air box thus into the combustion chambers leading to higher consumption, not certain why the 92's were less apt to do that.

As such the old DDs were seriously NASTY about carbon deposit in the oil, that stuff would stain a black t-shirt, Mack was almost as bad.

I think you pretty much nailed it on the oil consumption issue. I don't remember multi vis being permitted in 92's, I always gave them the same treatment as the other 2 strokes. Maybe the oil rings were redesigned? I do know that after installing rings on 53's and 71's my fingertips were just shredded. 92's didn't seem to do that.

 

[DMiller]

Ain't that the truth on the rings, sharp like razors on the ends. 71s had multi-piece oil control rings, didn't the 92s go with one large cast iron twin lip and a spring tensioner? Or am I thinking backwards, 71s having the big iron ring?

 

[Willie B]

My son met a man 8 years ago. He was deeply impressed that this man ran an under powered antique tractor competing formidably in antique tractor pull competitions. When I met this man, I learned that over 60 years, we had been in the same place at the same time hundreds of times, but never met.

A couple years ago he said he'd bought a tractor. It is an oliver with Detroit Diesel. These tractors are stock. They get modified with injectors, pistons, cam shafts, and, if originally equipped with blowers, bigger blowers. He went from mild mannered, get all you can before tires slip, to madman on a Detroit. These days it's front wheels in the air, black smoke scarry! Tractor pulls are down to 1 of three regulars will win. Dave has had some hip problems. This year his hip is fixed. I expect the winner to be more predictable.

Willie

 

[RZucker]

Ain't that the truth on the rings, sharp like razors on the ends. 71s had multi-piece oil control rings, didn't the 92s go with one large cast iron twin lip and a spring tensioner? Or am I thinking backwards, 71s having the big iron ring?

Nope, 71's used 2 oil rings. one chrome and one black, I don't remember which order they went in. Been a while but I think you're right about the 92 oil ring.