Fuel usage: "new" vs "old" diesel engines

Irish Rambler · Apr 17, 2022

Art we already know that, but the oil companies and the more importantly the executives who drive them are making too many $$$$$$$ to change their ways. Maybe the Russian Ukraine invasion may make them wake up.

Slowgoesit. The problem with the new engines is that they are a pony trying to do a horses job and they can't stick the pace as long as the real McCoy.
Just to hear the unique sound of the starter kicking over the big gal makes my heart sing, my tool box takes the huff and snaps shut because its not needed !
I'm envious of you. Enjoy the best of British engineering.
Its ironic, when the first Swedish Volvo's and Scania's came on the scene they were revving out at up to 3,500 with a 16 speed box, and now ? They have all gone back to the high torque slow revving 1950 rpm with 8 speed boxes.
That's progress ? ?

Simi 60 · Apr 17, 2022

Irish Rambler said:
Slowgoesit I owned probably 15 trucks with Gardner engines in the 60's 70's and providing you serviced them correctly they were virtually indestructible. .

My grandfather did his apprenticeship in England working on Gardner powered double decker buses then later, drive them .
Have a copy of his apprenticeship papers on a hard drive somewhere.

I don't remember stories about the motors but do remember one about the driving test where the instructor made him stop on a hill and then took out his ornate fob watch and placed it under the back wheel.
He passed the test.

dannc · Apr 18, 2022

slowgoesit said:
We're pretty tickled with it! People are often taken aback by just the SIZE of the beast though!

On a visit to a boat builder in China, there were two 8XLBs sitting on pallets under tarps waiting to be installed in a commercial inland water way ship that was being refurbished. The engines were huge, yet beautiful and a work of art. Can't really say that for modern engines I have seen.

Later,
Dan

Hippocampus · Apr 23, 2022

Friend collects steam and very early oil powered farm equipment. Mobile and stationary. Brass, some bronze and even the iron is engraved in places. Wheels of most are solid and taller than I could ever dunk. All of his stuff still works. Most well over a century old. Stuff from 1922 is modern to him and rarely worth collecting.
Yes a different era. Gearheads are disappearing. Still glad Lucas prince of darkness is a memory.

Irish Rambler · Apr 23, 2022

Hippocampus. I remember as a youngster having to start the horizontal diesel, it had a darned great flywheels each side and you started it by opening the decompressor (no handles),turning the flywheel until you got enough speed up, then you shut the decompressor and she fired. She drove an overhead system of pulleys for different machinery.
Slowgoesit, we're searching through old paper invoices to see if we can find the part number for the modified water pump for your Gardner, I'll let you know if I find it.

mvweebles · Apr 23, 2022

Hippocampus said:
Still glad Lucas prince of darkness is a memory.

Q: Why do the Brits drink warm beer?
A: Because Lucas also made refrigerators.

I still own a 1963 Triumph Bonneville motorcycle I purchased in 1979. Not a memory.

Peter

socalrider · Apr 23, 2022

mvweebles said:
Q: Why do the Brits drink warm beer?
A: Because Lucas also made refrigerators.

I still own a 1963 Triumph Bonneville motorcycle I purchased in 1979. Not a memory.

Peter

Yeah being new to the diesel world it's funny how different the discussion is around old gassers. While there's still emotional attachment to the antiques nobody's asking questions about whether they're more or less reliable or fuel efficient! Having futzed around with motorcycle carburetors for hours and hours in sometimes dubious roadside or trailside locations I'm fine with EFI! Of course diesels always had fuel injection & no ignition so I understand mourning that lost simplicity & inherent reliability.

fgarriso · Apr 23, 2022

mvweebles said:
Can someone provide an objective citation that improved economy comes at the expense of efficiency? Because to my mind it's counter intuitive - efficient combustion of a hydrocarbon produces CO2 and H2O. Overall stats I could find show this is the exception, not the rule. But I couldn't find specific diesel (i could find trucks that show similar trend, though less pronounced). There could be a counter-current within the data, but without a citation, the macro data clearly suggests that efficiency follows reduced emissions which makes sense - extraction of more Btus makes more power and leaves less harmful byproduct (which is why I cited the California program to replace fish boat engines)

See below of what i could find. EPA comparison of actual emissions compared to efficiency. The counterintuitive trend - increased emissions and decreased efficiency- appears to be a 20-year anomaly from 1985-2005. Is it possible the anecdotal comments on this thread are dated?

So does anyone have any empirical citation (vs anecdotal) that diesel engines buck the overall trend that reduced emissions results in improved efficiency? Maybe diesels have a different trend, but hard to support that observation without data. I can tell you from experience that a Willard 40 with an old Perkins 6.354 (135hp) burns around 2.5gph at 7-1/4 kts whereas one with a JD4045T (120hp) burns closer to 1-3/4gph.

I'll say it again. There are several reasons to own an old mechanical engine. Fuel efficiency is not one of them.

Below is the referenced fleet average report, with a screen shot plucked showing correlation of three phases

https://www.epa.gov/automotive-trends/highlights-automotive-trends-report

Peter View attachment 127682

Peter,
The EPA reports you are referring to is for GAS engine's not HD diesels or class 7 or 8 trucks which have the engines we use in marine installations.
I don't claim to be an expert in diesels but I do know that marine diesels run more efficiently when loaded to 75-80%, but gas motors seem to be the opposite and are most efficient at 20-25% load.

Irish Rambler · Apr 24, 2022

Hi Peter,
Actually I'm Irish, I never liked the English beer or ales. The latest trend is for cold beer even in Ireland and Guinness was a far better drink at room temperature.
On the brief visits we make to the UK we see the younger Brits are also going more for chilled beer.

My first 'big' bike was a Triumph 650 which I modified with a Norton featherbed frame (Triton) which I raced on the South of England tracks. I was serving in the Brit army at the time and we got emergency posted to Cyprus during the terrorist campaign, some b,,,,,,,,d stole it whilst I was away on active service, it broke my heart to lose it like that. I never raced again.
Enjoy your Bonneville and give her a wee blip from me.

CharlieO. · Apr 24, 2022

Lookathat said:
Can I claim the prize for most efficient?
1966 Volvo Penta MD70, 6 litre diesel, 147HP, 8000 hours. 37' wooden ex commercial salmon troller.
1gallon per hour at 6 knots, 1300rpm.

Sure, but I'd be interested in more pics and info on your boat.

O C Diver · Apr 24, 2022

fgarriso said:
I don't claim to be an expert in diesels but I do know that marine diesels run more efficiently when loaded to 75-80%, but gas motors seem to be the opposite and are most efficient at 20-25% load.

Think you're confusing load with RPM. When running at peak torque, which is often around 75% of RPM, the engine is often most efficient. Increasing load and thus fuel consumption for the same RPM and air being sucked in, doesn't make combustion more efficient.

Ted

rslifkin · Apr 24, 2022

fgarriso said:
Peter,
The EPA reports you are referring to is for GAS engine's not HD diesels or class 7 or 8 trucks which have the engines we use in marine installations.
I don't claim to be an expert in diesels but I do know that marine diesels run more efficiently when loaded to 75-80%, but gas motors seem to be the opposite and are most efficient at 20-25% load.

In general, at any RPM, a gas efficient gets more efficient with increased load. Up to a point. As soon as you have to start richening up the fuel mixture to keep things alive (power enrichment), all bets are off. Depending on RPM and the engine in question, that'll usually happen somewhere between 50 and 80% load, at least for modern EFI stuff.

Diesels are non-throttled, so the efficiency curve is generally flatter than for a gas engine (although there will still be an optimum point).

Fuel usage: "new" vs "old" diesel engines

Irish Rambler

Guru

Simi 60

Guru

dannc

Guru

Hippocampus

Guru

Irish Rambler

Guru

mvweebles

Guru

socalrider

Guru

fgarriso

Guru

Irish Rambler

Guru

CharlieO.

Guru

O C Diver

Guru

rslifkin

Guru

Similar threads

Latest posts