Is a diesel engine really the best option?

Advice and help involving any mechanical issues.
User avatar
T1 Terry
Posts: 15962
Joined: Fri Nov 23, 2012 3:44 pm
Location: Mannum South Australia by the beautiful Murray River
Has thanked: 50 times
Been thanked: 30 times

Re: Is a diesel engine really the best option?

Post by T1 Terry »

Bow and NP, this is what I'm saying, these are truck motors, not the new gen ute motors, you simply couldn't fit one of those truck motors into modern ute. The vehicle's these motors fit in are called heavy vehicle, they require a different licence to drive, not the car licence for the modern diesel powered ute.
The biggest misconception is relating what a heavy vehicle diesel engine will achieve and thinking the toy diesels in the car type utes will do the same sort of heavy work for a million kms ...... they just won't because they are tying to extract big torque and HP out of an engine that's design base was for maybe 1/3rd of what they are extracting out of them these days.
Do you think the Cummins engines and 6BDT Isuzu used in a racing truck would give the million kms plus before needing a rebuild? That is about as close a comparison as I can give to what they are doing with the little ute diesel engines, they are race tuning them to extract the maximum power.
The CAT3208 is a great example, in the 210hp trim they last for ever just about, the 3208T is the same motor with a turbo and develops around 260hp to 320hp. Add an intercooler and multiple turbos, the same engine in a marine application can deliver 710hp, do you think they will deliver that sort of power for the same hrs as the standard 3208?
One of the passenger service busses we converted from 466 Bedford diesel to a 351 Cleveland with a 4 sp Alison clocked up 500,000kms before the company was taken over by another mob and the bus was sold off. The original 466 Bedford engine clocked up around 250,000kms but the fuel to oil ratio was even poor for a 2 stroke by the time it came off the road for a refit. This particular bus was bought up by the mob I bought to end of service life 500 Bedford diesel bus. They removed the 351 Cleveland and fitted an Isuzu 6BDT after one of the drivers manage to get a freeze burn when refueling the bus .... no idea how that could be done but that was their reason or pulling the still working 351 out.I asked the workshop foreman if the bus went as well with the turbo Isuzu as it went with the 351 on LPG .... his reply was they hadn't receive and speed infringements since the refit ...... For it's 1 million km celebration, the Isuzu through a leg out through the block, so the dropped another brand new crate motor and sent it back out to work.
The commuter bus engines in the smaller buses didn't ever get big miles before they needed a rebuild, it requires the long haul highway work to get the big mileage out of the older diesel engines. The newer wizz bang truck engines that develop big torque and power out of a much smaller capacity engine don't see the big kms either and when they do break they are a throw away item most times because the block and crank have stress fractures so not suitable for rebuilding. Many went back to the bigger capacity engines so they didn't have to work so hard and the longevity returned.

NP, the big mileage (well kilometer-age but it just doesn't roll off the tongue eh) on the Prius is because it was a Brisbane taxi in its previous life. I did put a timing chain and guides in it thinking that was the high rev engine noise, but that actually didn't need replacing and the noise was still there. Turned out to a blocked catalytic converter and the noise was the exhaust engine pipe compressing the mounting springs to release the exhaust pressure built up and then the pipe banging back against the exhaust manifold. Cost me $125 for an after market cat and as i bought the car for under $2000 in the first place because the taxi company owner thought the engine was stuffed, I reckon I did ok :lol:

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
Bow
Posts: 60
Joined: Tue Nov 15, 2016 8:26 am
Location: Harrington
Has thanked: 3 times
Been thanked: 4 times

Re: Is a diesel engine really the best option?

Post by Bow »

then they add EGR and DPF to help kill the motor .
native pepper
Posts: 1357
Joined: Mon Feb 23, 2015 8:21 am
Location: Tasmania
Has thanked: 5 times
Been thanked: 4 times

Re: Is a diesel engine really the best option?

Post by native pepper »

T1 Terry wrote: Mon Apr 12, 2021 2:27 pm
NP, the big mileage (well kilometer-age but it just doesn't roll off the tongue eh) on the Prius is because it was a Brisbane taxi in its previous life.
T1 Terry
The prius is a hybrid, so wouldn't have done that many klms on the petrol engine and as a urban taxi, most of it's klms would probably have been on electric. When the timing belt came off on my cruiser, the RACT taxi which took me and my dogs home (over 100klms) was driving a prius and he said they mostly use electric in the city because they don't have to keep starting and stopping the engine which costs them money. In my opinion, it's how you drive and treat your vehicle as to the distance it travels before it needs lots of work or a rebuild. Try to treat my vehicles like I treat my ladies, gently until they are warmed up, then after driving, let them cool down before shutting them down.
User avatar
T1 Terry
Posts: 15962
Joined: Fri Nov 23, 2012 3:44 pm
Location: Mannum South Australia by the beautiful Murray River
Has thanked: 50 times
Been thanked: 30 times

Re: Is a diesel engine really the best option?

Post by T1 Terry »

The Prius motor starts and stops by computer demand, not something you can just choose to do unless you make substantial modifications including adding an extended range battery. The standard Prius traction battery has a range from fully charged to cut out of about 5 kms at best, so a taxi wouldn't bother to try to drive mainly on electric, then have to stop a few kms later to switch back to hybrid (can't be done without switching the car off that immediately applies the park pawl in the gearbox and that's a real sudden stop)
No taxi would spens the $$ to add an extended range battery pack either, just to drive around the city at a max of 80km/h for between 50km and 80km before it had to be plugged in and recharged.
To climb a hill the ICE motor revs out at 4,500 to 5,000rpm for the high load part, then drops back to around 1800 to 2200rpm when the load reduces, or simply shuts down if under 80km/h if the load drops off enough for the 50kW of electric drive power is sufficient to maintain speed and there is enough stored energy in the traction battery ... and if it doesn't need to run the motor to heat the coolant for cabin heater duty.
Fairly hard on an ICE to go from 0RPM to 4,500rpm and then back to 0rpm frequently, but the Prius ICE does it and judging by the high kms on the odometer, it does it without too much wear and tear. I can't imagine a diesel lasting very long attempting to do the same job, can you?

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
native pepper
Posts: 1357
Joined: Mon Feb 23, 2015 8:21 am
Location: Tasmania
Has thanked: 5 times
Been thanked: 4 times

Re: Is a diesel engine really the best option?

Post by native pepper »

I'm not going to argue with you Terry, the prius taxi I was in, the driver switched between battery and ICE a number of times during the trip and we never stopped. Asked him about it when I saw him switching something and the battery indicator lit up, that's when he explained how it worked and why they bought it, because they could run round town and just switched to ICE to recharge the battery, said it saved them lot in fuel costs. He also said they dispatched the prius to take me home because it was a hybrid and they could charge the RACT much less for the trip because of the ability to use the battery to reduce costs. Otherwise the trip would have cost the RACT many hundreds of dollars. I know nothing about them other than that experience and don't really care.
bobk
Posts: 158
Joined: Mon Apr 29, 2013 8:22 pm
Location: Adelaide, Highway One, Bolivar

Re: Is a diesel engine really the best option?

Post by bobk »

Going back a pace......Terry I may have not been clear in my initial post. I have friends who have Colorado and Ranger vehicles with turbos who also tow vans, although slightly smaller than our van which is 18'6. Discussion with these people has convinced be that one of those or similar would be a better option. Not considering a 5.7 litre diesel, just a turbocharged 3.0 litre or similar. Regarding kilometer usage, towing would of course be a fraction of the overall distance. On our current trip, I believe we are averaging around 19 to 21 litres per hundred while towing, and 11 to 13 when not, but these figures need to be properly calculated. Yes, I think for our situation, diesel would be better. Additionally, the Commodore is very close to the weight limits where the diesel vehicles I believe are generally above 2.5 tonne capacity, so other conditions must be considered in the engine choice. bk
Bob and Lyn aka Mr & Mrs K.
User avatar
T1 Terry
Posts: 15962
Joined: Fri Nov 23, 2012 3:44 pm
Location: Mannum South Australia by the beautiful Murray River
Has thanked: 50 times
Been thanked: 30 times

Re: Is a diesel engine really the best option?

Post by T1 Terry »

bobk wrote: Tue Apr 13, 2021 8:54 pm Going back a pace......Terry I may have not been clear in my initial post. I have friends who have Colorado and Ranger vehicles with turbos who also tow vans, although slightly smaller than our van which is 18'6. Discussion with these people has convinced be that one of those or similar would be a better option. Not considering a 5.7 litre diesel, just a turbocharged 3.0 litre or similar. Regarding kilometer usage, towing would of course be a fraction of the overall distance. On our current trip, I believe we are averaging around 19 to 21 litres per hundred while towing, and 11 to 13 when not, but these figures need to be properly calculated. Yes, I think for our situation, diesel would be better. Additionally, the Commodore is very close to the weight limits where the diesel vehicles I believe are generally above 2.5 tonne capacity, so other conditions must be considered in the engine choice. bk
In the weight balance line of thinking, I fully agree and the Silverardo or Ram would be the vehicle to go for to achieve that improved weight balance and an improved fuel economy. Tom and Carmel made the switch from a Landcruiser to a Silverardo to improve the weight balance and discovered the bonus of greatly improved fuel economy and a much more relaxed trip ...... well for Carmel anyway, she is the driver, Tom just does the white knuckled navigator part and tells her to slow down a bit ever so often :lol:

As far as fuel economy, a smaller capacity engine can only make the power you need by forced air charging, a turbo or super charger, so more fuel can be added to burn with the increased oxygen in the pressurised cyl charging. This negates any fuel saving and increases the servicing costs because an undersized engine is being force fed to produce torque the basic block was never designed to withstand. The diesel injection must be within very close tolerances or bore washing occurs destroying the over worked engine ....
If you are going to change to another vehicle, make sure you aren't mislead by the little diesel doing just what the big diesel can do fallacy, you might get the performance for a shortened engine life, but it won't be cheaper to run in both fuel economy and servicing costs.

T1 Terry

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
User avatar
T1 Terry
Posts: 15962
Joined: Fri Nov 23, 2012 3:44 pm
Location: Mannum South Australia by the beautiful Murray River
Has thanked: 50 times
Been thanked: 30 times

Re: Is a diesel engine really the best option?

Post by T1 Terry »

native pepper wrote: Tue Apr 13, 2021 2:20 pm I'm not going to argue with you Terry, the prius taxi I was in, the driver switched between battery and ICE a number of times during the trip and we never stopped. Asked him about it when I saw him switching something and the battery indicator lit up, that's when he explained how it worked and why they bought it, because they could run round town and just switched to ICE to recharge the battery, said it saved them lot in fuel costs. He also said they dispatched the prius to take me home because it was a hybrid and they could charge the RACT much less for the trip because of the ability to use the battery to reduce costs. Otherwise the trip would have cost the RACT many hundreds of dollars. I know nothing about them other than that experience and don't really care.
There is an EV button that can be pressed that will drive the vehicle at low speeds and light throttle application .... until the traction battery is drained, then the ICE starts up with no option or input on the drivers part. The later model Prius Prime does have a bigger battery to allow more EV only driving, but it also has a 2.5ltr engine that runs extremely high thermal management window by running within a very narrow band of operation and can achieve up to 39.8%, if anyone is interested in how all that is achieved, there is a very good You Tube video https://priuschat.com/threads/rav-4-hyb ... oo.222842/ that helps explain how it all works .... or has your eyes rolling back in your head real quick :lol:

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
User avatar
T1 Terry
Posts: 15962
Joined: Fri Nov 23, 2012 3:44 pm
Location: Mannum South Australia by the beautiful Murray River
Has thanked: 50 times
Been thanked: 30 times

Re: Is a diesel engine really the best option?

Post by T1 Terry »

Seems the switch to EV is gaining traction in the US to some degree
https://www.bloomberg.com/news/articles ... d-pony-car

Sales are still poor in the US itself, most seem to go into the export market, but with the last syber attack on the petrol pipeline causing dramas, the switch might pick up momentum ....

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves

Return to “Mechanical ... Nuts & Bolts”